For Test 4

Epidemiology of Poliomyelitis

- Almost eradicated, 33 cases in 2018 - Only exists endemically in Pakistan and Afghanistan

Stem Cells

- generative cells capable of dividing to form daughter cells of various types

Turbidimetric and Nephelometric Tests - immune testing (3)

- automated methods that measure the cloudiness of a solution, as occurs when antibodies and antigens are mixed together - when the concentrations of antibodies and antigens are optimal, the initial cloudiness is followed by precipitation - used to to quantify the amounts of proteins, such as antibodies and complement, in serum

Aspirin and ibuprofen are antiprostaglandins. How do they work? (2)

- preventing synthesis of prostaglandins, which drive fever and pain

Vectors of Spotted Fever Rickettsiosis (5)

- requires vectors for host-host transmission - hard tick of the genus Dermacentor - male ticks infect female ticks - female ticks transmit bacteria to eggs (transovarian transmission) - Dermacentor can survive without feeding for 4+ years

Mushroom Grower's Lung - type of Hypersensitivity Pneumonitis

- response to the soil or fungal spores encountered in the growing of mushrooms

Clonal Deletion of B Cells (2)

- self-reactive B cells may become inactive or change their BCR rather than undergo apoptosis - removed from the active B cell repertoire

Transmission of HIV (5)

- transmitted primarily via sexual contact and intravenous drug abuse - Blood transfusions, organ transplants, tattooing, and accidental medical needlesticks also transmit HIV, though rarely --> risk of infection from a needlestick injury involving an HIV-infected patient is less than 1% - Mothers also transmit HIV to their babies across the placenta and in breast milk --> HIV infects approximately one-third of babies born to HIV-positive women

Which cells directly attack abnormal cells in the body? - B cells - Helper T cells - Cytotoxic T cells - Phagocytes

Cytotoxic T cells

How do you check the effectiveness of a vaccine?

Measure the blood antibody level using a Titer

Which organelle is responsible for the degradation of exogenous antigen within an antigen-presenting cell? - Ribosome - Nucleus - Endoplasmic reticulum - Phagolysosome

The phagolysosome is the site of exogenous antigen degradation within an antigen-presenting cell.

Immune privilege

able to tolerate antigens and not mount an immune response (inflammation) - eyes - testicles - placenta and fetus - small extent, brain

Lower respiratory organs are usually axenic. T/F

true

Acid-Fast Bacilli (AFB)

- AKA "acid-fast rods (AFRs)" - bacilli that retain stain during decolorization by acid-alcohol, particularly species of Mycobacterium

Precipitates

- AKA "immune complexes" - large, insoluble, lattice-like complexes - formed when antigens and antibody are mixed in proper proportions

Antitoxins (2)

- Antibodies directed against toxins - Ex. Antivenom is used to treat venomous bites or stings

Pseudomonas Infection

- Blood infection causes fever, chills, and shock

Superficial and cutaneous mycoses of the hair, nails, and skin are generally not life threatening. T/F

true

Pathogen and Virulence Factors of Brucellosis

- Brucllea melitensis is a genus of nonmotile, aerobic, Gram-negative coccobacilli that lack capsules - B. melitensis infects goats and sheep - B. abortus infects cattle - B. suis infects swine - B. canis infects dogs, foxes, and coyotes - IN ANIMALS, lives as an intracellular parasite in organs such as the uterus and placenta (these organs are not infected in humans) - has endotoxin that causes some of the signs/symptoms - bacterium has the ability to grow and multiply inside phagocytic cells, evading antibodies and some antibacterial drugs

Viral Hepatitis Pathogen and Pathogenesis; Part 1

- Hepatovirus Hepatitis A virus (HAV, +ssRNA) - Orthohepadnavirus Hepatitis B virus (HBV, dsDNA) - Hepacivirus Hepatitis C virus (HCV, +ssRNA) - Deltavirus Hepatitis delta virus (HDV, -ssRNA) - Hepevirus Hepatitis E virus (HEV, +ssRNA) Transmission - HAV/HEV: fecal/oral transmission - HBV/HCV/HEV: needles/sex

Pathogen of Chickenpox and Shingles (2)

- Human alphaherpesvirus 3 (dsDNA) causes both diseases - Historically known as Varicella-zoster virus (VZV)

Killed vaccines stimulate an antibody immune response. Why? (2)

- all types of killed vaccines are recognized by the immune system as exogenous antigens - humoral immunity targets exogenous antigens (cell-m targets endogenous)

Class II MHC Protein

- found ONLY on antigen-presenting cells (APCs) in addition to MHC I - found on B lymphocytes, macrophages, dendritic cells - nonspecific; can bind thousands of different epitiopes (unlike enzymes)

Secondary Lymphoid Organs

- lymph nodes - spleen - tonsils - mucosa-associated lymphatic tissue (MALT)

Erythrocytes (2)

- most numerous of the formed elements - Carry oxygen and carbon dioxide in the blood

Immunofiltration assays (2)

- rapid modification of ELISA test using membrane filters rather than plates - Because of the large surface area of a membrane filter, reactions proceed faster, and assay times are significantly shorter than a traditional ELISA.

Primary Lymphoid Organs (2)

- red bone marrow - thymus

What is the end of each arm called? (3)

- variable region - the ends of BCRs on any one B cell differ from the ends of any other B cell's BCRs --> the AA sequence varies among B cells

The events in salmonellosis.

1. salmonella attaches to epithelial cells lining the small intestine 2. salmonella triggers endocytosis 3. salmonella multiplies within food vesicle 4. Salmonella kills host cell, inducing fever, cramps, and diarrhea 5. Bacteremia: Salmonella Typhi and Paratyphi move into bloodstream and can become systemic (Typhoid Fever)

The cytoplasmic membrane of a professional APC has about ___ MHC II molecules

100,000

Autoantigens (2)

- AKA "self-antigens" - components of normal body cells derived from normal cellular processes

Cholera

- Caused by Vibrio cholerae --> G- vibrio - Cholera toxin gene is encoded by bacteriophage --> Toxin triggers secretion of electrolytes by intestinal cells. Water follows electrolytes via osmosis - Pandemics have occurred throughout history - Severe fluid and electrolyte loss due to massive diarrhea --> Dehydration, acidosis, shock, coma, death

Pathogen and pathogenesis of Variant Creutzfeldt-Jakob Disease (vCJD)

- Caused by abnormal protein, prion PrP - Prions may remain dormant for many years - Accumulation of prion PrPleads to neuron death

Botulism

- Caused by intoxication from botulinum toxin of Clostridium botulinum - botulism toxin is one of the more powerful natural poisons --> adversely affects synapses of the peripheral nervous system - 3 forms (foodborne, infant, wound) - rare

Diagnosis, treatment, and prevention of Toxoplasmosis

- Diagnosed mainly by detecting organisms in tissues - Treatment needed only in AIDS patients, pregnant women, and newborns - Prevention is difficult because T. gondii has numerous hosts

Streptococcus pyogenes of Eryispelas (PROF NOTES) (5)

- G+ coccus, arranged in chains - Pyrogenic toxin: superantigen and causes red rash --> Superantigens nonspecifically activate THcells - M protein: inhibit C3b - Capsule, adhesion factors, exoenzymes

Epidemiology of of Eryispelas (2)

- Transmitted by person-to-person contact or via fomites - Mostly occurs in children and the elderly

Plasma Cells (4)

- actively fight exogenous antigens - secrete antibodies - don't display BCRs - have extensive rough endoplasmic reticulum and many Golgi bodies involved in the synthesis, packaging, and secreting of the immunoglobulins

Specificity (2)

- adaptive immune response acts against only one particular antigen - innate gives general responses to PAMPs

Chemokines (2)

- an immune system cytokine that signals leukocytes to rush to the site of inflammation or infection and activate other leukocytes - released by leukocytes already at the site of infection

Sebum (2)

- an oily lipid secreted by oil (sebaceous) glands in the dermis - chemicals in sweat and sebum are antimicrobial, preventing the growth of many microorganisms

Pathogenesis of Cellulitis

- bacteria occasionally colonize the skin and then invade through scratches, abrasions, cold sores, or other wounds where the skin's integrity is compromised - Children are often infected just below the nose, where frequent wiping away of mucus abrades the skin - Cellulitis in adults usually occurs in the legs.

psittacosis

- caused by Chlamydophila psittaci - a disease of birds that can be transmitted to humans, in whom it typically causes flulike symptoms, though in some patients severe pneumonia occurs - Doxycyclin

Staphylococcal Scalded Skin Syndrome (4)

- cells of the outer epidermis separate from one another and from the underlying tissue - caused by exfoliative toxin of Staphylococcus aureus which epidermis peels off - reddening and wrinkling of the skin that typically begins near the mouth, spreads over the entire body, and is followed by large blisters that contain clear fluid lacking bacteria or white blood cells --> Within two days, the affected outer epidermis peels off in sheets, as though the flesh had been dipped into boiling water

Susceptibility of Chickenpox and Shingles (2)

- chickenpox is highly contagious to those who are not immunized or have not had it before - persons how have had chickenpox previously are generally immune

inhalational anthrax

- common cold or flu-like symptoms --> sore throat, mild fever, myalgia (muscle aches), mild cough, and malaise - After several days, the symptoms progress to include more severe coughing, nausea, vomiting, fainting, confusion, lethargy, shock, and death

Types of Antigens (3)

- exogenous - endogenous - autoantigens

Farmer's Lung - type of Hypersensitivity Pneumonitis

- farmers chronically exposed to spores from moldy hay

Eosinophils (2)

- function primarily to destroy parasitic worms - eosinophilia (accumulation of eosinophils in the blood)

lymphadenopathy

- irritation of the lymphatic system in which lymph nodes become enlarged and tender

Are all viruses cytopathic?

- no, not all viruses kill their host cell

Cortex of Lymph Node (3)

- outer portion - consists of a tough capsule surrounding primary follicles --> B cell CLONES replicate here

Spleen (8)

- secondary lymph organ - similar in structure and function to lymph nodes - have a tough outer capsule like the nodes - filters BLOOD, not lymph - removes bacteria, viruses, toxins, and other foreign matter - cleanses the blood of old and damaged blood cells - stores blood platelets - stores blood components, such as iron

Helper T Cells

- secrete cytokines to activate other cells of the immune system

How does the "chill" associated with fever come about? (2)

- skin BVs constrict as the fever progresses which undoes the vasodilation of inflammation - constricted skin vessels carry less blood making the skin feel cold

Mast Cells

- specialized cells located in connective tissue that release Histamine when they are exposed to Complement

How is the epidermis replaced? (4)

- the deepest cells continually divide, pushing their daughter cells toward the surface - the rising daughter cells flatten and die - they are eventually shed as flakes - Microorganisms that attach to the skin's surface are sloughed off with the flakes of dead cells

2 Significant Examples of Type II Hypersensitivity

- the destruction of donor red blood cells following an incompatible blood transfusion (transfusion reaction) - destruction of fetal red blood cells in hemolytic disease of the newborn

The "crisis" of a fever

- the infection comes under control, fewer active phagocytes means less pyrogens - thermostat is reset to 37 C - sweating - metabolic rate lowers - skin BVs dilate **These are signs that the infection has been overcome and body temp is returning to normal.

What three genera of ascomycetes cause most dermatophytoses?​ (pathogens of dematophytoses)

1. Trichophyton 2. Microsporum 3. Epidermophyton are the more common causes of ringworms. **All three genera cause skin and nail infections, and Trichophyton species also infect hair.

Review - Which is the most common cause of viral gastroenteritis? A. Norovirus. B. Astrovirus. C. Rotavirus. D. Calicivirus.

A - Norovirus is responsible for 90% of viral gastroenteritis cases.

Eflornithine is very effective against which disease? A. Primary amebic meningoencephalopathy. B. Cryptococcal meningitis. C. African sleeping sickness. D. Variant Creutzfeldt-Jakob disease (vCJD)

C

Review - A pseudomembrane in the back of the throat is a sign of which disease? A. Common cold. B. Strep throat. C. Diphtheria. D. Rhinosinusitis.

C

Review - Which of these protozoa uses pseudopods for motility? A. Giardia intestinalis. B. Cryptosporidium parvum. C. Entamoeba histolytica. D. Taenia saginata.

C - Entamoeba histolytica is an amoeba and moves with pseudopods

Review - Why is Leptospira interrogans highly motile? A. It has a tuft of flagella. B. It has cilia. C. It has two axial filaments. D. It has peritrichous flagella.

C - The spirochete L. interrogans is highly motile because of its two axial filaments, one at each end.

What is the most common sexually transmitted bacterium?

Chlamydia trachomatis

Food Allergens - LOCAL

May cause diarrhea and other gastrointestinal signs and symptoms

Review - Which is longer lasting and creates memory B cells, active immunization or passive immunotherapy?

active immunization

What is the most common bacterial infection of the nervous system?

bacterial meningitis

chemotactic factors

chemicals that recruit leukocytes to a site

C3am C4a, C5a

each inflammatory agents that cause localized vascular dilation, leading to inflammation

How are vaccine types named?

named for the type of antigen used in the inoculum

Review - Why are special stains or phase contrast microscopy necessary to observe Treponema pallidum? A. T. pallidum does not take up crystal violet or safranin. B. T. pallidum is a mycoplasma and thus too small to be seen with a regular light microscope. C. T. pallidum is too thin to be visible with regular light microscopy. D. T. pallidum is an acid-fast staining bacterium.

C - At 0.1 μm in diameter, T. pallidum is too thin to be viewed with a regular light microscope

Conjunctivitis

Inflammation of the conjunctiva (lining of an eyelid) - AKA "pinkeye" - Haemophilus influenzae is the most common bacterial cause - Acanthamoeba, a protozoan, can cause both conjunctivitis and keratitis - treat with topical antimicrobial drugs - no antiviral drug available

An antigen that is potent enough to activate a B cell on its own is known as: - BCR. - T-independent antigens. - T-dependent antigens. - antibodies.

T-independent antigens.

axonal transport

The transportation of materials from the neuronal cell body to distant regions in the dendrites and axons, and from the axon terminals back to the cell body.

3 layers of the heart

an outer fibrous pericardium, a muscular myocardium, and a thin inner endocardium - endocardium lines the atria and ventricles, extends to cover the valves, and is continuous with the linings of the blood vessels

Asymptomatic infections - polio conditions

account for about 90% of all cases.

Which of the following are phagocytic cells descended from monocytes? - alveolar macrophages - dendritic cells - microglial cells - alveolar macrophages and dendritic cells - alveolar macrophages and microglial cells

alveolar macrophages and microglial cells

autoimmunity

an immune system does occasionally produce antibodies and cytotoxic T cells that target normal body cells

Autoantibodies to red blood cells

cause hemolytic anemia

What is urticaria? - purpura - anaphylaxis - hives - hemolysis

hives - The common name for urticaria is hives--red, itchy patches of skin.

mycophenolate mofetil - cytotoxic drug

inhibits purine synthesis

Variolation

inoculation of smallpox into the skin - Chinese officials therefore adopted a policy of deliberately infecting young children with particles of ground smallpox scabs from other children who had survived mild cases. By doing so, they succeeded in significantly reducing the population's overall morbidity and mortality from the disease.

What antibacterial chemical is present in tear fluid? - defensins - antibodies - lysozyme - complement - interferon

lysozyme

Is every molecule an effective antigen?

no - different properties make certain molecules more effective at provoking adaptive immunity --> shape, size, complexity

Both pathways converge on C3 (3)

cleaves into C3a and C3b - C3a: inflammation - C3b: opsonizationand membrane attack complex

Are there openings that allow microbial colonization of the central nervous system?

no! - the CNS is axenic --> it has NO NORMAL MICROBITOTA

What can happen with whole agent vaccines?

nonantigenic portions of the microbe occasionally stimulate a painful inflammatory response in some individuals

Do vaccines prevent disease OR infection?

disease! they are meant to infect

Virulence Factors of Staphylococci - Folliculitis

enzymes, structures that enable them to evade phagocytosis, and toxins

Which of the following leukocytes is primarily responsible for an immune response against helminths? - basophils - natural killer cells - neutrophils - eosinophils

eosinophils

What is commonly used to kill microbes for use in vaccines?

formaldehyde denatures proteins and nucleic acids.

autoantibodies to platelets

give rise to bleeding disorders

Most often, antigens are composed of __________. - nucleic acids - lipids - glycoproteins - polysaccharides

glycoproteins

Which structure do antigen presenting cells utilize to directly help them present bacterial antigens? - Golgi apparatus - Mitochondria - Phagolysosome - Nucleus

phagolysosome

tuberculin

protein solution obtained from Mycobacterium tuberculosis

Virulence factors of Toxoplasma gondii

the ability of oocysts and of pseudocysts to parasitize a wide variety of hosts, the ability of Toxoplasma to infect many different cells within a host, and the ability of the parasite to survive intracellularly

What is the first step of a cell-mediated immunity response?

the activation of a specific clone of cytotoxic T cells

Cell-mediated adaptive immune responses involve:

the activity of cytotoxic T lymphocytes in killing cells infected with intracellular bacteria and viruses

Serum

the liquid remaining when formed elements and clotting proteins are removed from blood

passive immunotherapy

the technique of transferring protective antibodies to susceptible individuals

Where is the antigen-binding site on BCRs?

the variable region at the end of the arms! - they are complementary in shape to the 3D shape of an epitope - exact binding accounts for the specificity of an antibody immune response

Clonal deletion occurs in the __________. bone marrow blood thymus thyroid

thymus - thymus is where the T cells migrate to mature and also where they may undergo clonal deletion.

BCRs of one cell differ from the BCRs of all other B cells. T/F

true

How are passive immune responses advantageous? (2)

- fast - but do not confer immunological memory because B and T lymphocytes are not activated

How to Slow AIDS Epidemic

--- Abstinence and mutually faithful monogamy between uninfected individuals are the only truly safe sexual behaviors. Studies have shown that whereas condoms reduce a heterosexual individual's risk of acquiring HIV by about 69%, the benefit of condom usage to a population can be undone by an overall increase in sexual activity that may result from a false sense of security that condoms provide safe sex. --- Use of new, clean needles and syringes for all injections, as well as caution in dealing with sharp, potentially contaminated objects, can reduce HIV infection rates. If clean supplies are not available, 10% household bleach deactivates HIV on surfaces uncontaminated by a large amount of organic material (blood, mucus). --- Antiviral drugs given to pregnant women have reduced transfer of HIV across the placenta and in breast milk. Generally, HIV-infected mothers should not breast-feed their infants, though feeding with formula made with contaminated water is often more dangerous, triggering life-threatening diarrhea. WHO recommends formula only when it is "acceptable, feasible, affordable, sustainable, and safe." --- Screening blood, blood products, and organ transplants for HIV and anti-HIV antibodies has virtually eliminated the risk of HIV infection from these sources. --- Proper use of gloves, protective eyewear, and masks can prevent contact with infected blood. --- Researchers have determined that men who are circumcised reduce their risk of infection with HIV through sexual activity by at least 60%. Circumcision lowers their partner's risk by 30%. --- For many individuals, pre-exposure prophylaxis (PrEP), which involves taking a daily oral dose of tenofovir (an antiviral nucleoside analog), prevents sexual acquisition of HIV. --- Women who apply 1% tenofovir gel vaginally before and after sex significantly reduce the chance of infection from HIV-positive men, particularly women whose vaginas are colonized with Lacotbacillus spp. rather than with Gardnerella vaginalis ; the latter bacterium destroys tenofovir

Type A Blood

A-Antigens Anti-B antibodies Donates to A or AB Receives from A or O

Review - What is the common name of tinea pedis?

athlete's foot

Helper T lymphocyte, TH(CD4 cell) (7)

- CD4 glycoproteins in the cells' cytoplasmic membranes --> CD4 positive (CD4+) cells - help regulate the activity of B cells and cytotoxic T cells during immune responses by providing necessary signals and growth factors - Activate B cells, cytotoxic T cells, macrophages, and dendritic cells - CD4 only binds to MHC II - secrete cytokines - 2 types - distinguished by secretions and cell-surface proteins

Type II Hypersensitivity (3)

- CYTOTOXIC hypersensitivity - results when cells are destroyed by an immune response—typically by the combined activities of complement and antibodies - component of many immune diseases

Lymphatic System

- Composed of lymphatic vessels and lymphatic cells, tissues, and organs - Screen the tissues of the body for foreign antigens by providing a surveillance point - B and T cells are typically found in the lymphatic system

immunodeficiency diseases (2)

- Conditions resulting from defective immune mechanisms - 2 general types (primary and acquired)

Diagnosis, treatment, and prevention of African Sleeping Sickness

- Diagnosed by microscopic observation of trypanosomes in blood, lymph, spinal fluid, or tissue biopsy --> In mammals, the protozoa are long and thin, with a single long flagellum running along the cell and extending past the posterior end - Prevented by avoiding Tsetse fly - Treatment based on disease stage with specific antimicrobials --> Must be done soon after infection to be successful - Insecticide application can help reduce occurrence - NO VACCINE

Pathogenesis for Rocky Mountain Spotted Fever (2)

- Disease occurs from damage to blood vessels - May lead to death if not treated within first 5 days

Protozoan Diseases of the Nervous System

- Protozoan infections of the nervous system are rare - 2 diseases --> African sleeping sickness & Meningoencephalitis

Common Skin Infecting Bacteria (6)

- Staphylococcus - Streptococcus - Cutibacterium - Bartonella - Pseudomonas - Rickettsia

molecular mimicry (3)

- occurs when an infectious agent has an epitope that is very similar or identical to a self-antigen - In responding to the invader, the body produces antibodies that are autoantibodies (antibodies against self-antigens), which damage body tissues - some virally triggered autoimmune diseases also result from molecular mimicry

Diagnosis, Treatment, and Prevention of Zika Virus

- real-time PCR to detect Zika RNA in patients, or they can detect anti-Zika antibodies in the serum of patients by using an enzyme-linked immunosorbent assay (ELISA) - no standard treatment; fluid, rest, acetaminophen - vaccine being developed

Primary Response (4)

- small amounts of antibodies are produced - may take days before sufficient antibodies are made to completely eliminate the toxoid from the body - basically ends when the plasma cells die - memory B and T cells created

Epidemiology of Respiratory syncytial virus (RSV) infection

- spreads easily during close contact with infected persons - Spread via respiratory droplets is less frequent - Immunocompromised older patients and babies, especially those who are premature, are immune impaired, are exposed to tobacco smoke, attend day care, or have older school-aged siblings, are most at risk - prevalent in the US; 98% of children in day care centers are infected by age 3

disseminated intravascular coagulation (DIC) - Potential effects of endotoxin

- the formation of blood clots within blood vessels throughout the body - triggered by Lipid A

Epidemiology of Staphylococcus epidermidis for Folliculitis (4)

- thrives on almost every square millimeter of human skin; normal microbiota of the skin - lacks the virulence factors of S. aureus, and seldom causes disease - can be an opportunistic pathogen in immunocompromised patients --> or when introduced into the body via intravenous catheters or on prosthetic devices such as artificial heart valves

Labeled Immunoassays - immune testing (4)

- use antibody molecules that are linked to some molecular "label" that enables them to be detected easily --> Labels: radioactive chemicals, fluorescent dyes, and enzymes - Automated machines can detect and quantify labels - Labeled immunoassays using radioactive or fluorescent labels can be used to detect either antigens or antibodies

Antibodies Function in Several Ways

1. Activation of complement and inflammation 2. Neutralization 3. Opsonization 4. Agglutination 5. Antibody-dependent cell-mediated cytotoxicity (ADCC)

The action of cholera toxin in intestinal epithelial cells.

1. Cholera toxin binds to membrane of epithelial cells 2. Portion of toxin (part of A) enters cell 3. A1 activates adenylate cyclase (AC) 4. Cyclic AMP (cAMP) is synthesized 5. Cyclic AMP stimulates cell to secrete Cl-, Na+, and other electrolytes 6. Water follows electrolytes to lumen

4 Steps of Fever

1. Phagocytes release Pyrogens 2. causing Hypothalamus to release prostaglandin which resets the hypothalamic thermostat 3. Nerve impulses cause shivering, higher metabolic rate, inhibition of sweating, vasoconstriction 4. These processes increase body temp to the point set by the hypothalamic thermostat

eosinophilia (6)

1. begins with mast cell degranulation 2. degranulation releases peptides that stimulate the release of eosinophils from the bone marrow 3. Once in the blood, eosinophils are attracted to the site of mast cell degranulation, where they themselves degranulate 4. Eosinophil granules produce large amounts of leukotrienes --> increase movement of white blood cells from blood vessels and stimulate smooth muscle contraction --> thereby contributing greatly to the severity of a hypersensitivity response

What is the function of iron-binding proteins? How is it relative to defense?

1. transporting and storing iron 2. they sequester iron so it's unavailable to invading microorganisms

Correctly order the steps involved cellular immunity: 1) The Tc recognizes the infected host cell 2) The Tc interacts with epitope presented by MHC-I on the dendritic cell 3) The Tc secretes perforin and granzyme, causing apoptosis 4) The helper T cell activates the Tc cell

2, 4, 1, 3 2) The Tc interacts with epitope presented by MHC-I on the dendritic cell 4) The helper T cell activates the Tc cell 1) The Tc recognizes the infected host cell 3) The Tc secretes perforin and granzyme, causing apoptosis

Review - Which gonorrhea patients most often lack obvious symptoms? A. Women. B. Immunocompromised people. C. Men. D. The elderly.

A - Among women who are infected, 50-80% lack signs or symptoms of gonorrhea.

Positive ELISA

A positive reaction in a well, indicated by the development of color, can occur only if the labeled anti-antibody has bound to antibodies attached to the antigen of interest. The intensity of the color, which can be estimated visually or measured accurately using a spectrophotometer, is proportional to the amount of antibody present in the serum.

Which two groups of humans are at greatest risk from toxoplasmosis?

AIDS patients and first-trimester fetuses are at greatest risk from toxoplasmosis.

Review - What provides significant nonspecific defense against pathogens? (3)

COMBO OF: - barrier function of epidermis - continual replacement of epidermis - phagocytic dendritic cells

Rubella - compared to Measles

Causative Agent: Togaviridae: Rubivirus Primary Patients: Child, fetus Complications: Birth defects Skin Rash: Mild Koplik's Spots: Absent

Which molecule triggers apoptosis? - IL-2 - Granzyme - Perforin - Gamma-interferon - MHC

Granzyme

Details of Release, Assembly, and Maturation of HIV

HIV actively participates in its release from the cell. A viral protein selects a lipid raft—a region of regularly packed lipids—in the cytoplasmic membrane as the point of exit. As the virus blebs from the cell, components of the raft become the envelope of the virion. Once the virus is outside the cell, capsomeres organize to form an immature capsid, and viral protease cleaves a polypeptide within the capsid to release functional proteins. The proteins cause the virus to mature and become infective. Protease inhibitors—drugs that interfere with the function of protease—have become a standard therapeutic agent in the treatment of HIV infection and have significantly lengthened the life expectancy of patients.

Entry of HIV

HIV triggers the cell to endocytize the virus; that is, the cell's cytoplasmic membrane forms a pocket and folds in to surround the virus, forming a vesicle holding the virus.

Review - Which chemical released during type I hypersensitivity responses causes contractions of smooth muscle, such as in the bronchi? A. Histamine B. Antibodies C. Proteases D. Prostaglandins

Histamine stimulates contractions in the smooth muscles of the bronchi

Which of the following cytokines promotes the development of a cell-mediated immune response? - IL-4 (interleukin-4) - tumor necrosis factor (TNF) - IL-12 - chemokines - alpha interferon

IL-12

Which of the following immunoglobulins is produced by plasma cells in response to an allergen? - IgM - IgA - IgE - IgG - IgD

IgE

Which patients are most susceptible to exfoliative strains of S. aureus?

Infants, the elderly, and immunosuppressed patients are most susceptible to SSSS.

Review - Is it possible to have an allergic reaction to pollen upon the first exposure? Why or why not? A. No, multiple exposures are necessary before an allergic reaction is possible. B. No, antibodies must be formed during the first exposure. C. Yes, the first exposure can be severe enough to generate an allergic response. D. Yes, it is possible to be genetically predisposed to be allergic to pollen.

No, antibodies must be formed during the first exposure. - Upon exposure to the pollen antigen, antibodies are formed that are responsible for the allergic response after subsequent exposure

What is produced by the process of clonal expansion? - Plasma cells and memory B cells - Memory B cells - Plasma cells - Plasma cells, T cells, and memory B cell

Plasma cells and memory B cells

Opportunistic infections typical of AIDS but rare otherwise include - tuberculosis and shingles. - tuberculosis. - Pneumocystis pneumonia and Kaposi's sarcoma. - Pneumocystis pneumonia. Kaposi's sarcoma.

Pneumocystis pneumonia and Kaposi's sarcoma

What factors may trigger the reactivation of latent herpesviruses and the recurrence of symptoms?

Stress, trauma, sunlight, menstruation, or diseases such as AIDS may cause recurrent symptoms as a result of immune suppression.

Integration of HIV

The dsDNA made by reverse transcriptase enters the nucleus and becomes part of a human DNA molecule. There it remains as a part of the cell for life—a condition known as ​latency​.

Booster Immunization

When a titer is low, antibody production can be bolstered by administration of more antigen

Viremia

When viruses infect the blood --> yellow fever, mononucleosis, cytomegalovirus disease, and hemorrhagic fevers

Epidemiology of Rabies

Zoonotic disease, typically bats in USA. (a disease spread from animal reservoirs to humans) - Bats are the source of most cases of rabies in humans, causing about 75% of cases

Zoonosis

a disease of animals transmitted to humans

type 1 helper T cells (Th1 cells)

assist cytotoxic T cells and stimulate and regulate innate immunity

3 Types of T Cells

based on surface glycoproteins and characteristic functions - Cytotoxic T lymphocyte, TC(CD8 cell) - Helper T lymphocyte, TH(CD4 cell) - Regulatory T lymphocyte, TReg

Which of the following is a type of blood cell that undergoes degranulation in type I hypersensitivity reactions? - B cell - T cell - macrophage - plasma cell - basophil

basophil

Probiotics (2)

live microorganisms administered to improve health and prevent disease - may be needed in the future with the heavy use of antimicrobial agents in soaps

What happens if TLRs fail?

much of an immune response collapses, leaving the body open to attack by myriad pathogens

Incubation Period of Chickenpox and Shingles

two to three weeks

Antigen-antibody complexes trapped in tissues and triggering complement activation or mast cell degranulation are characteristic of: - autoimmunity. - type II hypersensitivity. - type I hypersensitivity. - graft rejection. - type III hypersensitivity.

type III hypersensitivity

Would a third exposure be even more powerful than the second?

yes

What is the most efficient and cost-effective way to control infectious diseases? - active immunization by vaccination - variolation - autoimmunization - immune testing - passive immunotherapy using immunoglobulins

active immunization by vaccination

The leukocytes called natural killer lymphocytes: - are nonspecific leukocytes that secrete toxins onto the surface of virus-infected cells. - are specialists in killing bacteria. - release prostaglandins and leukotrienes in response to microbes. - increase in allergies and helminth infection. - respond to the coating of a pathogen by complement.

are nonspecific leukocytes that secrete toxins onto the surface of virus-infected cells

Human diseases caused by poxviruses (Genus Orthopoxvirus)

**THEY ARE DNA VIRUSES - smallpox (Variola virus) 3 diseases of animals which rarely affect humans - orf (sheep and goat pox) - cowpox - monkeypox

Spotted Fever Rickettsiosis (5)

- Arthropod-borne rickettsias, Rocky Mountain spotted fever is most severe - One week post-infection: fever, headache, abdominal pain, vomiting, and muscle pain. Organ failure in severe cases. - In 90% of cases, non-itchy spotted rash on trunk and appendages (these sites aren't involved in chickenpox or measles) - In 50% of cases, the rash develops into subcutaneous hemorrhages called petechiae - in severe cases, the respiratory, central nervous, gastrointestinal, and renal systems fail - with treatment, only 0.5% of patients die

Epidemiology of Giardiasis

- Infection results from ingesting cysts in contaminated water - Hikers and campers are at particular risk - Diagnosed by microscopic observation of Giardia in stool - Treat with metronidazole or tinidazole - Oral rehydration therapy may be needed - Prevention relies on using good hygiene and filtering water in endemic areas

Roseola (5)

- herpesvirus in the genus Roseolovirus, known simply as human herpesvirus 6 (HHV-6) - an endemic illness of children characterized by an abrupt fever, sore throat, enlarged lymph nodes, and a faint pink rash on the face, neck, trunk, and thighs - link HHV-6 with the development of multiple sclerosis in adults --> some evidence that HHV-6 infection makes individuals more susceptible to HIV infection and AIDS - No pharmaceutical treatment exists.

Can SSSS kill?

- if it occurs, is most often due to secondary infections of skinless areas by yeasts such as Candida albicans or bacteria such as Pseudomonas aeruginosa

5 Phagocytes

- neutrophils - eosinophils - dendritic cells (ch. 16) - macrophages - monocytes

human diploid cell vaccine (HDCV)

- prepared from deactivated rabies viruses cultured in human diploid cells - administered intramuscularly on days 0, 3, 7, and 14 after exposure to rabies virus - can also be administered before infection to workers who regularly come into contact with animals - Rabies is one of the few infections that can be treated with active immunization because the progress of viral replication and movement to the brain is slow enough to allow effective immunity to develop before disease develops

Type I (α and β) Interferons (7)

- present early in viral infections --> virally infected monocytes, macrophages, and some lymphocytes secrete small amounts of alpha interferon (IFN-α) --> virally infected fibroblasts secrete small amounts of beta interferon (IFN-β) - act on the cells that secrete them; trigger protection for nearby uninfected cells - bind to IFN receptors on the cyto-membrane --> triggers production of AVPs - IFNs activate NK and other lymphocytes

Naturally Acquired Active Immunity (4)

- resulting from infection - contact with pathogens - body responds to exposure to pathogens and environmental antigens by mounting specific immune responses - body is naturally and actively engaged in its own protection

Chlamydophila pneumoniae

- spread in respiratory droplets, causes pneumonia as well as bronchitis and rhinosinusitis - infections with this bacterium are mild, producing only malaise and a chronic cough, and do not require specific treatment, though azithromycin or doxycycline can be prescribed

Immunotherapy - Prevent Against Type I Hypersensitivity (6)

- the administration of a series of injections of dilute allergen, usually once a week for many months - may change the helper T cell balance from Th2 cells to Th1 cells, reducing the production of antibodies - may stimulate the production of IgG, which binds antigen before the antigen can react with IgE on mast cells and basophils - reduces the severity of allergy symptoms by roughly 50% in about two-thirds of patients with upper respiratory allergies - series of injections must be repeated every two to three years - NOT effective in treating asthma

How do some bacteria like Staphylococcus aureus respond to an iron shortage? (3)

- they secrete their own iron-binding compounds called siderophores - siderophores have a greater affinity for iron than does transferrin or other proteins --> bacteria that produce siderophores can in effect steal iron from the body

Anaplasmosis

- tick-borne disease caused by a rickettsia - Anaplasma phagocytophilium, manifesting with flulike signs and symptoms - formerly called human granulocytic ehricliosis

Dermis (2)

- tough, leathery structure composed of loosely packed cells, connecting protein fibers, small muscles, sweat glands, sebaceous (oil) glands, blood vessels, nerve endings, and hair follicles, which produce hairs that grow up through the dermis and epidermis - provides strength and flexibility and, along with its blood vessels, supports the growth of the overlying epidermis

Pathogenesis of Staphylococcal Scalded Skin Syndrome (SSSS) (3)

- toxemia: blood carries exfoliative toxins from sites of infection throughout the body - body restores the lost epidermis within 7 to 10 days after protective antibodies circulate in the blood --> scarring does not occur because the toxin does not affect the dermis

How is iron transported in humans? Why? (3)

- transferrin, a transport protein, carries iron via plasma to cells - transferrin-iron complexes binding to their receptors triggers the cell to take up Iron via endocytosis - Why is it needed? Iron is relatively insoluble

Pathogenesis and Epidemiology of Pneumocystis pneumonia (PCP)

- transmission most likely occurs through inhalation of droplet nuclei containing the fungus --> P. jirovecii cannot survive on its own in the environment - Once the fungus enters the lungs of an immunocompromised patient, it multiplies rapidly, extensively colonizing the lungs - infection is often asymptomatic in healthy people

Pathogenesis and epidemiology of Necrotizing Fasciitis (4)

- transmitted person-to-person through breaks in skin - has developed following surgery, abortion, and seemingly harmless events such as an insect bite or a needlestick to draw blood - Diabetes, cancer, and chickenpox increase the risk for developing necrotizing fasciitis - Death occurs in ~20% of patients

Arboviruses

- viruses transmitted between hosts by bloodsucking arthropods such as mosquitoes - arthropod-borne viruses - Mosquito-borne arboviruses are responsible for various types of Arboviral encephalitis - These zoonotic diseases typically affect birds, horses, and rodents, and only rarely do they affect humans

Leukocytes (3)

- white blood cells - Involved in defending the body against invaders - Divided into granulocytes and agranulocytes

Tularemia

- zoonosis - Skin lesions and swollen lymph nodes at infection site - Ascending lymphangitis - fever, chills, headache, malaise, fatigue, shortness of breath, joint stiffness, and myalgia - general manifestations may last for months or years

Life cycle of Taenia solium.

1. eggs and egg-filled proglottids are passed into environment in feces 2. Intermediate hosts ingest eggs on contaminated food 3. eggs hatch into larvae that penetrate the intestinal wall and migrate to other tissues 4. larva develops into a cysticercus in muscle 5. human ingests cysticercus in raw or undercooked contaminated meat 6. cysticercus excysts and attaches to mucosa of small intestine as a scolex, which matures 7. adult worm forms new proglottids 1. cycle repeats

Review - What is the role of hemagglutinin in influenza infections? A. Hemagglutinin binds to epithelial cells, triggering endocytosis of the virus. B. Hemagglutinin hydrolyzes mucus in the lungs, allowing influenza virus access to epithelial cells. C. It forms the envelope of influenza virus during viral release. D. It is an RNA polymerase that replicates the influenzavirus genome once a cell is invaded.

A

Comparison of the Polio Vaccines - Sabin Vaccine Attenuated, oral polio vaccine (OPV)

Advantages: Provides lifelong immunity without boosters; triggers secretory antibody response similar to natural infection; easy to administer; results in herd immunity Disadvantages: Less stable than IPV; can mutate to disease-causing form; poses risk of development of polio in immunocompromised contacts of immunized individuals

Epidemiology of Zika Virus

Aedes aegypti are aggressive mosquitoes that seem to prefer human blood, bite during the day, and lay their eggs in old tires, toilet tanks, flower vases, pets' water bowls, and even a small drop of water inside a bottle cap or held by plastic litter

Jock Itch; Tinea cruris

Agents: - T. rubrum; T. mentagrophytes var. interdigitale; E. floccosum Common Signs: - Red, raised lesions on and around the groin and buttocks Source: - Usually spreads from the feet

Athlete's Foot; Tinea Pedis

Agents: - Trichophyton rubrum; T. mentagrophytes var. interdigitale; Epidermophyton floccosum Common Signs: - Red, raised lesions on and around the toes and soles of the feet; webbing between the toes is heavily infected Source: - Human reservoirs in toe webbing; carpeting holding infected skin cells

If a woman receives a kidney from her brother, what type of transplantation has occurred? A. An autograft B. An isograft C. A xenograft D. An allograft

An allograft is a transplantation between genetically distinct members of the same species

Review - What type of ABO blood group antibodies does a person with blood type B typically have?

Anti-A antibodies - A person with blood type B has B antigens on the surface of their red blood cells. If this person has preexisting anti-blood antigen antibodies, they would be anti-A antibodies.

Which cells possess MHC class II proteins? - All white blood cells - Nucleated cells - Antigen-presenting cells - Red blood cells

Antigen-presenting cells ONLY

1. Electrophoresis - First Step of Immunoblot

Antigens in a solution (in this example, HIV proteins) are placed into wells and separated by gel electrophoresis. Each of the proteins in the solution is resolved into a single band, producing invisible protein bands. (In the figure, the artist has colored the invisible bands to show you where they are.)

Which of the following would you likely see on the surface of a human dendritic cell following phagocytosis of a bacterium? - Class II MHC with dendritic cell antigens - Class II MHC with engulfed bacterial antigens - Class I MHC with dendritic cell antigens and - - Class II MHC with engulfed bacteria - Class I MHC with dendritic cell antigens

Class I MHC with dendritic cell antigens and Class II MHC with engulfed bacteria

What would a virally infected skin epithelial cell have on its cell surface? - Class II MHC with liver cell antigens - Class I MHC with skin cell antigens - Class II MHC with viral antigens - Class II MHC with macrophage antigen

Class I MHC with skin cell antigens

Review - Which organism causes the skin to slough off, particularly in the very young and in people with compromised immune systems? A. Staphylococcus epidermidis B. Cutibacterium acnes C. Streptococcus pyogenes D. Staphylococcus aureus

D - S. aureus produces exfoliative toxin that causes staphylococcal scalded skin syndrome

How can a sufficient humoral immune response occur if a plasma cell only lives for a few days? - T cells can also produce antibodies. - Each plasma cell can produce up to 2000 antibodies every second. - Each plasma cell can proliferate into more plasma cells. - Memory B cells can also produce antibodies

Each plasma cell can produce up to 2000 antibodies every second

Pathogens and virulence factors of Bacterial Meningitis

Five species cause 90% of bacterial meningitis cases: - Neisseria meningitidis (G-, diplococci) --> Fimbriae, capsule, LPS - Streptococcus pneumoniae (G+) --> Capsule - Haemophilusinfluenzae - Listeria monocytogenes - Streptococcus agalactiae

Non-egg-based vaccines examples

Flucelvax and Flublok

Review - What are some diseases of Staphylococcus working alone?

Folliculitis and Staphylococcal Scalded Skin Syndrome (SSSS)

Assembly and Maturation of HIV

HIV that buds from a cell is nonvirulent because its capsid is not fully functional, and reverse transcriptase is inactive. ​Protease​, a viral enzyme packaged in the virion, cleaves the large polypeptide to release reverse transcriptase and capsomeres. This action of protease, which occurs only after the virus has budded from the cell, allows final maturation of the viral capsid. HIV is now active.

How do helper T-cells and cytotoxic T-cells work together? - Cytotoxic T-cells attack abnormal body cells, while helper T-cells attack virally infected cells. - Helper T-cells produce cytokines to activate other cells of the immune system. - Helper T-cells produce cytotoxic T-cells. - Cytotoxic T-cells produce cytokines to activate helper T-cells

Helper T-cells produce cytokines to activate other cells of the immune system

Coronavirus Respiratory Syndromes (SARS, MERS) Manifestations

High fever (>38°C), cough, shortness of breath

Review - Which type of antibody is produced first and in greater amounts upon subsequent exposures to an antigen (weeks, months, years, or decades after the initial exposure)? - IgE - IgM - IgG - IgA

IgG - Memory B cells result in a faster response time and larger production of IgG antibodies upon subsequent exposure to antigen.

Mouse Bioassay

In this laboratory procedure, specimens of food, feces, and/or serum are divided into two portions. Botulism antitoxin is mixed with one of the portions, and the portions are then inoculated into two sets of mice. If the mice receiving the antitoxin survive while the other mice die, botulism is confirmed.

Passive Immunotherapy using Immunoglonbulins (antibodies)

Individual acquires immunity through the transfer of antibodies formed by immune individual or animal

Prozone Phenomenon

Lack of a visible reaction in antigen-antibody combination caused by the presence of excess antibody. This may result in a false-negative reaction.

cell body

Largest part of a typical neuron; contains the nucleus and much of the cytoplasm

T cells recognize epitopes only when they are bound to __________. - CD8 molecules - MHC - other T cells - antibody

MHC - Yes. The major histocompatibility complex proteins are responsible for presenting epitope to T cells

What is the purpose of an MHC class I protein? - MHC class I molecules display epitopes from exogenous antigen. - MHC class I proteins break down endogenous antigen. - MHC class I proteins display epitopes from endogenous antigen. - MHC class I proteins bind antibodies

MHC class I proteins display endogenous antigen, including autoantigen

Why does the measles vaccine pose risks for immunocompromised contacts of immunized children?

Measles vaccine is an attenuated live vaccine; thus, it can replicate and cause disease in immunocompromised patients.

Epidemiology of Tetanus

Mortality rate is ~50% if left untreated

Bronchitis (viral or bacterial) Manifestations

Mucus-producing cough, wheezing

Clonality

Once induced, cells of adaptive immunity proliferate to form many generations of nearly identical cells, which are collectively called clones

antibodies interact with which innate defenses? -I nflammation - Phagocytosis and the complement system - The complement system - First-line defenses - Phagocytosis - Phagocytosis, inflammation, and the complement system

Phagocytosis and the complement system

In reference to clonal deletion, what are the clones? - They are the offspring or potential offspring of lymphocytes. - They are the stem cells from which all T cells are derived. - They are the cells of the thymus. - They are the T cells that undergo apoptosis.

They are the offspring or potential offspring of lymphocytes. - The clones are exact copies of lymphocytes that have been activated against a specific antigen and stimulated to divide into a large population of cells (clones).

treatment, and prevention of Eryispelas (2)

- Treat with penicillin or dicloxacillin - Prevent with proper hygiene and cleanliness

Epidemiology of Cellulitis

- Cellulitis occurs more frequently in people with poorly controlled diabetes

Virulence Factors of Pseudomonas aeruginosa of Pseudomonas Infections (7)

(Adhesins, toxins, and capsule) - Fimbriae and adhesins attach to host cells and enable biofilm formation. -- Its capsule, composed of a mucoid polysaccharide, plays a role in bacterial attachment and biofilm formation, and it shields the bacterium from phagocytosis. -- Neuraminidase modifies host cell receptor molecules to make bacterial attachment to the cells more likely. -- Elastase breaks down elastic fiber, degrades complement components, and cleaves immunoglobulins A and G (IgA and IgG). -- Endotoxin [lipopolysacharide (LPS), specifically its lipid A] can trigger fever, blood clotting, inflammation, or possibly shock. -- Exotoxin A and exoenzyme S, which inhibit eukaryotic protein synthesis, lead to host cell death. -- Pyocyanin, the blue-green pigment of Pseudomonas, triggers the formation of reactive forms of oxygen (superoxide radical and peroxide anion) that damage host cells.

Review - In which areas of the United States is plague endemic? A. In the Midwest. B. On the Eastern Seaboard. C. In western states. D. Plague is not endemic in the United States.

C

Steps of Activation of Tc (Cytotoxic T) Cell Clones and Their Functions (BOOK)

1. Antigen presentation - APCs present epitopes in conjunction with (MHC II to Helper T cells) OR with (MHC I to Cytotoxic T cells) - immunological synapse; Tc binds to dendritic cell - CD8 glycoprotein of the Tc cell, which specifically binds to MHC I protein, stabilizes the synapse 2. Helper T cell differentiation - nearby CD4-bearing helper T (Th) lymphocyte assists by binding to MHC II on the dendritic cell via the TCR of the helper cell - Association with a helper T cell induces the APC to more vigorously signal the Tc cell - Infected APCs secrete IL-12, which causes helper T cells to differentiate into Th1 clone cells - Th1 cells in turn secrete IL-2 - Lacking the assistance of Th cells, an immunological synapse between the APC and the Tc cell fails --> This limits improper immune responses 3. Clonal expansion - Signaling from the APC and IL-2 from the Th1 cell activate Tc cells that recognize the MHC I protein-epitope complex - IL-2 triggers Tc cells to divide, forming a clone of active Tc cells as well as memory T cells (clonal expansion) 4. Self-stimulation - Active Tc cells secrete IL-2, becoming self-stimulatory - no longer require either an APC or a helper T cell - They leave the lymph node and are now ready to attack virally infected cells

Steps of Immunoblot

1. Electrophoresis 2. Blotting 3. Immunoassay

Life Cycle of Chlamydia

1. Elementary body (EB) attaches to receptor on host cell (0 hrs) 2. EB triggers its own endocytosis by host cell 3. EB converts body (RB) within vesicle (10 hrs) 4. RB divides rapidly resulting in multiple RBs. The vesicle is now called an inclusion body. 5. Most RBs convert back into EBs (21 hrs) 6. EBS are released from host cell (40 hrs) 1. cycle repeats

Type B Blood

B-Antigens Anti-A antibodies Donates to B or AB Receives from B or O

Primary immunodeficiency diseases: - are sometimes caused by severe stress. - develop later in life. - may be caused by malnutrition. - are never associated with genetic defects. - are detectable close to birth.

are detectable close to birth.

What is the reason for the delayed response in a type IV hypersensitivity? A. Antibodies must travel to the location of the antigen. B. It takes macrophages and T cells time to travel to the site of the antigen. C. It takes time for antibodies to be activated at the site of the antigen. D. The antigens have to travel through the body toward the lymph nodes for the reaction to occur.

B. - Macrophages and T cells must migrate to the location of the antigen, which takes time.

Review - Which tissue does mumps virus infect? A. Liver. B. Intestinal cells. C. The salivary gland tissue. D. Epithelial cells near the lips.

C

Antibodies (3)

- immunoglobulins similar to BCRs - Secreted by activated B cells called plasma cells - Identical antigen-binding sites and antigen specificity as the BCR of the activated B cell

On the skin, where are bacteria particularly abundant? (3)

- in crevices around hairs - in the ducts of glands - they're usually nonpathogenic

Tom has a genetic disorder in which he does not synthesize class I MHC proteins or functional NK cells. Which of the following statements would be true for Tom? - Tom would not be able to produce antibodies against viruses. - Tom would not be able to destroy virally-infected cells. - Tom would be more susceptible to bacterial infections. - Tom would be less susceptible to helminth infections

Tom would not be able to destroy virally-infected cells.

Cause of Chickenpox and Shingles

varicellovirus (varicella-zoster virus, VZV) (enveloped, double-stranded DNA virus)

What are the most common intracellular pathogens?

viruses

An individual suddenly experiencing increased stress in his or her life may have a temporary deficiency in which of the following areas of the immune response? - complement activation - humoral immunity - the phagocytic response - cell-mediated immunity

cell-mediated immunity - Increased levels of stress result in elevated levels of corticosteroids, which kill T cells, resulting in secondary immunodeficiency diseases such as recurrent cold sores caused by herpes simplex viruses.

fragment C5a

chemotactic, attracting phagocytes to the site of infection

hygiene hypothesis

children exposed to environmental antigens—such as dust mites, molds, parasitic worms, and pet hair—are less likely to develop allergies than children who have been sheltered from common environmental antigens

Because an antigen (e.g., a bacterial protein) typically has numerous epitopes of various shapes, many different BCRs will recognize any particular antigen, though each BCR recognizes only one epitope of that antigen. T/F

true

MHC class II glycoproteins are expressed only by B cells and special antigen-presenting cells (APCs). T/F

true!

Scientists have not shown any connection between acne and diet, including chocolate and oily foods—foods do not affect sebum production. T/F

true!

Some doctors recommend that patient refrain from taking taking fever-reducing drugs unless the fever is prolonged or extremely high. T/F

true!

ciliary escalator

- A ciliated mucous membrane lines the trachea, bronchi, and bronchioles - cilia beat synchronously about 1000 times per minute to carry mucus and trapped contaminants up to the pharynx

Diagnosis, Treatment, and Prevention of Cat Scratch Disease (3)

- A positive indirect fluorescent antibody test against Bartonella antigens confirms a diagnosis of cat scratch disease in individuals who exhibit the characteristic signs and symptoms following exposure to cats - antimicrobials—often azithromycin - avoiding cat-inflicted wounds and adequate cleansing of bites or scratches that do occur

Hansen's Disease

- AKA "leprosy" - 2 manifestations depending on the patient's immune system (tuberculoid and lepromatous)

Microbiome of the Lower Respiratory System

- Ciliary escalator, antibodies, and phagocytic cells make the LRS axenic.

Acute Inflammation (7)

- Develops quickly and is short lived - Typically beneficial - results in the resolution of whatever condition precipitated it - Important in the second line of defense --> Dilation and increased permeability of the blood vessels --> Migration of phagocytes --> Tissue repair

Diagnosis, treatment, and prevention of Poxviruses (5)

- Diagnosis based on characteristic poks, concentrated on face and limbs - Treatment requires immediate vaccination to prevent disease from progressing --> Disease prevented if vaccine given in first 3 days - Vaccination discontinued in 1972 in the U.S. - tecovirimat, an antiviral that works against orthopoxviruses, should smallpox ever reemerge

Diagnosis, treatment, and prevention of Hantavirus Pulmonary Syndrome (HPS)

- Diagnosis made based on characteristic symptoms - No pharmacological treatment is available - Prevention requires control of rodents

Epidemiology of amebiasis

- E. histolytica is carried asymptomatically in the digestive tracts of roughly 10% of the world population - Infection arises following consumption of contaminated water or food, ingestion from contaminated hands, or during oral-anal intercourse. - Cockroaches and houseflies can facilitate the spread of cysts under conditions of overcrowding

Epidemiology of Malaria

- Endemic throughout tropics and subtropics

Epidemiology of Peptic Ulcers

- Fecal-oral transmission is likely --> Hands, well water, or fomites - Stress may worsen ulcer symptoms

Pathogens of Malaria

- Four Plasmodium species cause malaria - P. malariae, P. ovale - P. vivax: latency in liver - P. falciparum: causes most severe malaria - Disease severity depends on the species - Reproductive cycle in RBC hides pathogen from immune system - Alters body smell to attract more mosquitos

Pathogenesis and Epidemiology of Histoplasmosis

- H. capsulatum is an intracellular parasite that, upon inhalation, first attacks alveolar macrophages in the lungs. - infected macrophages disperse the fungus beyond the lungs via the blood and lymph - Cell-mediated immunity eventually develops, clearing the organism from healthy patients - People inhale spores that have become airborne when soil containing the fungus is disturbed by wind or by human activities

Prevention of Folliculitis (4)

- Hand antisepsis - proper cleansing of wounds and surgical openings - attention to aseptic use of catheters and indwelling needles - Proper antiseptic procedures in hospitals to minimize MRSA (Methicillin-resistant S. aureus) infections

Tetherin (not in book; professor notes) (picture)

- Induced by IFN α and β; part of antiviral response in neighboring cells - Impairs release of many enveloped viruses

Review - What are the components of the upper respiratory system?

- Nose - Nasal cavity - Pharynx - Tonsils - Mucus

ganglion

- Outside the CNS, a collection of many neurons' cell bodies

Primary Immunodeficiency Diseases - type of immunodeficiency diseases (2)

- Result from some genetic or developmental defect - Develop in infants and young children

3 coronaviruses

- Severe acute respiratory syndrome (SARS) - Coronavirus disease 2019 (COVID-19) - Middle East respiratory syndrome (MERS) - High fever, shortness of breath, and difficulty breathing - Later develop dry cough and pneumonia

Common Cold

- Sneezing, runny nose, congestion, sore throat, malaise, and cough - Enterovirus rhinovirus (+ssRNA) - Numerous other viruses cause colds

Influenza

- Sudden fever (39-41ºC, 102-106ºF) - Pharyngitis, congestion, dry cough, myalgia, malaise, headache

How does the 2nd line of defense differ from the first? (3)

- The 2nd line includes no barriers - instead it is composed of cells (especially phagocytes), antimicrobial chemicals (peptides, complement, interferons), and processes (inflammation, fever) - some cells/chemicals from the 1st line play roles in the 2nd line

Diagnosis of Gas Gangrene (2)

- The appearance of gas gangrene is usually diagnostic by itself - the detection of large Gram-positive bacilli is confirmatory

Attenuated (modified live) vaccines (PROF NOTES)

- Use pathogens with reduced virulence - Can result in mild infections - Active microbes stimulate a strong immune response - Can provide contact immunity --> EX: oral polio vaccine; individuals 'shed' live vaccine virus in their feces for a few days, 25% of individuals that come into contact become immune - Modified microbes may retain enough residual virulence to cause disease in susceptible individuals

Zoonosis

- a disease of animals that can transfer to humans under normal conditions

Adhesion - 2nd Stage of Phagocytosis (2)

- at infection site, phagocytes attach to microbes by binding their complementary chemicals (glycoproteins) - some bacteria have virulence factors that hinder adhesion by phagocytes (slippery capsules!!)

Neutrophils and Eosinophils (2)

- both phagocytize pathogens - both capable of Diapedesis

Cytotoxic T lymphocyte, TC(CD8 cell) (4)

- distinguished by copies of its own unique TCR - distinguished by the presence of CD8 cell-surface glycoproteins - directly kill other cells - CD8 only binds to MHC I

Cutaneous Mycoses

- fungal infections that occur in deeper skin layers - Some fungi that grow in the skin; manifest as cutaneous lesions - Ex. Dermatophytosis

Isografts (3)

- grafts transplanted between two genetically identical individuals (identical siblings or clones) - Because these individuals have identical MHC proteins, the immune system of the recipient cannot differentiate between the grafted cells and its own normal body cells --> isografts are not rejected

Wound Botulism

- growth of the bacterium in dead tissue following introduction of endospores into wounds - Signs and symptoms are similar to those of the foodborne disease, but the incubation period is longer—four days or more

Osteomyelitis

- inflammation of the bone and its internal bone marrow - in kids it typically occurs in areas with well-developed blood supply - in adults it's more commonly seen in vertebrae

Gingivitis

- inflammation of the gums - a form of Periodontal disease --> inflammation and infection of the tissues surrounding and supporting the teeth

Examples of PAMPs (3)

- lipopolysaccharide - peptidoglycan - flagellin

Autoimmunity Affecting Nervous Tissue

- multiple sclerosis

Review - What are the first phagocytes to arrive at the site of infection? (3)

- neutrophils - followed by monocytes - monocytes leave the blood and become wandering monocytes (major component of pus)

Can leprosy be cultured in a lab?

- no - In the US we use nine-banded armadillos which have a normal body temperature of 30°C - In Europe, these bacteria are endemic in red squirrels

Pneumocystis pneumonia (PCP)

- often diagnostic for AIDS - increasing difficulty in breathing, mild anemia, hypoxia (low tissue oxygen), and fever - possible nonproductive cough - Rarely, extrapulmonary lesions develop in the lymph nodes, spleen, liver, and bone marrow

What happens when an antigenic epitope binds to a specific B cell via its BCR? (3)

- the B cell is activated (becomes Plasma cell) - the B cell undergoes cell division - its offspring secrete immunoglobulins which act against the same epitope that activated the B cell

Trachoma

- the leading cause of nontraumatic blindness in humans - disease in which the conjunctiva and cornea are scarred by bacterial infection, leading to blindness

Complexity of Antigens

- the more complex, the more Epitopes - Ex. glycoproteins and phospholipids

Wounds (7)

- trauma to any tissue of the body - Cuts, abrasions, scrapes, surgery, inoculations, bites, and other penetrating skin wounds, as well as burns --> breach the significant mechanical barrier provided by intact epidermis and dermis, allowing microbes to infect the warm, moist, deeper tissues of the body - microbes can multiply, producing enzymes and toxins that enhance their growth to the detriment of the host - Dirty wounds provide platforms for the growth of microbes and development of biofilms - Can result in severe or fatal diseases - In most cases other body defenses eliminate infection (phagocytosis, complement, and inflammation)

Treatment of West African trypanosomiasis

- treat early stages with pentamidine and prescribe eflornithine or fexinidazole to treat later stages

The role of Helicobacter pylori in the formation of ulcers

1. Helicobacter pylori neutralizes stomach acid, invades the mucus, and attaches to gastric epithelial cells. 2. Helicobacter, its toxin, and inflammation cause the layer of mucus to become thin. 3. Gastric acid destroys epithelial cells and underlying tissue.

Review - Which mycosis can form lesions along a lymphatic vessel? A. Phaeohyphomycosis. B. Sporotrichosis. C. Chromoblastomycosis. D. Dermatophytosis.

B - Sporotrichosis is a fungal infection that can enter the body's lymphatic system and form skin lesions along the lymphatic vessels.

Review - Which life stage of Chlamydia trachomatis attaches to host cells and infects them? A. An inclusion body. B. A reticulate body. C. An elementary body. D. An initial body

C - An elementary body attaches to a receptor on the host cell.

Disease at a Glance - Tetanus

Cause -- Clostridium tetani (anaerobic, endospore-forming, Gram-positive rod). Virulence factors -- Endospores allow bacterium to survive harsh conditions and resist antimicrobial drugs; neurotoxin tetanospasmin blocks action of inhibitory neurons. Portal of entry -- Endospores enter through breaks in the skin, such as cuts and punctures. Signs and symptoms -- Tightening of the jaw and neck muscles, difficulty swallowing, followed by fever and muscle spasms. Incubation period -- Five days to 15 weeks (average of seven days). Susceptibility -- Unimmunized individuals with broken skin who contact the microbe. Treatment -- Cleansing of wound, administration of human tetanus immunoglobulin (HTIG) and penicillin, and active immunization. Prevention -- Tetanus toxoid contained in DTaP, DTP, and Td vaccines.

Disease at a Glance - Respiratory syncytial virus (RSV) infection

Cause -- Respiratory syncytial virus (RSV) (Pneumovirus, enveloped, negative, single-stranded RNA (-ssRNA) virus). Virulence factors -- Attaches to and enters human cells; intracellular replication cycle evades immune system; virus causes infected cells to fuse with their neighbors, so virus spreads without entering blood. Portal of entry -- Inhalation. Signs and symptoms -- Fever, rhinorrhea, coughing, cyanosis. Incubation period -- Four to six days. Susceptibility -- Babies and the immunocompromised are most at risk of serious infection. Treatment -- Supportive respiratory care; antibodies against RSV and inhaled ribavirin may slow the disease. Prevention -- Delay infection of newborns by proper aseptic technique, particularly handwashing.

Diagnosis of Necrotizing Fasciitis

Early diagnosis is difficult because symptoms are nonspecific (e.g. cellulitis also causes inflammation)

Immune cells that secrete cytokines and activate other immune cells are: - Cytotoxic T-cells - Invading pathogenic bacteria - Virally infected cells - Helper T-cells - Abnormal body cells

Helper T-cells

Toxins and bacterial parts are considered _____ antigen because they are present outside of the body's cells. - exogenous - endogenous - epitopes - autoantigen

exogenous - Exogenous antigen is present outside of our body's cells and become internalized during processing

Structures of the Cardiovascular System - Prof Notes

• Cardiovascular system composed of heart, blood, and blood vessels • Heart pumps blood into arteries connected via capillaries to veins - Arteries carry blood away from the heart - Veins carry blood to the heart • Blood composition - Serum: liquid part of blood - Formed elements: erythrocytes, leukocytes, platelets

Classical Pathway of Complement Activation (3)

- Antibodies bind to invading organisms (antigens) - binding begins a series of enzyme activities called a complement cascade - Complement proteins bind to the antigen-antibody complexes (complement fixation)

Malaria Signs and Symptoms

- Associated with parasite's life cycle within erythrocytes - Fever and chills occur on a 2- to 3-day cycle - Anemia, weakness, and fatigue gradually occur - patients suffer jaundice, severe recurrent fever and chills, headache, vomiting, and diarrhea - Historically, physicians prescribe antimalarial drugs, but strains of Plasmodium have developed resistance to many of these drugs

How do Humoral and Cell-Mediated Work Together?

- B cells secrete antibodies to prevent attachment - Tc cells will kill infected cells

Pathogen and Virulence Factors of inhalation anthrax

- Bacillus anthracis, a Gram-positive, endospore-forming, aerobic, rod-shaped bacterium - In the body, B. anthracis forms a protective capsule of glutamic acid, which inhibits phagocytosis by alveolar macrophages - bacterium also secretes anthrax toxin, which kills human cells and triggers edema (swelling due to fluid accumulation)

Pathogen and Virulence Factors of Cat Scratch Disease (3)

- Bartonella henselae is a Gram-negative aerobic bacillus (rod-shaped) - Virulence Factor is Endotoxin [lipopolysacharide (LPS), specifically its lipid A] found in the outer membrane of Gram-negative bacteria - Bartonella can grow and reproduce inside red blood cells and in cells lining blood vessel walls.

Booster doses are required to achieve full immunity after inactive vaccines. Why? (4)

- Because the microbes of inactivated vaccines cannot reproduce, they do not present as many antigenic molecules to the body as do live vaccines - inactivated vaccines are antigenically weak - they're administered in high doses or in multiple doses - some incorporate adjuvants to help

Two variants of Cryptococcus neoformansis of Cryptococcal meningitis

- C. neoformans var. gattii primarily infects immunocompetent individuals - C. neoformans var. neoformans predominantly infects immunocompromised hosts --> 50% of all cryptococcal infections

Prevention of Chickenpox and Shingles (3)

- CDC recommends an attenuated vaccine for children - a single dose of a more potent attenuated vaccine for adults 19-49 who had chickenpox as children - 2 doses of the latter for adults without chickenpox immunity

Pathogenesis of Cat Scratch Disease (4)

- Cat scratches or bites, particularly wounds by kittens, introduce the bacterium into the skin - Blood-sucking arthropods such as fleas may also transmit the bacterium from cats to people - In the skin, the bacterium grows intracellularly - Bartonella releases endotoxin when it dies, which can trigger fever, blood clotting, inflammation, and possibly shock

Pathogen and virulence factors of African Sleeping Sickness

- Caused by Trypanosoma brucei subspecies: --> East Africa: T. b. rhodesiense ---> most virulent; zoonotic; East African trypanosomiasis is rarer in humans --> West Africa: T. b. gambiense ---> longer-lasting and chronic West African trypanosomiasis - Kinetoplastid that evades immune system by changing surface glycoproteins - Transmitted via bite of Glossina with an infected salivary gland.

Pathogen and Virulence Factors of American Trypanosomiasis (Chagas' Disease)

- Caused by Trypanosoma cruzi --> flagellated protozoan - Endemic throughout Central and South America - Most mammals can harbor T. cruzi --> Opossums and armadillo - Lives inside host cells, changes surface antigens, suppresses production of immune cytokines - Transmission occurs through the bite of insects—true bugs in the genus Triatoma --> bloodsucking bugs feed preferentially from blood vessels in the lips, giving the bugs their common name—kissing bugs

Pathogens of Coccidioidomycosis

- Coccidioides immitis and C. posadasii are dimorphic soil fungi in the division Ascomycota

Dermis (4)

- Collagen fibers help skin resist abrasions - NONSPECIFIC - BVs in dermis deliver defensive cells and chemicals - dermal cells secrete antimicrobial peptides

Pathogen and Virulence Factors of Cryptococcal meningitis

- Cryptococcus neoformansis causative agent --> spherical, single-celled fungus that reproduces sexually with basidiospores --> lives in soil, the feces of birds, and the sap of eucalyptus trees --> Two variants of the yeast found worldwide --> Dimorphic fungus; can exist in form of mold or yeast - the yeast can produce melanin which appears to inhibit phagocytic killing mechanisms - Resists phagocytosis by defensive cells (polysaccharide capsule)

Acquired Immunodeficiency Diseases - type of immunodeficiency diseases (3)

- Develop as direct consequence of some other recognized cause --> malnutrition, severe stress, or infectious disease - Develop in later life

Diagnosis, treatment, and prevention of Tapeworm Infestations

- Diagnosed by presence of proglottids in fecal sample - Treated with single dose of niclosamide or praziquantel. Remove orally or pass naturally. - Prevention relies on thorough cooking of meats

Diagnosis, treatment, and prevention for Rocky Mountain Spotted Fever (9)

- Diagnosed from serological testing --> latex agglutination or fluorescent immunoassays are used to confirm an initial diagnosis based on sudden fever and headache following exposure to hard ticks plus a rash on the soles or palms --> Nucleic acid probes of specimens from rash lesion provide specific and accurate diagnosis - early diagnosis is crucial - Treat by removing the tick - Doxycycline is the preferred treatment for adults --> Chloramphenicol for children and pregnant women - Effective vaccine is not available - Prevented with use of tick repellants and avoidance of tick-infested areas

Diagnosis, treatment, and prevention of Plague

- Diagnosis based on characteristic symptoms - Must be diagnosed and treated immediately - Treated with various antimicrobial drugs --> preferably streptomycin or doxycycline - Prevented with rodent and flea control and good hygiene - Vaccine in the works but not yet complete

Diagnosis, Treatment, and Prevention of Cytomegalovirus (CMV)

- Diagnosis of CMV-induced diseases is dependent on laboratory procedures that reveal the presence of abnormally enlarged cells and inclusions within the nuclei of infected cells - Viruses and antibodies against them can be detected by ELISA tests and DNA probes - Treatment for fetuses and newborns with complications of CMV infection is difficult because in most cases the damage is done before the infection is discovered - Interferon, anti-CMV gammaglobulin, and nucleotide analogs, such as ganciclovir, slow the release of CMV from adults but do not affect the course of disease - Abstinence, mutual monogamy, and use of condoms reduce the chance of infection by CMV - organs harvested for transplantation can be made safe by treatment with monoclonal antibodies against CMV, which passively reduces the CMV load before the organs are transplanted - NO VACCINE

Outcomes of Fever (4)

- Enhances effects of interferons - Inhibits growth of some microbes - Sequestration of iron - May enhance the activities of phagocytes, cells of specific immunity, and the process of tissue repair

Pathogens and virulence factors of Influenza

- Genera: Influenza virus A and Influenza virus B --> -ssRNA - Mutations in the glycoprotein spikes hemagglutinin and neuraminidase produce new strains --> Hemagglutinin (HA)- bind to sialic acid on cells --> Neuraminidase (NA)- cleaves host sialic acid so new virions can bud from host cell

Pathogenesis of Hantavirus Pulmonary Syndrome (HPS)

- Hantavirus travels throughout body via the blood - Infection causes widespread inflammation leading to shock. 50% of patients drown in their own fluids even with intensive care.

Dental Caries, Gingivitis, and Periodontal Disease Pathogenesis

- Hard deposits, tartar or dental calculus, form when calcium salts mineralize plaque. - Plaque formation at the base of teeth triggers inflammation, leading to gingivitis. - Inflammation causes oxygen-free pockets to be formed, promoting the growth of Porphyromonas gingivalis. - P. gingivalis secretes proteases that breakdown gingival tissue, degrade bone, and promote tooth loss.

Helminthic Infestations of the Intestinal Tract

- Helminths are macroscopic, multicellular worms - Helminths can infest the GI tract as non-disease-causing parasites - Tapeworm is the common name for a cestode --> Flat, segmented, parasitic helminth --> Tapeworms are intestinal parasites that lack their own digestive system - 4 million Americans are currently infected with a roundworm - Helminths require a high protein diet

2 Types of Adaptive Immune Responses

- Humoral/Antibody - Cell-mediated - both paths stimulate and regulate innate immunity - both act directly against the specific pathogen that initiated the adaptive response

Epidemiology of Bacterial Meningitis

- Not spread by casual contact - Meningococcal meningitis can become epidemic

American Trypanosomiasis (Chagas' Disease)

- Swelling at infection site in followed by nonspecific symptoms in 1% of patients for 4-8 weeks - Chronic manifestations can occur 10-20 years after infection - Patients may develop difficulty in swallowing, severe constipation, an irregular heartbeat, and fatal congestive heart (but not every patient develops these chronic manifestations)

TLR Examples (2)

- TLR3 binds to double-stranded RNA from viruses such as West Nile virus - TLR2 and TLR6 in conjunction bind to lipoteichoic acid—a component of Gram-positive cell walls

Immune Complexes (6)

- The formation of complexes of antigen bound to antibody - initiates several molecular processes, including complement activation - normally removed from the body via phagocytosis - SMALL IMMUNE COMPLEXES ESCAPE PHAGOCYTOSIS IN TYPE 3 HYPERSENSITIVITY - circulate in the bloodstream until they become trapped in organs, joints, and tissues (such as the walls of blood vessels) - react with complement, resulting in inflammation, and cause neutrophils to release enzymes that damage nearby tissues

How are graft types named?

- according to the degree of relatedness between the donor and the recipient - autograft - isograft - allograft - xenograft

Dental Caries

- cavities

Pseudomembranous colitis

- inflammation of the colon, which is covered by a membrane consisting of connective tissue and dead/dying cells - condition is the last state of C. diff-associated diarrhea - life-threatening condition involves inflammation, more than 10 bloody stools per day, and formation of intestinal lesions called pseudomembranes, which are composed of connective tissue, dying leukocytes, and dead colon cells

Epidemiology of Primary Atypical (Mycoplasmal) Pneumonia

- nasal secretions spread M. pneumoniae among people in close contact - uncommon in young children and older adults - the most common form of pneumonia seen in high school and college students - not a reportable disease and is difficult to diagnose, so the actual incidence of infection is unknown

Ottis Externa (2)

- painful Pseudomonas infection of the external ear canal - AKA "swimmer's ear)

Review - Which type of antibody produced by a mother can protect her unborn baby? A. IgG. B. IgM. C. IgA. D. IgD.

A - IgG antibodies are the only antibodies that can traverse the placenta to protect an unborn baby. Among the five classes of antibodies, IgG antibodies are the only ones that can traverse the placenta to protect a fetus.

Review - Which of the following is the most common sexually transmitted pathogen in the United States? A. Human herpesvirus 2. B. Treponema pallidum. C. Human papillomavirus. D. Neisseria gonorrhoeae..

C

Which enzyme from Streptococcus pyogenes interferes with phagocytosis during necrotizing fasciitis? A. Streptokinase. B. Exotoxin A. C. M protein. D. Streptolysin.

C - M protein interferes with phagocytosis of the bacteria that cause necrotizing fasciitis.

Disease at a Glance - Mumps

Cause -- Mumps virus (enveloped, helical, unsegmented, negative, single-stranded RNA virus of genus Rubulavirus). Virulence factors -- Adhesins, intracellular replication cycle. Portal of entry -- Mucous membranes of the upper respiratory tract. Signs and symptoms -- Parotitis (swelling of the parotid salivary glands), face pain, fever, headache, and sore throat are the most common symptoms. Some infections may be asymptomatic. Incubation period -- 12-24 days. Susceptibility -- Unimmunized individuals are at risk. Treatment -- Comfort care only, including hot or cold packs, soft foods, fluids, and warm-water gargles. Prevention -- MMR vaccine.

Disease at a Glance - Cholera

Cause -- Vibrio cholerae (comma-shaped Gram-negative bacillus). Virulence factors -- Type III secretion system, enterotoxins; cholera toxin. Portal of entry -- Ingestion of contaminated water or raw/undercooked seafood. Signs and symptoms -- Sudden onset of "ricewater" diarrhea, dehydration (dry skin, excessive thirst, rapid yet diminished pulse, lethargy, sunken eyes), abdominal cramps, nausea, and vomiting. Death can occur within hours; the mortality rate is 25-50% in untreated patients, reduced to 1% with treatment. Incubation period -- Generally two to three days, although an infected person may show symptoms in a few hours in some cases. Susceptibility -- Humans living in endemic areas, especially in poverty-stricken areas; children tend to be affected more than adults are. Treatment -- Fluid and electrolyte replacement and administration of doxycycline. Prevention -- When in endemic areas, boil water, eat only cooked food (especially seafood), avoid raw vegetables and fruit, and wash hands frequently. A vaccine against Vibrio cholerae is available.

Disease at a Glance - Bacterial Diarrhea

Causes -- Primarily Escherichia coli, Shigella spp., Campylobacter jejuni (Gram-negative bacilli), and Clostridioides difficile (Gram-positive, anaerobic, endospore-forming bacillus). Virulence factors -- Adhesins, enterotoxins, Shiga toxin, ability to evade phagocytosis, ability to move between adjoining cells (Shigella), Shiga-like toxin (Escherichia), endotoxin (Gram-negative bacteria), endospore (Clostridioides). Portal of entry -- Ingestion via fecal-oral route; C. difficile normally lives in 5% of Americans. Signs and symptoms -- Abdominal cramps, bloody stools, nausea, vomiting, and diarrhea; C. difficile can additionally cause pseudomembrane formation. Incubation period -- A few hours to days or weeks. Susceptibility -- All humans are susceptible, but Gram-negative infection is generally worse in children and immunocompromised individuals; C. diff. is more prevalent in patients undergoing antimicrobial treatment. Treatment -- Rehydration via fluid and electrolyte replacement; antimicrobials may shorten the duration. Prevention -- Eat only thoroughly cooked meat products and pasteurized milk and juices; serve food piping hot; and practice good hygiene.

Review - Which pathogen causes extreme watery, colorless, odorless diarrhea, which can lead to dehydration and death within a day? A. Staphylococcus aureus. B. Salmonella enterica. C. Clostridium difficile. D. Vibrio cholerae.

D - The rapid loss of fluids can lead to shock and death within hours after onset of cholera.

acute glomerulonephritis

Some strains of GAS may spread from a site of impetigo or erysipelas into the blood (bacteremia) and thence into the kidneys

In which of the following situations would pooled antisera from human donors be a better choice for passive immunotherapy than would horse-derived antisera? - a patient receiving long-term treatment for an immunodeficiency disease - a patient suffering from botulism poisoning - a nurse being treated for a needle stick from a hepatitis B-contaminated needle - a snakebite victim

a patient receiving long-term treatment for an immunodeficiency disease - because they only occur in humans!

Which of the following OTC medications would provide the best relief of symptoms? - antibiotics - aspirin - acetaminophen - antihistamines

antihistamines - Antihistamines would counteract the histamine release from degranulation of mast cells and basophils.

The mucus of the upper respiratory system contains:

antimicrobial chemicals, including defensins, lactoferrin, and lysozyme - Defensins are antimicrobial peptides that act against Gram-positive and Gram-negative bacteria, fungi, and some viruses - Lactoferrin sequesters iron, making this important nutrient unavailable to microbial contaminants - Lysozyme breaks down peptidoglycan in the bacterial cell wall

Passive immunotherapy does not result in immunological memory. T/F

true

Chlamydias

- Gram-negative, obligate intracellular parasites - form extremely small, resistant structures called elementary bodies that act as infectious agents

Normal microbiota of the male reproductive system

- Regions above the prostate are sterile

Legionnaires' Disease

- S/S: Typical pneumonia symptoms --> If untreated pulmonary function can rapidly decrease, resulting in death of up to 50% of patients - Complications involving the gastrointestinal tract, central nervous system, liver, and kidneys are common

Hypodermis (4)

- a layer of fat cells and fibers lying beneath the dermis - not technically part of the skin; it is subcutaneous - Stored fat provides cushioning, insulation, and a ready energy source - fibers anchor the skin to the underlying tissues

Complement (picture)

- a set of serum proteins designated numerically according to their order of discovery --> 30+ proteins: C1a, C1r, C1q, C2a, C2b, C3a, C3b - initially act as opsonins and chemotactic factors - Complement activation results in lysis of the foreign cell - Indirectly trigger inflammation and fever - Complement activation (Classical pathway & Alternative pathway)

autoimmune diseases (3)

- any group of diseases that result when an individual begins to make autoantibodies or cytotoxic T cells against normal body components - Occur more often in the elderly - Are more common in women than in men

Antihistamine (2)

- block histamine receptors on blood vessel walls - can treat inflammation

Pathogen of Poxviruses (2)

- caused by Variola virus (dsDNA) (they are DNA viruses) - genus Orthopoxvirus

Cat Scratch Disease

- caused by infection with Bartonella henselae - common and occasionally serious infection in children - fever for a few days, prolonged malaise, and localized swelling at the site of infection and nearby lymph nodes for several months

Otitis Media

- middle ear infection - Streptococcus pneumoniae, an alpha-hemolytic streptococcus that lacks specific Lancefield antigens - more common in children, because a child's auditory tubes are more horizontal and have smaller diameters; thus, they are invaded and blocked more easily - treat with amoxicillin

bacteremia

- the presence of bacteria in the blood that causes illnesses - often caused by infection w/ Staphylococcus aureus OR Streptococcus pneumoniae - characterized by rapid respiration, increased heart rate, change in body temperature—below 36°C (97°F) or over 38.3°C (101°F)—and a low white blood cell count - Fever, chills, anxiety, confusion, nausea, vomiting, diarrhea, malaise - Septic shock can develop rapidly --> extremely low BP resulting from dilation of BVs triggered by bacteria or bacterial toxins --> signs include: decrease in or absence of urine output and inability to clot blood - Small hemorrhagic lesions called petechiae can develop on the trunk and lower extremities - Osteomyelitis occurs if bacteria invade the bone - can lead to lymphadenopathy - Toxemia symptoms vary depending on the toxin --> Exotoxins; inc​luding cytotoxins (which kill cells) and neurotoxins (which inhibit nerve cells) ----> Neurotoxins: botulism toxin, which prevents muscle contraction, and tetanus toxin, which prevents muscle relaxation --> Endotoxin ----> lipopolysaccharide (LPS); Lipid A

3 steps of Indirect fluorescent immunoassays

1. An antigen of interest is fixed to a microscope slide 2. The individual's serum is added and remains long enough to allow serum antibodies, if present, to bind to the antigen. The serum is then washed off, leaving the antibodies bound to the antigen (but not yet visible) - IgG from patient's serum attaches to antigens 3. Fluorescently labeled antibodies against human antibodies (anti-human antibody antibodies) are added to the slide and bind to the antibodies already bound to the antigen. - Fluroescent-labeled Anti-IgG (antiglobulin, anti-antibody) attaches to IgG of patient's serum. After the slide is washed to remove unbound anti-antibodies, it is examined with a fluorescence microscope.

Steps of Activation of Tc (Cytotoxic T) Cell Clones and Their Functions (PROFESSOR NOTES)

1. Antigen Presentation - DOUBLE activation of T cells - Th cell binds via CD4 to MHC II of APC. - Then the APC will secrete an IL-12. 2. Helper T cell Differentiation - Th cell is activated and secretes IL-2 to activate Tc cells 3. Clonal Expansion - Tc cell clone 'army' is made, a small amount remain as memory 4. Self Stimulation - Secrete IL-2 to stimulate their own proliferation and activation

Replication of HIV - Short Steps

1. Attachment 2. Entry by endcytosis 3. Uncoating 4. Synthesis of DNA 5. Integration 6. Synthesis of RNA and polypeptides 7. Release 8. Assembly and maturation (protease function)

Diseases associated with HHV-4 (EBV)

1. Lacking Cellular Immunity - as seen in AIDS patients - Oral Hairy Leukoplakia - EBV implicated, not proven - occurs in malnourished children, the elderly, AIDS patients, and transplant recipients; it is a precancerous change in the tongue 2. Poor Cellular Immunity - Children with chronic malaria have reduced resistance of EBV and results in lymphoma - Burkitt's lymphoma, Nasopharygeal cancer, Chronic fatigue syndrome, Hodgkin's lymphoma 3. Immature Cellular Immunity - asymptomatic 4. Vigorous Cellular Immunity - Infectious Mononucleosis

Review - Severe combined immunodeficiency disease (SCID)

Defect: Lack of T cells and B cells Manifestation: No resistance to any type of infection, leading to rapid death

How is excess iron stored?

Ferritin protein binds to Iron and stores it in the liver.

Review - Which technique involves performing electrophoresis of proteins followed by transfer to a membrane and binding with antibody? A. Neutralization test B. Immunoblotting, or western blotting C. Direct fluorescence antibody test D. ELISA

Immunoblotting is the labeling of proteins that are fixed to nitrocellulose membranes with antibodies.

Synthesis of DNA of HIV

Reverse transcriptase, which has been released from the capsid, synthesizes double-stranded DNA (dsDNA) using viral ssRNA as a template (look ahead ​to Figure 18.17).​​

fragment C3b

acts as an opsonin

Review - What is Type I hypersensitivity?

allergies, basically

This child has had a moderate reaction to his first bee sting. If he were to be stung again, the signs and symptoms could be severe and life-threatening due to constriction of airways. What is this systemic reaction called, and what would the treatment of choice be? - hemolysis; blood transfusions - anaphylaxis; epinephrine - purpura; calamine lotion - delayed hypersensitivity; acetaminophen

anaphylaxis; epinephrine

What is the most efficient and cost-effective method of controlling infectious disease?

immunization

Petechiae

small, dark purplish subcutaneous hemorrhages of blood vessels in the skin

Normally, complement-activating immune complexes are eliminated from the body by phagocytosis. T/F

true

Is the Primary or Secondary response stronger?

Secondary! - memory T cell outnumber the original T cells during the initial exposure - a subsequent cell-mediated immune response to a previously encountered antigen is much more effective than a primary response - this is called "Memory Response"

Opportunistic Infections Associated with AIDS

Skin: -shingles, disseminated (widespread) herpes, rare BV cancer "Kaposi's sarcoma" Nervous System - meningitis, toxoplasmosis, and Cytomegalovirus Respiratory System - tuberculosis, Pneumocystis pneumonia, histoplasmosis, and coccidioidomycosis Digestive System - chronic diarrhea, thrush, and oral hairy leukoplakia

humors

The interior of the eye is composed of two chambers filled with fluids (humors)

Inducibility

specific antigen-containing pathogen activates or induces cells of adaptive immunity

Inherited deficiencies of a single immunoglobulin class are more common than a deficiency of all classes. T/F (3)

true - IgA deficiency is the most common --> they experience recurrent infections in the respiratory and gastrointestinal tracts

Cells of adaptive immunity ONLY recognize epitopes that are bound to MHC molecules. T/F

true!

When does the second line of defense operate?

when pathogens penetrate the skin or mucous membrane

Toixoid Vaccines (PROF NOTES) (4)

- Chemically or thermally modified toxins used to stimulate immunity - Useful for some bacterial diseases - Stimulate antibody-mediated immunity - Require multiple doses because they possess few antigenic determinants

Chickenpox and Shingles

- Chickenpox characterized by lesions on the back and trunk that spread across body. --> The causative virus may become dormant and then years later reactivate to cause shingles - Shingles lesions localized to skin along an infected nerve. Pain may last after lesions are healed.

Vaccine Manufacture (3)

- Mass-produce many vaccines by growing bacteria in culture vessels - Viruses are cultured inside chicken eggs - Individuals with egg allergies must avoid some vaccines

Epidemiology of Viral Meningitis

- More common than bacterial and fungal meningitis - Exposure to a patient with meningitis may result in an infection resembling a cold but rarely causes meningitis - Patients become contagious when symptoms develop and remain contagious for up to 10 days

Dental Caries, Gingivitis, and Periodontal Disease Epidemiology

- Most adults have experienced dental caries - Diets high in sucrose increase the risk of decay - Sucrose (table sugar) is the only sugar that can be used to build dextran

Pathogen and virulence factors of Legionnaires' Disease

- Most cases caused by Legionella pneumophila --> G- pleomorphic --> aerobic, slender, pleomorphic, Gram-negative bacteria that are classified in the taxon Gammaproteobacteria --> extremely fastidious in their nutrient requirements, and laboratory media for culture of Legionella must be enhanced with iron salts and the amino acid cysteine - May infect and replicate inside amoeba, which will serve as a reservoir host. Protects from environmental stresses (e.g. chlorination)

Diagnosis, treatment, and prevention of Pertussis (Whooping Cough)

- Symptoms are usually diagnostic - Treatment is primarily supportive, once diagnosed the immune system as won but recovery depends on regeneration of lost cells. - Prevention is with the DTaP vaccine

Tuberculosis

- Symptoms not always initially apparent - Minor cough and minor fever - the leading disease killer in the world

Pathogenesis of Influenza

- Symptoms produced by released cytokines due to the immune response to the virus - Flu patients are susceptible to secondary bacterial infections --> Virus causes damage to the lung epithelium

streptococcal toxic shock syndrome (TSS)

- severe form of bacteremia with shock - a patient's blood pressure drops precipitously, often leading to dizziness, confusion, difficulty breathing, and a weak and rapid pulse - liver and kidneys may fail

Haemophilus influenzae - pathogen of bacterial meningitis

- small pleomorphic bacillus - requires heme and NAD+ for growth --> thus it is an obligate parasite, colonizing mucous membranes of humans and some animals - polysaccharide capsules that resist phagocytosis

Histoplasmosis

- the most common fungal disease affecting humans - In almost 95% of individuals, histoplasmosis is asymptomatic, subclinical, and resolves without damage - CLINICAL hisplasmosis is characterized by severe coughing with blood-tinged sputum or skin lesions - An AIDS patient with histoplasmosis often rapidly develops an enlarged spleen and liver, which can be fatal - Some patients' bodies mount a type I hypersensitivity reaction against the fungus in the eyes, producing inflammation and redness

How do NK cells kill? (2)

- they destroy target cells with proteins called perforin and granzyme - Perforin molecules form into a tubular structure in the target cell's membrane, forming a channel through which granzyme enters the cell and triggers apoptosis

Review - How do NK cell kill? (2)

- they destroy target cells with proteins called perforin and granzyme - Perforin molecules form into a tubular structure in the target cell's membrane, forming a channel through which granzyme enters the cell and triggers apoptosis

Ehrlichiosis

- tick-borne disease caused by a rickettsia - Erlichia chaffeensis, manifesting with flulike signs and symptoms - previous used to refer to human granulocytic ehrlichiosis, now called anaplasmosis

Autograft (3)

- tissues are moved to a different location within the same individual - don't trigger immune responses because they do not express foreign antigens - Ex. grafting of skin from one area of the body to another to cover a burn area or the use of a leg vein to bypass blocked coronary arteries

Review - Why do rhinoviruses typically cause only mild upper respiratory disease and do not affect the lungs? A. The temperature in the lungs is too high. B. Alveolar macrophages in the lungs prevent rhinovirus from infecting the lower respiratory tract. C. The ciliary escalator prevents the virus from entering the lower respiratory tract. D. The cells of the lower respiratory tract do not have the correct receptors.

A

Review - How are exotoxins different from endotoxins? A. Exotoxins are secreted, whereas endotoxins are part of a bacterial membrane. B. Exotoxins can cause toxemia, whereas endotoxin cannot. C. Exotoxins are not fatal, whereas endotoxin can cause toxic shock syndrome, which can be fatal. D. Exotoxins mainly affect the outer layers of the body, such as the skin, whereas endotoxin mainly affects internal organs.

A - Exotoxins are secreted, whereas an endotoxin is the lipopolysaccharide (LPS) layer of the outer membrane of Gram-negative bacteria.

Review - What is a physiological difference between truly pathogenic fungi and opportunistic fungal pathogens? A. They spread from skin lesions to the lungs. B. At room temperature, they grow as yeasts. C. At body temperature, the true fungal pathogens grow as yeasts. D. There is wide selection of effective antifungal drugs available to treat truly pathogenic infections; whereas, there is only a single drug effective against opportunistic fungi.

C

Review - What is keratitis? A. An inflammation of the retina. B. An inflammation of an eyebrow. C. An inflammation of the cornea. D. An inflammation of the sclera.

C

Review - What is the difference between droplet transmission and airborne transmission of pathogens? A. Airborne transmission involves pathogens that remain in the air for more than 1 hour, whereas droplet transmission involves pathogens that remain in the air for less than 1 hour. B. Airborne transmission involves travel through air currents, whereas respiratory droplets travel directly from the respiratory tract of one person to that of another. C. Airborne transmission involves travel of pathogens for more than 1 meter, whereas droplet transmission involves travel for less than 1 meter. D. Airborne transmission is a form of contact transmission, whereas transmission through respiratory droplets is a form of vehicle transmission.

C - During airborne transmission of pathogens, the pathogens travel further than droplet transmission. Pathogen transmission through respiratory droplets is a form of contact transmission in which pathogens are transmitted within respiratory droplets that travel less than 1 meter. Airborne transmission is a form of vehicle transmission in which pathogens travel more than 1 meter away from their source.

Review - Which of these hepatitis viruses is transmitted more commonly through the fecal-oral route? A. Hepatitis C virus. B. Hepatitis D virus. C. Hepatitis A virus. D. Hepatitis B virus.

C - Hepatitis A virus is transmitted more commonly through consumption of food contaminated with fecal material containing hepatitis A virus.

Review - Which poxvirus is considered an emerging pathogen? A. Orf. B. Cowpox. C. Monkeypox. D. Smallpox.

C - Human encroachment on the natural habitat of monkeys results in occasional transmission of monkeypox to people

Review - Who is at highest risk for permanent effects resulting from rubella infection? A. Children from birth to 1 year old. B. Pregnant women. C. Fetuses in the first half of pregnancy. D. Adolescents.

C - If a pregnant woman contract rubella during the first 20 weeks of pregnancy, the virus can infect the fetus across the placenta and cause severe birth defects.

Review - Which protein complex on the surface of cells displays epitopes of endogenous antigens? A. CD8. B. MHC class II. C. MHC class I. D. CD4.

C - MHC class I proteins bind to fragments of proteins inside the cell and display them on the cell's surface. All nucleated cells have MHC class I proteins on their surface, which display epitopes derived from endogenous antigens. In this way, an infected cell can signal cells of the immune system to indicate that it is infected by a pathogen.

Disease at a Glance - Coronavirus

Cause -- SARS- and MERS-associated coronavirus, and SARS-CoV-2 (positive, single-stranded RNA (+ ssRNA)(+ ssRNA) helical viruses). Virulence factors -- Intracellular replication cycle evades immune surveillance. Portal of entry -- Respiratory droplets enter through mucous membranes via close animal- or person-to-person contact. Incubation period -- Generally 2-7 days, up to 14 days in some cases. Susceptibility -- Studies suggest that some people are genetically more susceptible than others are. Treatment -- Treatment is mostly supportive, although studies show that antibodies against the viruses may be effective in reducing viral replication. Prevention -- Limit travel to endemic areas, use handwashing precautions, quarantine infected persons and their contacts.

Disease at a Glance - American Trypanosomiasis (Chagas' Disease)

Cause -- Trypanosoma cruzi (flagellated protozoan). Virulence factors -- Intracellular life, antigen switching, synthesis of protein that inhibits immunity. ​​​​Portal of entry -- ​​Bite of ​infected Triatoma (kissing) bug.​ Signs and symptoms -- Swelling at site of bite, fever, swollen lymph nodes, myocarditis, splenomegaly, and enlarged esophagus and colon. Following these symptoms, a chronic, asymptomatic stage may last for years before congestive heart failure occurs. Incubation period -- A few days to a few weeks. Congestive heart failure generally occurs 10-20 years following infection. Susceptibility -- People visiting or living in endemic areas, especially in poorly constructed dwellings in South and Central America. Treatment -- Early stages may be treated with benznidazole or nifurtimox. Late stages of American trypanosomiasis cannot be treated. Prevention -- Avoid sleeping in mud, thatched, or adobe houses in endemic areas, and use insect repellent.

What purpose does clonal deletion serve? - Clonal deletion destroys T cells with receptors complementary to the body's normal autoantigens. - Clonal deletion ensures that no two T cells are alike. - Clonal deletion destroys cancerous T cells. - Clonal deletion safeguards against making too many T cells.

Clonal deletion destroys T cells with receptors complementary to the body's normal autoantigens - The process of clonal deletion will eradicate any T cell generated against self, and thus any progeny (clones) that cell may have produced.

Cytotoxic T Cells

- attack infected cells directly

Review - Which is the most common cause of blindness due to infectious disease in the world? A. Neisseria gonorrhoeae. B. Naegleria fowleri. C. Staphylococcus aureus. D. Chlamydia trachomatis.

D

Review - Which is the most common protozoan parasitic disease in the world? A. Chagas disease. B. Toxoplasmosis. C. Schistosomiasis. D. Malaria.

D

Review - Which sexually transmitted pathogen causes lymphogranuloma venereum? A. Candida albicans. B. Treponema pallidum. C. Neisseria gonorrhoeae. D. Chlamydia trachomatis.

D

Review - What causes the hemorrhaging seen with African viral hemorrhagic fevers? A. Localized blood clotting limits blood clotting factors elsewhere in the body. B. Serum proteins, such as blood clotting proteins, cover up the pathogens, depleting the amount of blood clotting proteins available. C. Macrophages consume blood clotting proteins in the body. D. The virus infection damages blood vessels, which causes leakage.

A

Review - What is the difference between replication of Shigella and Salmonella in intestinal epithelial cells? A. Salmonella replicates in phagosomes (food vesicles), whereas Shigella replicates in the cytosol. B. Shigella can cause bacteremia, whereas Salmonella is usually phagocytized if it enters the bloodstream. C. Salmonella infects neighboring cells, whereas Shigella does not. D. Shigella triggers endocytosis upon attachment to intestinal epithelial cells, whereas Salmonella enters the cell directly.

A

Review - Which disease is characterized by a "bulls-eye" rash? A. Lyme disease. B. Anaplasmosis. C. Ehrlichiosis. D. Plague.

A

Review - Which life stage of an intestinal protozoan is infective? A. The cyst. B. The apicomplexan. C. The flagellate. D. The trophozoite.

A

Review - What characteristic do many important fungal pathogens have in common? A. They change growth habits in response to the environmental temperature. B. They have chitin and glucan in their cell walls. C. They are all septate. D. They are yeasts.

A - Many fungi change how they grow depending on the temperature of their environment. True fungal pathogens have in common that they are thermally dimorphic—meaning that they change their growth habit depending on the temperature of the environment. At lower temperatures (such as the ambient temperature outside the body), they grow in filamentous form; at higher temperatures (such as those in the body), they grow as yeasts. It is the yeast form that often causes disease.

Type AB Blood

A and B Antigens NO ANTIBODIES Donates to AB Receives from A, AB, B, or O * UNIVERSAL RECIPIENT *

Which of the following statements regarding the cell-mediated immune response is TRUE? - Helper T lymphocytes have no role in the activation of cytotoxic T lymphocytes. - Cytotoxic T lymphocytes interact with antibodies that have bound antigen to identify their target. - Cytotoxic T lymphocytes kill by producing hydrogen peroxide. - Cytotoxic T lymphocytes do not require antigen presentation to become activated. - A single cytotoxic T lymphocyte can kill many target cells.

A single cytotoxic T lymphocyte can kill many target cells

Oral Herpes - Which is the more likely cause of these lesions, HHV-1 or HHV-2?

Approximately 90% of oral herpes lesions are caused by human herpesvirus 1.

Glucocorticoids - Immunosuppressive Drugs (7)

Action: Anti-inflammatory; kill T cells - AKA "corticosteroids" - AKA "steroids" - immunosuppressive agents that suppress the response of T cells - inhibit T cell cytotoxicity and cytokine production - much smaller effect on B cell function - Ex. Prednisone and Methylprednisolone

Review - Which stage of the malaria parasite shows up as the ring form in blood cells? A. The merozoite. B. The sporozoite. C. The gametocyte. D. The trophozoite.

D - Trophozoites show up on blood smears as the ring form of the parasite

Tinea corporis

Agents: - Tinea corporisT. rubrum; Microsporum gypseum; M. canis Common Signs: - Red, raised, ringlike lesions occurring on various skin surfaces (tinea corporis on the trunk, tinea capitis on the scalp, tinea barbae of the beard) Source: - Can spread from other body sites; can be acquired following contact with contaminated soil or animals

Pathogenesis of Primary Atypical (Mycoplasmal) Pneumonia

Attachment of M. pneumoniae to the base of cilia causes the cilia to stop beating, and colonization eventually kills the epithelial cells. This interrupts the normal removal of mucus from the respiratory tract by the ciliary escalator, allowing colonization by other bacteria and causing a buildup of mucus that irritates the respiratory tract.

Review - How does Chlamydia trachomatis cause blindness? A. The bacteria enter the retina and cause tissue damage. B. Inflamed eyelids turn inward, such that the eyelashes scratch the cornea, causing scarring of the cornea. C. The bacteria form a biofilm over the surface of the eye. D. The bacteria enter the central nervous system and damage the optical nerve.

B

Review - What is the difference between foodborne botulism and infant botulism? A. Foodborne botulism is caused by ingestion of pathogenic bacteria, whereas infant botulism is caused by normal microbiota that overgrow. B. In foodborne botulism, the botulism toxin is ingested directly; in infant botulism, it is the bacteria that are ingested. C. The signs and symptoms of foodborne botulism are caused by the bptulism toxin, whereas those of infant botulism are caused by the tissue damage resulting from intestinal colonization of Clostridium botulinum. D. Foodborne botulism is contracted by eating contaminated food, whereas infant botulism is contracted through wound infection.

B - In infant botulism, the ingested bacterium Clostridium botulinum replicates in the intestines, where it produces botulism toxin.

Review - What is the "danger zone" in food preparation? A. A range of fecal matter concentrations in food that is likely to result in disease. B. A range of temperatures that are optimal for pathogen replication. C. A range of temperatures that is dangerous to pathogens, because it makes them easier to kill. D. A range of bacterial concentrations that is most likely to cause disease.

B - In the danger zone temperatures, pathogens divide rapidly.

Review - What effect do pyrogenic toxins have? A. They camouflage bacteria to protect them from phagocytosis. B. They cause fever. C. They lyse red and white blood cells. D. They kill cells in the throat.

B - Pyrogenic toxins stimulate leukocytes to release cytokines that stimulate fever, rash, and shock.

Jess has A- blood type, has never received a blood transfusion, and never been pregnant. Antibodies against what blood antigens could be present in Jess' blood? - B antigens - O and Rh antigens - A antigens - B and Rh antigens - O antigens

B anitgens

Central Nervous System Components

Brain - cerebrum --> the largest, upper part of the brain—controls voluntary muscles, perception, and what people commonly call "thinking." - cerebellum --> controls many involuntary body movements, such as swinging the arms while walking. - brain stem --> connects the brain to the spinal cord, has a number of functions, including control of breathing, heart rate, and blood pressure. Spinal Cord

Review - Which is the most common bacterium found in the oral cavity? A. Porphyromonas gingivalis. B. Clostridium difficile. C. Helicobacter pylori. D. Viridans streptococcus.

D - Viridans streptococci are alpha-hemolytic members of the genus Streptococcus and are the most common bacterium of the mouth

Review - Why is endotoxin likely to cause severe septicemia? A. Endotoxin is very toxic to red blood cells. B. Endotoxin suppresses the innate immune response. C. Endotoxin causes the immune system to respond strongly, resulting in damage. D. Endotoxin stimulates bacterial growth.

C - Endotoxin activates almost all innate immune responses of the body.

The alternative pathway of complement cascade activation begins with ________ binding to the surface of a microbe. - factor B - C3b - C5b - C5a - C1

C3b

Which event happens first during cytotoxic T-cell activation? - Clonal proliferation - Secretion of granzymes and perforin - Production of IL-2 and gamma-interferon receptors - CD8 binds to MHC molecules of infected cells

CD8 binds to MHC molecules of infected cells

Disease at a Glance - Caries (cavities)

Cause -- Bacteria, particularly Streptococcus mutans (Gram-positive coccus). Virulence factors -- Fimbriae and other adhesins; formation of biofilm called plaque and tartar; metabolizes sucrose into dextran; produces acid from sugars. Portal of entry -- Ingestion. Signs and symptoms -- Demineralization of tooth, resulting in pits and holes; tooth pain. Incubation period -- Acid production begins immediately. Susceptibility -- Everyone, especially people with a high-sucrose diet. Treatment -- Physical removal of plaque and tartar; filling of pits and holes. Prevention -- Avoidance of foods containing sucrose; regular tooth-brushing and flossing; fluoridation.

Measles - compared to Rubella

Causative Agent: Paramyxoviridae: Morbillivirus Primary Patients: Child Complications: Pneumonia, encephalitis, subacute sclerosing panencephalitis Skin Rash: Extensive Koplik's Spots: Present

Why do lymph nodes enlarge during an infection?

During an infection, lymphocytes multiply profusely in lymph nodes. This proliferation and swelling cause lymph nodes to enlarge.

A person who has AIDS contracts rare and often life-threatening infections because their helper T cell count is so low. Which of the following components of the immune response still respond to antigen despite the low helper T cell count? - Clonal expansion and antibody production - Activation of cytotoxic T cells - Apoptosis of infected host cells - Clonal selection of B cells

Clonal selection of B cells - B cells can still bind to antigen, which is the process of clonal selection. However, without a helper T cell, clonal expansion and antibody production will not occur.

Review - Which human herpesvirus most commonly causes cold sores, and which most commonly causes genital herpes? A. Commonly, HHV-1 causes both cold sores and genital herpes. B. Commonly, HHV-1 causes cold sores, and HHV-2 causes genital herpes. C. Commonly, HHV-2 causes both cold sores and genital herpes. D. Commonly, HHV-2 causes cold sores, and HHV-1 causes genital herpes.

Commonly, HHV-1 causes cold sores, and HHV-2 causes genital herpes.

Lymphatic Vessels

Conducts lymph from tissues and returns it to the circulatory system

Review - Why do scientists use an antibody test to reveal the presence of Leptospira interrogans in a sample? A. It is hard to see the pink-colored L. interrogans bacteria in a blood sample. B. L. interrogans is too small to be visible with a light microscope. C. L. interrogans is secreted only in very small numbers. D. L. interrogans does not stain well with the Gram stain

D

3. Immunoassay - Third Step of Immunoblot

Each nitrocellulose strip is incubated with a test solution—in this example, samples from each of six individuals who are being tested for antibodies against HIV. After the strips are washed, an enzyme-labeled anti-antibody solution is added for a time; then the strips are washed again and exposed to the enzyme's substrate. Color develops wherever antibodies against the HIV proteins in the test solutions have bound to their substrates, as shown in the positive control. In this example, the individual tested in strip 3 is positive for antibodies against HIV, whereas the other five individuals are negative for antibodies against HIV (FIGURE 17.14b). Immunoblots are sensitive and can detect many types of proteins simultaneously. Colored bands common to all patients are normal serum proteins.

Because attenuated live vaccines contain viruses that are less virulent, many booster vaccines must be given to produce an effective immune response. T/F

False

Influenza (viral) Manifestations

Fever, rhinorrhea, headache, body aches, fatigue, dry cough, pharyngitis, congestion

Review - Which bacteria makes endotoxins?

Gram-negative bacteria

Details of Attachment, Entry, and Uncoating of HIV

HIV uses gp120 and gp41 to attach to and enter target cells (FIGURE 18.16). CD4 on a target cell's cytoplasmic membrane is the receptor for gp120, that is, gp120 attaches HIV to CD4 ❶❶. The CD4-gp120 complex binds to another membrane receptor, either CCR5 or CXCR4 (also known as fusin, which triggers the cell's membrane to move out and surround the virus—a process called endocytosis ❷❷. Endocytosis forms a bubble of membrane with the virus inside. This structure is called an endosome ❸❸. HIV remains intact within an endosome for about 30 minutes. Glycoprotein 41 on the viral envelope evidently then facilitates fusion of the envelope with the endosome membrane. The two fuse ❹❹, and the viral capsid is introduced intact into the cell's cytosol ❺❺. The viral capsid uncoats, releasing viral RNA and proteins ❻❻.

Review - Sweat on the surface of the skin inhibits the growth of most pathogens. Which group of microbes can withstand the stress of living in such a sweaty habitat? A. Acidophiles. B. Psychrophiles. C. Alkalinophiles. D. Halophiles.

Halophiles can grow in the presence of salt, which is present in sweat. Halophiles can withstand the higher concentrations of salt on the surface of the skin resulting from sweat.

Review - Which type of antibody is involved in a type I hypersensitivity response? A. IgA B. IgE C. IgG D. IgM

IgE - IgE antibodies on the surface of mast cells and basophils are responsible for a type I hypersensitivity response.

Can viruses be treated with passive immunotherapy antibodies? (2)

In some cases with specific viruses! - Ex. hepatitis A and B, measles, rabies, Ebola, chickenpox, and shingles

Immune System Cytokines

Interleukins (ILs) - Signal among leukocytes; 37 Interferons(IFNs) - Antiviral proteins that may act as cytokines - inhibit the spread of viral infections - gamma interferon, (IFN-γ), which is a potent phagocytic activator secreted by type 1 helper T cells Growth factors - Proteins that stimulate stem cells to divide - body can control the progression of an adaptive immune response by limiting the production of growth factors Tumor necrosis factor (TNF) - Secreted by macrophages and T cells to kill tumor cells and regulate immune responses and inflammation Chemokines - Chemotactic cytokines that signal leukocytes to move

When a person has previously been vaccinated against a viral pathogen, which cells are activated if that same pathogen re-enters the host's cells months or years later? - Memory cytotoxic T cells - Bacterial pathogens - Memory B cells - Helper T cells

Memory cytotoxic T cells

Review - Which type of symbiotic relationship do the normal microbiota on the surface of your skin have with your body? A. Mutualism or amensalism. B. Commensalism and parasitism. C. Commensalism and amensalism. D. Mutualism or commensalism.

Mutualism or commensalism - In mutualistic relationships, both members of the symbiosis benefit from the interaction; in commensalism, one organism benefits, while the other is generally unaffected. Normal microbiota on the surface of the skin benefit from the relationship with their human host, while the human host either benefits or at least is not harmed. Microbiota on the surface of the skin normally benefit from their interaction with their human host and do not cause damage to the host. The human host benefits from the presence of normal microbiota or remains unaffected.

Is chickenpox caused by a poxvirus?

NO

Should pregnant people receive live vaccines?

NO - because of the danger that the attenuated pathogen might cross the placenta and harm the fetus

Type O Blood

NO ANTIGENS Anti- A and Anti-B antibodies Donates to A, AB, B, or O Receives from O * UNIVERSAL DONOR *

Review - Which two cells use perforin and granzyme?

Natural Killer cells and Cytotoxic T cells

Review - Which white blood cells phagocytize pathogens and subsequently die, trapping other microbes in webs of extracellular fibers? A. Basophils. B. Lymphocytes. C. Monocytes. D. Neutrophils.

Neutrophils - Neutrophils are phagocytes that engulf pathogens and then die. Upon their death, they release a web of extracellular fibers that traps other pathogens. Neutrophils are phagocytes that engulf pathogens. After a neutrophil engulfs a pathogen, it dies; its nucleus then degrades, and the nuclear content mixes with the cytoplasm, resulting in the formation of fibers. Neutrophils also produce superoxide and peroxide to commit apoptosis, after which fibers form when the cell dies. These fibers form a web that traps neighboring microbes, and the oxide radicals kill them.

Is there a cure for Type III Hypersensitivities?

No - though steroids that suppress the immune system may provide some relief

Review - Which drug can be used to cure a patient of herpesvirus? A. Acyclovir. B. No cure is possible, although some drugs can reduce shedding and limit transmission. C. Penciclovir. D. Azidothymidine.

No cure is possible, although some drugs can reduce shedding and limit transmission. - Herpesvirus infections cannot be cured completely, but nucleoside analogs can limit shedding and transmission.

Dendritic cells are phagocytic. Are they white blood cells?

No! Dendritic cells await microbial invaders, phagocytize them, and inform cells of adaptive immunity that there is a microbial invasion.

Prevention of Acne

Though cleaning the surface of the skin does not remove acne-producing bacteria (they live deep in the sebaceous glands), frequent cleansing may dry the skin, which helps loosen plugs from hair follicles.

Autoimmunity Affecting Connective Tissue (3)

Rheumatoid arthritis - type III hypersensitivity - Autoantibodies are formed against connective tissue in joints

Which of the following defense systems would be involved in eliminating virally-infected cells? - Complement system - T lymphocytes - Humoral immunity - Phagocytosis

T lymphocytes

Pathogenesis of Eryispelas

The bacteria invade where the skin is compromised

In general, what types of cells are involved in tissue repair? (picture)

Tissue repair is effected by cells that are capable of cytokinesis and differentiation. If fibroblasts are among them, scar tissue is laid down.

For some bacterial diseases such as tetanus, it is more effective to produce an immune response against the bacterial toxin than against the bacteria. T/F

True

How should you describe this skin reaction to the bee sting? - type III hypersensitivity reaction - type II hypersensitivity reaction - type IV hypersensitivity reaction - type I hypersensitivity reaction

Type I - This is a localized reaction in response to insect venom

Type I was what? Type II was what?

Type I - allergies Type II - cytotoxic (transfusion reactions, hemolytic disease of the newborn)

Type I? Type II? Type III?

Type I - immediate; allergies Type II - cytotoxic; transfusion reactions and hemolytic disease of newborn Type III - immune complex-mediated; Caused by formation of immune complexes that trigger the release of inflammatory chemicals (Hypersensitivity pneumonitis; Glomerulonephritis) (lupus; Rheumatoid arthritis)

Which of the following types of vaccines should NOT be given to pregnant women or immunocompromised individuals? - attenuated vaccines - recombinant vaccines - inactivated vaccines - toxoid vaccines

attenuated vaccines - Because they contain merely weakened forms of a particular pathogenic microbe, attenuated vaccines carry the greatest risk for the fetus or for an immunocompromised individual

Transmission of Staphylococcal Scalded Skin Syndrome (SSSS)

by person-to-person spread of the bacterium onto skin surfaces, where it penetrates cuts and abrasions

autoantibodies against muscle cells

cause muscle inflammation and, in some cases, damage to the heart

Thymus cells are specialized to participate in clonal deletion because they have the ability to __________. - express all of the body's autoantigens - undergo apoptosis - recognize MHC proteins and epitopes - express MHC proteins

express all of the body's autoantigens - Yes. Thymus cells have the ability to process all of the body's autoantigens and present them in MHC proteins.

According to the animation, B cells interact directly with - inflammation. - the complement system. - phagocytes. - helper T cells.

helper T cells

Type I hypersensitivity reactions are usually: (2)

mild and localized - Local skin inflammation may produce hives

Is AIDS a single disease?

no it's a syndrome - a group of signs, symptoms, and diseases associated with a common pathology

A person exposed to hepatitis A virus may be treated with an injection of antibody molecules. This type of treatment is: - serology. - adjuvant therapy. - immunization. - vaccine therapy. - passive immunotherapy.

passive immunotherapy

Librarian's Lung - type of Hypersensitivity Pneumonitis

results from inhaling dust from old books.

Secondary/reactivated tuberculosis

results when M. tuberculosis breaks the stalemate, ruptures the tubercle, and reestablishes an active infection. Reactivation occurs in about 10% of patients; patients whose immune systems are weakened by disease, poor nutrition, drug or alcohol abuse, or by other factors

Disseminated tuberculosis

results when macrophages carry the pathogen via blood and lymph nodes to other sites, including bone marrow, spleen, kidneys, spinal cord, and brain

Rh antigen is common to the red blood cells of humans and what?

rhesus monkeys

Which of the following is an example of a live attenuated oral vaccine recommended by the CDC for the general population: rotavirus, measles, hepatitis A, varicella-zoster?

rotavirus

The process of phagocytosis involve all of the following EXCEPT: - vesicle fusion. - secretion of cytotoxins. - adhesion. - chemotaxis. - elimination.

secretion of cytotoxins

If a T cell recognizes MHC in conjunction with autoantigens, it will either __________ or differentiate to become a regulatory T cell. - undergo apoptosis - differentiate to become a cytotoxic T cell - differentiate to become a B cell - divide into a repertoire of T cells

undergo apoptosis - Yes. If a T cell recognizes autoantigen, it must undergo apoptosis to prevent the formation of progeny and against self. This could lead to an autoimmune disease.

Lymphocytes - 3rd Line of Defense (6)

- "Adaptive Immunity" - SPECIFIC - HAVE MEMORY --> alter the body's defenses such that they act more effectively upon subsequent infection by that same specific strain (adaptive immunity is what makes vaccines work) --> must be activated by antigen-presenting cells before defense can launch - Ex. antibodies, cytotoxic cells

Phagocytosis (5)

- "cell eating" - phagocytosis is executed by phagocytes; rid the body of pathogens that have evaded the body's first line of defense - not completely understood - 5 phagocytes - can be divided into 6 stages

How does innate immunity accomplish recognition of nonself chemicals? (2)

- Certain structures are present on bacteria, fungi, and other microbes that are lacking on human cells. - These structures, called PAMPs, are critical components to the microbes and thus cannot be easily altered by mutation

Microbial Antagonism (professor notes; shorter version) (4)

- Consume nutrients - Create an environment unfavorable to other microorganisms - Help stimulate the body's second line of defense - Promote overall health by providing vitamins to host

Granulocytes (4)

- Contain large granules that stain different colors - Basophils stain blue with the basic dye methylene blue - Eosinophils stain red to orange with the acidic dye eosin - Neutrophils also known as polymorphonuclear leukocytes (PMNs), stain lilac with a mixture of acidic and basic dyes

Neutrophil Chemicals (2)

- Enzymes in a neutrophil's cytoplasmic membrane add electrons to oxygen, creating highly reactive superoxide radical O−2O2− and hydrogen peroxide (H2O2).(H2O2). Another enzyme converts these into hypochlorite, the active antimicrobial ingredient in household bleach. These chemicals can kill nearby invaders. - Yet another enzyme in the neutrophil's membrane makes nitric oxide, which is a powerful inducer of inflammation.

The thin epithelium of a mucous membrane provides a less efficient barrier than the multiple layers of dead cells found at the skin's surface. How does it keep microbes from invading?(3)

- In some cases, it doesn't keep all pathogens out! --> respiratory and reproduction systems are common portals of entry - still, tight cell packing and continual shedding prevents the entry of many pathogens

Interferons (5) (picture)

- Proteins released by host cells to nonspecifically inhibit the spread of viral infections --> lack of specificity means that interferons produced against one viral invader protect somewhat against infection by other types of viruses as well - Signals chemotaxis of most immune cells (macrophages, NK cells etc.) - Cause many symptoms associated with viral infections (muscle aches, chills, fever etc.) - Two types: --> Type I (α and β) --> Type II (γ)

Maturation - 4th Stage of Phagocytosis (2)

- a membranous organelle called a Lysosome fuses to the maturing Phagosome and adds digestive chemicals - fusion is now called a Phagolysosome

Ingestion - 3rd Stage of Phagocytosis (2)

- after adhesion, pseudopods extend and surround the microbe - the pseudopods form a food vesicle around the encompassed microbe called a Phagosome

Dermicidin - of sweat glands (4)

- antimicrobial/antifungal peptide - active against many Gram-negative and Gram-positive bacteria and fungi - insensitive to low pH and salt (as expected) - exact mechanism of action is unknown

Nonspecific Chemical Defenses Against Pathogens (7)

- assist phagocytic cells either by enhancing other features of innate immunity or by directly attacking pathogens - lysozyme - defensin - Toll-like receptors - NOD proteins - interferons - complement

Killing by Neutrophils

- can kill with/without phagocytosis - Primary "bacteria eating cell" --> first to arrive at infection site - produces chemicals from the membrane that kill nearby invaders - Generate extracellular fibers called neutrophil extracellular traps (NETs) that bind to and kill bacteria --> Unique type of cell death seen in neutrophils --> NETs composed of chromatin studded with antimicrobial proteins

Killing by Eosinophils (7)

- can phagocytize BUT it's not their usual mode of attack - instead they secrete antimicrobial chemicals against pathogens that are too large to ingest - attack helminths by adhering to the worm surface and secreting toxins that weaken and kill it - Lipopolysaccharide from Gram-negative bacterial cell walls triggers eosinophils to rapidly eject their mitochondrial DNA --> mitoDNA combines with previously extruded eosinophil proteins to form a physical barrier --> this extracellular structure binds to and then kills the bacteria -> first evidence that DNA can have antimicrobial activity

Differential White Blood Cell Count

- can signal signs of disease - Increased eosinophils indicate allergies or parasitic worm infection - Increased neutrophils and lymphocytes indicate bacterial disease - Increased lymphocytes indicate viral infection - increase of certain leukocytes over normal can indicate cancer - a decrease below normal can reveal immunodeficiency

Formed Elements

- cells and cell fragments in plasma - 3 types (erythrocytes, platelets, leukocytes)

Mucous Membrane Epithelial Shedding (2)

- cells are continually shed and replaced by Stem Cells - shedding carries attached microorganisms away

Dendritic Cells (4)

- cells of the epidermis and mucous membranes that devour pathogens - slender, fingerlike processes of dendritic cells extend among surrounding cells, forming an almost continuous network to intercept invaders - NONSPECIFIC - but are also involved in Adaptive (specific) immunity

Chemotactic Factors (2)

- chemicals, such as peptides derived from complement and cytokines, that attract cells - include defensins, peptides derived from complement, and chemicals called chemokines

Antimicrobial Peptides (8)

- defensin - positively charged chains of 20 to 50 amino acids that act against microorganisms - secreted on skin; in mucous membranes; in neutrophils - triggered by sugar and protein molecules on microbe surfaces - some punch holes in cytoplasmic membranes - some interrupt internal signaling or enzyme action - some act as chemotactic factors - some assemble to form fibers and microscopic nets that ensnare invading bacteria

Dendritic Cells of Mucous Membranes (3)

- dendritic cells reside below the mucous epithelium to phagocytize invaders - able to extend cytoplasmic extensions (pseudopods) between epithelial cells to "sample" the contents of the lumen --> helps prepare adaptive immune responses against particular pathogens that might breach the mucosal barrier

Lysozyme (3)

- destroys cell walls - cleaves bonds between sugar subunits of the peptidoglycan walls - resulting walls are more susceptible to osmotic shock and digestion by other enzymes within phagocytes

Elimination - 6th Stage of Phagocytosis (4)

- digestion is not always complete - phagocytes eliminate remnants of microorganisms via exocytosis - Phagolysosome fuses with plasma membrane and expels contents - some microbial components are specially processed and remain attached to the cytoplasmic membrane of some phagocytes, particularly dendritic cells (antigen processing and presentation) --> plays a role in the adaptive immune response

Which white blood cells DON'T kill using phagocytosis? (3)

- eosinophils - NK (natural killer) cells - neutrophils

How do humans have species resistance? (5)

- human cells and basic physiological processes are incompatible w/ structures/physiology or most plant/animal pathogens - either the receptors that the pathogens need don't exist in the human body - or the pH/temp is incompatible with pathogen requirements - Ex. humans are resistant to the Tobacco Mosaic Virus (which only affects tobacco plants) - Ex. Feline Immunodeficiency Syndrome attaches to receptors only found on cats' cells

Inflammatory Response - 2nd Line of Defense (2)

- internal - composed of protective cells, bloodborne chemicals, processes that inactivate/kill invaders

Eosinophils (3)

- involved in defending the body against parasitic worms - present in large number during many allergic reactions --> exact function in allergies is disputed

Monocyte

- large agranulocytes with slightly lobed nuclei - leaves the blood and matures into macrophages

Chemotaxis - 1st Stage of Phagocytosis (3)

- movement of a cell towards (positive chemotaxis) or away from (negative chemotaxis) a chemical stimulant - phagocytes use pseudopods to crawl toward microorganisms at a site of an infection - microbial secretions, parts of cells, components of damaged tissue, leukocytes and chemotactic factors attract phagocytes

2 Examples of Mucous Membrane Chemicals

- mucus contains antimicrobial peptides - Nasal mucus also contains lysozyme

Epidermis

- multiple layers of tightly packed cells that form a physical barrier to most bacteria, fungi, and viruses - Few pathogens can penetrate these layers - Shedding of dead skin cells removes microorganisms - Epidermal dendritic cells phagocytize pathogens

Killing by Natural Killer Lymphocytes (5)

- only lymphocyte involved in innate immunity - secretes toxins onto the surface of virally infected cells and tumors (neoplasms)] --> Triggers apoptosis and cell death - they ID and spare normal body cells because they have membrane proteins similar to those on NK cells - "NK" comes from the fact that NK cells kill other cells unless they receive an inhibitory signal

Skin (3)

- outer Epidermis; inner Dermis - physical structure and chemical components lend to an effective defense - 2 basic characteristics: barriers (tightly joined cells) and clearance (outermost cells slough off)

Sweat Glands (4)

- perspiration contains salt, antimicrobial peptides, and lysozyme --> Salt draws water osmotically from pathogens, inhibiting their growth and killing them --> Dermcidin --> Lysozyme destroys cell wall of bacteria

Macrophages - mature monocytes (7)

- phagocytic cells of the second line of defense - devour foreign objects, including bacteria, fungi, spores, and dust as well as dead body cells - often named for their location in the body, because they specialize for each body tissue - Ex. Wandering macrophages leave the blood via diapedesis and perform their scavenger function while traveling throughout the body in intracellular spaces - Ex. alveolar macrophages of the lungs - Ex. microglia of the central nervous system - Fixed macrophages generally phagocytize within specific organs

Platelets (2)

- pieces of Megakaryocytes that have split into small portions of cytoplasm surrounded by cytoplasmic membranes - Involved in blood clotting

Why are the lungs of smokers not properly cleared of mucus? (3)

- poisons and tars in tobacco smoke damage cilia - smokers may develop severe coughs as their respiratory tracts attempt to expel excess mucus - may succumb to many respiratory pathogens because they can't effectively clear out pathogens

Species Resistance

- property that protects a type of organism from infection by pathogens of other, very different organisms

NOD Proteins (6)

- receptors for microbial molecules like PAMPs - in CYTOPLASM (not membrane like TLRs) - trigger inflammation, apoptosis, and other innate immune responses against bacterial pathogens - Mutations in NOD genes are associated with several inflammatory bowel diseases (Crohn's) - bind to Gram- walls - bind to RNA viruses (AIDS, Hep C, mononucleosis)

Physical Barriers - 1st Line of Defense (3)

- skin and mucous membranes - made up of structures, chemicals, and processes that work together to prevent pathogens from entering the body in the first place - When these barriers are pierced, broken, or otherwise damaged, they become portals of entry for pathogens

How do phagocytes destroy invading pathogens but leave the body's healthy cells unharmed? (2)

- some phagocytes have receptors for microbial surface components that are LACKING on the body's cells (body cells can't bind to these!) (ex. cell wall components or flagellar proteins) - Opsonins like blood proteins or antibodies provide signals to the phagocyte

mucous membrane of the trachea

- stem cells produce both goblet cells --> secrete an extremely sticky mucus that acts as a barrier, trapping bacteria and other pathogens - ciliated columnar cell cilia propel the mucus and its trapped particles and pathogens up and away from the lungs - Mucus carried into the throat is coughed up and either swallowed or expelled (BARRIER AND CLEARANCE)

Serum

- the fluid remaining when clotting factors are removed (as when blood clots)

Considering microbial antagonism of the microbiome, why is using antimicrobial soaps bad for you?

- the human microbiome plays many roles in protecting us from infection, from inhibiting invading pathogens and training the immune system, to strengthening immune responses

Lymphocyte (4)

- the smallest leukocytes - have nuclei that nearly fill the cells - Most are involved in adaptive immunity - natural killer (NK) lymphocytes function in innate defense

Epithelial Cells of Mucous Membranes (6)

- tightly packed cells form a THIN layer --> in some areas it's only a single cell thick - surface cells are alive! (unlike skin) - Continual shedding of cells carries away microorganisms - diffuse nutrients and oxygen (digestive, respiratory, and female repro systems) - eliminate wastes (urinary, respiratory, and female repro systems)

6 Stages of Phagocytosis

1. chemotaxis (of phagocyte to microbes) 2. adhesion 3. ingestion (of microbes by phagocytes) 4. maturation (fusion of a series of vesicles including lysosomes) 5. killing (of microbes by enzymes and other chemicals) 6. elimination (exocytosis) ***process is actually continuous and doesn't proceed in a discrete step-wise manner

4 Steps of Tears

1. produced in lacrimal glands 2. exit on to through lacrimal ducts 3. enter lacrimal canal 4. exits into nose through nasolacrimal duct

How does the microbiome protect the body?

Competitive Inhibition (microbial antagonism) 1. Members of the microbiome consume nutrients, making them unavailable to pathogens 2. Microbiome can change the pH of regions of the body, creating an environment that is favorable for themselves but unfavorable to other microorganisms, such as acid in the vagina 3. Microbiome can attach to all of the sites on human cells, blocking pathogens from attaching 4. Microbiome stimulates the body's second line of defense, boosting the body's production of antimicrobial substances --> Researchers have observed that animals raised in an axenic environment—that is, one free of all other organisms or viruses—are slower to defend themselves when exposed to a pathogen 5. Members of the microbiome can themselves generate antimicrobial compounds to defend their "turf," the human body 6. Nutritionally, the resident microbiota of the intestines improve overall health by providing several vitamins, including biotin (vitamin B7)(vitamin B7) and pantothenic acid (vitamin B5),(vitamin B5), which are important in glucose metabolism; folic acid, which is essential for the production of the purine and pyrimidine bases of nucleic acids; and the precursor of vitamin K, which has an important role in blood clotting

Humans require ___ for metabolism. (4)

Iron! - component of cytochromes of electron transport chains - functions as an enzyme cofactor - essential part of hemoglobin

neutrophil extracellular traps

Neutrophils also generate webs of extracellular fibers nicknamed NETs, for neutrophil extracellular traps. Neutrophils synthesize NETs via a unique form of cellular suicide involving the disintegration of their nuclei. As the nuclear envelope breaks down, DNA and histones are released into the cytosol, and the mixing of nuclear components with membranes and proteins derived from cytoplasmic granules combine to form NET fibers. The neutrophil then kills itself using superoxide and peroxide. The dying cell releases the NETs as its cytoplasmic membrane ruptures. NETs trap both Gram-positive and Gram-negative bacteria, immobilizing them and sequestering them along with antimicrobial peptides, which kill the bacteria. Thus even in their dying moments, neutrophils fulfill their role as defensive cells.

Review - Name an antimicrobial protein found in tears

Tears contain lysozyme, an antimicrobial protein which acts against the peptidoglycan of bacterial cell walls.

Plasma Proteins

albumins, globulins, fibrinogen - inflammation, blood clotting, etc.

hematopoiesis (picture)

blood stem cells located principally in the bone marrow within the hollow cavities of larger bones produce three types of formed elements

Can viruses move across the blood-brain barrier?

yes! - Viruses, being smaller than cells, can more readily cross the blood-brain barrier; therefore, it is not surprising that there are more viral infections of the nervous system than bacterial or fungal infections - Include meningitis, polio, and rabies

Review - Which is the most common respiratory disease in newborns and young children? A. Respiratory syncytial virus infection. B. Influenza. C. Severe acute respiratory syndrome. D. Coronavirus respiratory syndrome.

A

Review - Which microbe is the most common cause of urinary tract infections? A. Escherichia coli. B. Pseudomonas aeruginosa. C. Staphylococcus aureus. D. Mycoplasma hominis

A

Review - Which of these is a fungal pathogen that can cause meningitis? A. Cryptococcus neoformans. B. Chlamydia trachomatis. C. Trypanosoma brucei. D. Neisseria gonorrhoeae.

A

Review - Why is mycoplasmal pneumonia also referred to as "walking pneumonia"? A. The symptoms are mild. B. The pathogen travels so quickly from the upper to the lower respiratory tract that it is said to be "walking" into the lungs. C. It is named after Dr. Walking, who discovered the cause of this disease. D. Patients contract this disease from walking around contagious people.

A

Viral Hepatitis

- Jaundice, abdominal pain, fatigue, vomiting, appetite loss - Symptoms may occur years after initial infection - Host immune response that kill infected cells cause most of the liver damage

Graft Rejection (4)

- "transplant rejection" - a highly destructive phenomenon that can severely limit the success of organ and tissue transplantation - a normal immune response against foreign major histocompatibility complex (MHC) proteins on the surface of graft cells - likelihood of graft rejection depends on the degree to which the graft is foreign to the recipient, which in turn is related to the type of graft

Viral Diseases of the Skin and Wounds (9)

**MANY ARE SYSTEMIC- can result in signs and symptoms in the skin - poxviruses - herpes infections - warts - chickenpox - shingles - rubella - measles - erythema infectiosum - roseola

The 10 Toll-like Receptors (picture) (4)

- 10 TLRs are known for humans - 1, 2, 4, 5, 6 are in cytoplasmic membranes - 3, 7, 8, 9 are added to phagosome membranes - some act alone, some act in pairs to recognize PAMPs

Postpolio syndrome

- 15-30 years after NPP or PP attack. - Muscle weakness, fatigue, paralysis - occurs in up to 80% of recovered polio patients some 30-40 years after their original bout with poliomyelitis - not caused by a reemergence of polioviruses, because viruses are not present - Instead, the effects appear to stem from an aging-related aggravation of nerve damage that occurred during the original infection

Killing / Phagolysosome - 5th Stage of Phagocytosis (6)

- AKA "residual body" - contain antimicrobial substances (ex. highly reactive, toxic oxygens) - pH 5.5 due to H+ intake from cytosol into phagolysosome - these substances, along with 30+ enzymes (lipases, proteases, nucleases) destroy the engulfed microbes - most pathogens die within 30 minutes of phagolysosome formation - virulence factors can hinder phagolysosome efficiency (ex. waxy cell walls of Mycobacterium)

The Complement Fixation Test - immune testing (4)

- Activation of the classical complement system by antibodies leads to the generation of membrane attack complexes (MACs) that disrupt cytoplasmic membranes - this test is a complex assay used to detect the presence of specific antibodies in an individual's serum - can detect the presence of small amounts of antibody—amounts too small to detect by agglutination - replaced by ELISA or genetic analysis using polymerase chain reaction (PCR)

3 Applications of Immunology

- Active Immunization (vaccination) - Passive Immunotherapy using Immunoglonbulins (antibodies) - Immune Testing

T-dependent antibody immunity

- Adaptive immune response resulting in immunoglobulin production that requires the action of a specific helper T cell (Th2) - Most antibody immune responses depend on interaction with helper T cells - act against molecules with multiple repeating epitopes, such as polysaccharides - TH cells secrete IL-4 to activate B cell

Treatment of Type I Hypersensitivity (7)

- Administer drugs that counteract inflammatory mediators --> Antihistamines neutralize histamine - Treat asthma with a corticosteroid (inhalant containing glucocorticoid) and a bronchodilator - Epinephrine neutralizes many mechanisms of anaphylaxis --> Relaxes smooth muscle --> Reduces vascular permeability --> Used in emergency treatment of severe asthma and anaphylactic shock

Active Immunization (vaccination) (2)

- Administration of antigens so patient actively mounts a protective immune response - Prevents disease, not infection

Passive Immunotherapy - how does it work? (5)

- Administration of antiserum containing preformed antibodies - used when protection against a recent infection or an ongoing disease is needed quickly --> achieved because passive immunotherapy does not require the body to mount a response --> preformed antibodies are immediately available to bind to antigen, enabling neutralization and opsonization to proceed without delay - Ex. used against botulism poisoning by Clostridium botulinum; passive immunotherapy with preformed antibodies against the toxin can prevent death

Pathogenesis of Zika Virus

- Aedes aegypti mosquito is the primary vector for Zika virus - can also be sexually transmitted vaginally, orally, or anally - can spread from pregnant women across the placenta to infect neural stem cells in unborn children, particularly if the woman is infected during the first trimester --> infection of a fetal brain results in cell death, thinning of the brain tissue, and microencephaly. - Part of the Zika virus genome binds preferentially to an RNA-binding protein that is highly expressed in neuron stem cells. The interaction of the virus with this protein may cause the congenital abnormalities associated with Zika virus

Pathogenesis and Epidemiology of Cytomegalovirus (CMV)

- Bodily secretions, including saliva, mucus, milk, urine, feces, semen, and cervical secretions, carry CMV - Individual viruses are not highly contagious, so transmission requires intimate contact involving a large exchange of secretion - Transmission usually occurs via sexual intercourse but can result from in utero exposure, vaginal birth, blood transfusions, and organ transplants - one of the more common infections of humans - CMV infects about 50% of the adult population of the United States - Like other herpesviruses, CMV becomes latent in various cells, and infection by CMV typically lasts for life

Inactivation of Complement (2)

- Body's own cells withstand complement cascade --> Proteins on many cells bind and break down activated complement proteins

Pathogen and Virulence Factors of Pertussis (Whooping Cough)

- Bordetella pertussis, a small, aerobic, non-motile, Gram-negative coccobacillus in the class Betaproteobacteria - Two adhesins are filamentous hemagglutinin and pertussis toxin - 4 toxins - Pertussis toxin: acts as an adhesin, increases infected cell production of receptor, increases mucus production

Pathogens may access the CNS several ways

- Breaks in the bones and meninges - Medical procedures (lumbar puncture) - Travel via axonal transport in peripheral neurons to the CNS - Microbes carried in the blood or lymph may penetrate the blood-brain barrier by infecting and killing cells of the meninges, causing meningitis --> Some pathogens gain access to the CNS when localized inflammation distorts the cells of the blood-brain barrier, changing its permeability

Epidemiology of Chickenpox and Shingles

- Chickenpox occurs mostly in children --> Disease is more severe in adults, usually a minor disease in children --> presumably because much of the tissue damage results from a patient's immune response, and adults have a more developed immune system than children --> can lead to fatal pneumonia in adults - Infected ~90% of children prior to vaccination - Risk of shingles increases with age, 20% of individuals infected with VZV will develop shingles --> Presumably this is because most infected individuals develop complete immunity during their bout with chickenpox - shingles usually occurs once; only about 4% of patients ever develop a second case of shingles

2 Classes of MHC Proteins

- Class I - Class II

Pathogens and Pathogenesis of viral gastroenteritis

- Common viral agents of gastroenteritis are caliciviruses, astroviruses, and rotaviruses. - Caliciviruses and astroviruses are two types of +ssRNA viruses that cause acute gastroenteritis - Both are small, naked, and star shaped and have polyhedral capsids that enter the body through the digestive tract when the person consumes contaminated food or water --> The most studied of the caliciviruses are noroviruses (they cause diarrhea) - rotaviruses are dsRNA - almost spherical and have glycoprotein spikes that act as attachment molecules and trigger endocytosis - naked, though during replication they acquire envelopes but then lose them. - Their transmission is via the fecal-oral route from contaminated food or water - ALL THREE infect cells lining the intestinal tract, where they undergo lytic replication. --> As epithelial cells die, the normal function of the intestinal tract is lost - Infections are generally self-limiting—after the virus has destroyed the epithelial layer, replacement epithelial cells grow, and function is restored.

Acne Pathogen and virulence factors (6)

- Commonly caused by Propionibacterium acnes --> G+, bacillus (rod-shaped), diphtheroid, NORMAL MICROBIOTA --> Commonly found on the skin - named for the propionic acid that is a by-product of their fermentation of carbohydrates - most commonly involved in infections of humans is Cutibacterium acnes (formerly Propionibacterium acnes), which causes acne in 85% of afflicted adolescents and young adults - Staphylococcus aureus may also cause acne

Normal Microbiota of the Skin (6)

- Compete with potential pathogens for nutrients and space - Cannot be completely removed through cleansing - typically grow in small clusters, particularly in the armpits and between the legs, where conditions are moister --> Their waste products produce body odor - May produce disease --> If they penetrate epidermis or if immune system is suppressed

Sexually Transmitted Infections (STIs) and Diseases (STDs)

- Diseases caused by STIs are called STDs - STDs are a common worldwide occurrence - Young people who experiment with sex are at risk - Presence of lesions from STDs is a risk factor for transmission of HIV - Female adolescents are at risk because the cervical lining is prone to bacterial infection --> 15 year old girl 12.5% chance of PID, 25 year old 1.25% - Prevention includes abstinence or mutual monogamy - Condoms must be used properly and consistently to provide protection, failure rate of 17-25%

Pathogenesis and Epidemiology of Traveler's Diarrhea

- E. coli diarrhea appears 24-72 hours after consumption of the bacterium - Diarrhea is mediated by enterotoxins delivered via a type III secretion system - Shiga-like toxin attaches to the surfaces of neutrophils and is spread by them throughout the body, causing widespread death of host cells and tissues. - Abnormal and massive destruction of red blood cells can clog the filtering system of the kidneys, resulting in life-threatening kidney failure --> called "hemolytic uremic syndrome"; most commonly develops in children after 2-14 days of diarrhea caused by enterohemorrhagic E. coli. - O157:H7 found in almost 50% of beef carcasses in the United States

Specificity of the B cell receptor (BCR)

- Each B lymphocyte has multiple copies of the B cell receptor on the cell membrane - Each B cell generates a single BCR - Two variable regions of the BCR form the antigen-binding sites - Each BCR recognizes only one epitope - The entire repertoire of an individual's BCRs is capable of recognizing millions of different epitopes

Traveler's Diarrhea

- Escherichia coli --> aerobic or facultatively anaerobic, Gram-negative bacilli that ferment lactose to form gas - enterotoxigenic strains (ETEC) cause diarrhea - enterohemorrhagic E. coli (EHEC)—have genes (located on transmissible plasmids) for fimbriae, adhesins, and a variety of toxins that enable EHEC to cause severe foodborne disease - O157:H7; these toxins inhibit protein synthesis, kill cells, and can cause kidney failure, resulting in death --> Shiga-like toxin binds to neutrophils and travels to other areas and causes cell death - E. coli O157:H7 also produces a type III secretion system - One set of secreted proteins disrupts a host cell's metabolism; another set becomes lodged in a cell's cytoplasmic membrane and forms receptors for the attachment of additional E. coli O157:H7 bacteria --> Such attachment apparently enables this strain of E. coli to displace normal harmless strains

Causes of Autoimmune Diseases (8)

- Estrogen may stimulate destruction of tissue by cytotoxic T cells - Some maternal cells may cross the placenta, colonize fetus, and trigger autoimmune disease later in life; more likely to survive in a daughter than son - fetal cells may also cross the placenta and trigger autoimmunity in the mother - Environmental factors such as viral infections (some develop in a few patients following their recovery from viral infections; Ex. Type I diabetes mellitus, RA) - Genetic factors such as certain MHC genes (some can promote, protect, or can trigger disease by preventing the elimination of some self-reactive T cells in the thymus) - T cells may encounter self-antigens that are normally "hidden" in sites where T cells rarely go (testes injury; T cells may enter the site of damage and mount an autoimmune response against the sperm, resulting in infertility) - Microorganisms may trigger autoimmunity because of molecular mimicry - Failure of the normal control mechanisms of the immune system (Ex. harmful, self-reactive T lymphocytes are normally destroyed via apoptosis triggered by a cell-surface receptor; however, if defects in the receptor are present, they can permit abnormal T cells to survive and cause disease.)

Pneumoccocal Pneumonia

- Fever, chills, congestion, cough, chest pain --> Results in short, rapid breathing - Blood enters the lungs, causing rust-colored sputum (neutrophils are present in this sputum) - usually lobar, affecting one or more lobes of the lungs

Tularemia Pathogen and Virulence Factors

- Francisella tularensis is a nonmotile, strictly aerobic, Gram-negative coccobacillus that is found in temperate regions of the Northern Hemisphere living in water and as an intracellular parasite of animals - Lipid capsule that discourages phagocytosis - Diverse host range (mammals, birds, fish, insects) - Endotoxin accounts for many of the signs and symptoms - Can be used as a potential biological weapon - F. tularensis can survive within infected cells by inhibiting fusion of lysosome with phagosome

HIV (5)

- Human immunodeficiency virus - causes AIDS; is not AIDS itself; HIV infection typically leads to AIDS in untreated patients - an enveloped, positive single-stranded RNA (+ssRNA) virus of the type called retroviruses --> uses reverse transcriptase to ​make a DNA copy of its genome - 2 major types

Pathogenesis and epidemiology of Schistosomiasis

- Humans are principal host for most Schistosoma species - Schistosomiasis is not found in the United States

Prevention of Type I Hypersensitivity (3)

- ID the allergens responsible and AVOID them - alter diet, filter air, dehumidifier against mold, mite-proof bedding - immunotherapy

Hypersensitivity Pneumonitis - localized Type 3

- Individuals become sensitized when minute mold spores or other antigens are inhaled deep into the lungs, stimulating the production of antibodies - reaction occurs when subsequent inhalation of the same antigen stimulates the formation of immune complexes that then activate complement - Farmer's Lung, Pigeon Breeder's Lung, Mushroom Grower's Lung, Librarian's Lung

Pathogenesis and epidemiology of Leishmaniasis (5)

- Infected macrophages stimulate inflammatory responses --> Upon initial infection, the parasites infect macrophages, which become activated but not sufficiently to kill the intracellular Leishmania --> Chemicals released by infected macrophages stimulate inflammatory responses that continue to be propagated by the infection of additional macrophages - Leishmaniasis endemic in parts of the tropics and subtropics --> Central and South America, central and southern Asia, Africa, Europe, and the Middle East

Pathogenesis of Pseudomonas Infections

- Infection can occur in burn victims; surface of a burned area provides a warm, moist environment that is quickly colonized by this ubiquitous opportunist --> Bacteria grow under the surface of the burn - The bacteria kills cells, destroys tissue, and endotoxin triggers fever, vasodilation, inflammation, shock, and other symptoms - Microbes on the burned area are not readily accessible to medical workers because the crust is generally impermeable to antimicrobial drugs, and blood vessels are absent - Debridement

Pathogenesis of Chickenpox and Shingles (6)

- Infection spreads from respiratory tract and then spreads into the liver, spleen, and lymph nodes via the blood and lymph --> After two weeks, a second wave of viruses spreads via the blood throughout the body and to the skin - Infected dermal cells cause rash characteristic of chickenpox, along with fever and malaise - viruses are shed before and during the symptoms through respiratory droplets and the fluid in lesions; dry crusts are not infective - Virus becomes latent in sensory neurons - Reactivated HHV-3 causes shingles (usually after age 45)

Pathogenesis and epidemiology of Diptheria

- Laboratory examination of the membrane or of tissue collected from the site of infection does not always reveal bacterial cells because the effects are due largely to the action of diphtheria toxin and not the cells directly - Diagnosis is based on observation of the pseudomembrane and an immunodiffusion assay, called an Elek test, in which antibodies against the toxin react with the toxin in a sample of fluid from the patient - Spread via respiratory droplets or skin contact - Vaccinated Immune individuals: asymptomatic - Vaccinated Immunocompromised: mild respiratory disease - Nonimmune individuals: severe, develop diphtheria - Mortality rate: adults- 5-10%, Children/elderly- 20%

Pathogenesis of Malaria

- Large scale erythrocyte lysis and renal failure

Review - What are the components of the lower respiratory system?

- Larynx - Trachea - Bronchi - Alveoli - Diaphragm - Various protective components --> Ciliated mucous membrane, alveolar macrophages, and secretory antibodies

Epidemiology of Legionnaires' Disease

- Legionella survives in domestic water sources --> tolerates heat and chlorination, so it can live in water pipes and other domestic water sources; in fact, legionellosis was not a common disease until modern devices provided a suitable means of transmitting the bacteria to humans: showers, vaporizers, spa whirlpools, hot tubs, air conditioning systems, and cooling towers produce aerosols containing Legionella - The elderly, smokers, and immunocompromised individuals are at increased risk for infection - Does not spread person-to-person

Pathogen of Leishmaniasis (3)

- Leishmania is a flagellated protozoan commonly hosted by wild and domestic dogs and small rodents - Infected female sand flies of the genera Phlebotomus ( and Lutzomyia transmit Leishmania from animals to humans through their bite - Of the 30 known species of Leishmania, 21 can infect humans

Rhinosinusitis

- Malaise typically accompanies the headache and inflamed nasal passages - Streptococcus pneumoniae, an alpha-hemolytic streptococcus that lacks specific Lancefield antigens (about 35% of cases) - Infective agents spread from the pharynx into the sinuses via their connections with the throat - inflammation, triggered by an infection, is responsible for the signs and symptoms of these diseases - more common in adults presumably because an adult's sinuses are developed more fully - bacteria cause fewer than 10% of cases --> It is important that physicians determine whether an infection is bacterial or viral, because overuse of antibacterial drugs, which have no effect on viruses, is partly to blame for the spread of resistance to antimicrobials among bacterial populations - treat with amoxicillin-clavulanic acid, which acts synergistically—each agent enhancing the antibacterial effect of the other

Pathogen and virulence factors of Measles (Morbillivirus) (4)

- Measles morbillivirus (-ssRNA) - single-stranded RNA virus with an enveloped helical capsid - Adhesion and fusion proteins help virus avoid immune recognition --> fusion protein triggers fusion between an infected cell and its neighbors, allowing the virus to pass from cell to cell and avoid antibodies

Pathogens, Pathogenesis, and Epidemiology of primary amebic meningoencephalopathy

- Naegleria --> ameba is a common free-living inhabitant of warm lakes, ponds, puddles, ditches, mud, and moist soil; it is also found in artificial water systems such as swimming pools, air conditioning units, humidifiers, contact lens solution, and dialysis units - enter through skin breaks, eye abrasions, inhalation of contaminated water - RARE but almost always fatal

nonprofessional antigen-presenting cells (4)

- Non-professional APCs do not typically express MHC class II molecules - may present antigens under certain conditions - Ex. microglia in the brain - Ex. stellate macrophages (Kupffer cells) in the liver

Epidemiology of viral gastroenteritis

- Noroviruses cause 90% of nonbacterial gastrointestinal infections, which is about 10% of all cases of gastroenteritis worldwide and have caused outbreaks of gastroenteritis in day care centers, schools, hospitals, nursing homes, restaurants, and, in recent years, numerous epidemics on cruise ships. --> Generally, noroviruses infect school-aged children and adults - Rotaviral gastroenteritis is more common in infants

Agglutination Tests - immune testing (2)

- Not all antigens are soluble proteins that can be precipitated by antibody - Because of their multiple antigen-binding sites, antibodies can also cross-link particles, such as whole bacteria or antigen-coated latex beads, causi​ng agglutination - can test blood type - can determine the concentration of antibodies in a clinical sample

Pathogenesis of Streptococcal Respiratory Diseases

- Occurs when normal microbiota are depleted, large inoculum is introduced, or adaptive immunity is impaired

Diagnosis, treatment, and prevention of Streptococcal Respiratory Diseases

- Often confused with viral pharyngitis - Immunological test for β hemolytic streptococci - Penicillin derivatives are an effective treatment

Genital Warts

- Papillomas (warts) on the genitalia and surrounding areas --> Large growths called condylomata acuminata may form, appear as "cauliflower" shaped - May also form on the face, trunk, hands, feet, elbows, or knees. - Caused by human papillomaviruses (HPV) (dsDNA) - HPV can cause various cancers - Common strains that cause cervical cancer - HPV 6 & 11 cause 90% of genital warts - HPV 16 & 18 cause 70% of all cervical cancer - HPVs invade skin or mucous membranes during sex - Primary concern is due to an increased risk of cervical cancer - Most common STD in the U.S. (90%) - Diagnosis made by presence of warts - Variety of methods available to remove warts - Vaccine, Gardasil, available against HPV strain associated with cervical cancer and warts --> Vaccine targets: HPV 6, 11, 16, 18

Pathogenesis of Shigellosis (professor notes)

- Pathogen colonizes cells of the small, then large intestine. Reproduces in cytosol. - Enterotoxins are proteins on Shigella that bind and cause electrolyte and water loss. Similar to cholera toxin. - Shigella can directly invade adjacent cells, thus avoiding immune detection - Shigella is rapidly destroyed in blood, bacteremia does not occur - Shiga toxin, an enterotoxin and cytotoxin, stops protein synthesis, causes cell death and dysentery

Herd Immunity (3)

- Pathogens cannot spread effectively in a population when a large proportion of individuals (typically more than 75%, but for some diseases, such as measles, more than 95%) are resistant - MUST FOLLOW RECOMMENDED IMMUNIZATION SCHEDULE TO PROTECT SOCIETY - When immunization compliance decreases, local epidemics occur

Activation of complement and inflammation - Antibody Function

- Stems of two or more IgM antibodies bind to complement protein 1 (C1), activating it to become enzymatic - begins the classical complement pathway, which releases inflammatory mediators

Dental Caries, Gingivitis, and Periodontal Disease Pathogen and virulence factors

- Streptococcus mutans is a frequent cause of caries - G+ coccus - Dextran and pili allow biofilm formation on the tooth --> insoluble, sticky, polysaccharide slime (dextran) - Porphyromonas gingivalis causes periodontal disease - Anaerobic G- bacillus - Proteases break down gingival tissue

African Viral Hemorrhagic Fevers Signs and Symptoms

- Sudden fever, intense fatigue, muscle pain, headache, and sore throat - Progresses to vomiting, diarrhea, and rash - Minor petechiae progress to severe internal hemorrhaging - Death results from shock, seizures, or kidney failure

Staphylococcal Toxic Shock Syndrome

- Sudden-onset fever, chills, vomiting, diarrhea, low blood pressure, confusion, and severe red rash - Individuals go into shock if untreated - Caused by some strains of S. aureus - S. aureus grows exceedingly well on super-absorbent tampons, especially when a blood-soaked tampon remained in place for a prolonged period - These strains produce exotoxins called toxic shock syndrome toxins (TSST), a superantigen --> exotoxins bind simultaneously to major histocompatibility complex II molecules on antigen-presenting cells and T cell receptors on T cells; however, they bind to sites other than the normal antigen-binding sites of these immune system molecules. --> When a toxin molecule binds two defensive cells together in this fashion, it activates the T cell --> As a result of the action of many such toxin molecules, many more T cells are activated than in a cellular immune response. --> These activated T cells release an overabundance of cytokines that trigger the manifestations of TSS - 75% of cases are due to TSST-1 - Absorption of toxin into blood triggers toxic shock syndrome. Causes low blood pressure, coma, and death. - Most cases occur in menstruating females - Diagnosis based on signs and symptoms - Considered medical emergency - Requires removal of foreign material and antimicrobial drugs - Avoiding tampons or using less absorbent tampons reduces risk

Movement of Blood and Lymph - Prof Notes

- The right ventricle pumps blood to the lungs --> Oxygen enters blood, and carbon dioxide diffuses out - Oxygenated blood returns to the heart through the left ventricle - Blood then moves to the arteries and capillaries --> Capillaries carry blood to the surrounding tissues --> Leaked fluid is picked up by the lymphatic vessels

Microbiome of the Esophagus, Stomach, Duodenum

- These regions are almost free of microbes - Peristalsis and rapid transport of food helps prevent microbial colonization

Why are there may classes of antibodies? (2)

- Threats confronting the body can be extremely variable - The class involved in any given antibody immune response depends on the type of invading foreign antigens, the portal of entry involved, and the antibody function required.

synapses

- Tiny spaces between neurons; the gaps between neurons are referred to as synaptic gaps. - at the terminal ends of axons - mediates transfer of a signal to a neighboring postsynaptic cell

TLRs - Nonspecific Chemical Defenses Against Pathogens

- Toll-like receptors (TLRs) --> Integral membrane proteins produced by phagocytic cells - RECOGNIZE PAMPs --> Bind PAMPs --> Initiate defensive responses ----> Secretion of inflammatory mediators or interferons ----> Stimulate adaptive immune response ----> Apoptosis

Pathogens and Virulence Factors of bacterial intoxications (toxifications) (food poisoning)

- Toxins of Staphylococcus aureus, which is a normal member of the microbiome of the skin and upper respiratory system, cause staphylococcal food poisoning --> common --> processed meats, custard pastries, potato salad, and ice cream - five enterotoxins --> These proteins (designated A through E) stimulate intestinal muscle contractions, trigger nausea, and cause intense vomiting --> heat stable, remaining functional at 100°C for up to 30 minutes, which means they are not usually inactivated by warming or reheating food

Pathogen and virulence factors of Toxoplasmosis

- Toxoplasma gondii - an apicomplexan protozoan that lives in the nucleated cells of wild and domestic mammals and birds - Cats are the primary host

Epidemiology of Hansen's

- Transmitted by person-to-person contact or breaks in the skin - Individuals are typically infected only after years of intimate social contact with a victim - Given that the nasal secretions of patients with lepromatous leprosy are loaded with mycobacteria, infection presumably occurs via inhalation of respiratory droplets

Pathogens of Endocarditis

- Viridans streptococci cause almost half the cases --> α-hemolytic, G+ streptococci - Other opportunistic bacteria: - Staphylococcus epidermidis, S. aureus, S. pneumoniae, Enterococcus, Escherichia, Neisseria, Pseudomonas, Bartonella, Mycobacterium, Mycoplasma

M Protein (2)

- a cytoplasmic membrane component that destabilizes complement and interferes with phagocytosis and lysis of the bacterium - virulence factor of Streptococcus pyogenes (group A Streptococcus)

Epidemiology of Dermatophytoses (3)

- among the few contagious fungi - Spores and bits of hyphae, along with dead skin cells and hair, are constantly shed from infected individuals, making recurrent infections common - Dermatophytes infecting humans are classified according to their natural habitats (anthropophilic, zoophilic, geophilic)

Eosinophilia (3)

- an abnormally high number of eosinophils in the blood - often indicative of helminth infestation - also common in patients w/ allergies

Immunodiffusion (2)

- an immune test in which antibodies and antigens diffuse from separate wells in agar to form a line of precipitate - Determines optimal antibody and antigen concentrations

common cause of acute anaphylaxis (4)

- an insect's venom in an allergic and sensitized individual --> The first sting produces sensitization and the formation of IgE antibodies --> successive stings (which may occur years later) produce the anaphylactic reaction - certain foods (peanuts), vaccines containing egg proteins, some antibiotics such as penicillin, iodine dyes, local anesthetics, latex, and certain narcotics such as morphine

synaptic cleft

- an intercellular space about 40 nm wide between the axon terminal and the postsynaptic cell - stops the transmission of electrical signals

Clostridium (6)

- anaerobic, Gram-positive, endospore-forming bacillus that is ubiquitous in soil, water, sewage, and the gastrointestinal tracts of animals and humans - grows in the vaginas of 1-9% of healthy women - Pathogenicity is due in great part to the ability of endospores to survive harsh conditions and to the vegetative cells' secretion of 11 toxins that lyse erythrocytes and leukocytes, increase vascular permeability, reduce blood pressure, and kill cells, resulting in irreversible damage - does not affect healthy tissues and is not invasive --> A traumatic event, such as a surgical incision, puncture wound, gunshot wound, crushing trauma, abortion, or compound fracture, must introduce endospores into dead tissue --> n the anaerobic environment of dead tissue, they germinate and grow on nutrients released by the dead cells

adaptation of Immunochromatographic assays (4)

- antibodies are coated on membrane strips, which serve as dipsticks - At one end, anti-antibodies are fixed in a line so that they cannot move in the membrane - lower portion of the membrane is coated with antibodies against the antigen in question - These antibodies are linked to a color indicator in the form of a colloidal metal and are free to move up the membrane by capillary action until their progress is arrested by the line of anti-antibodies

Basophils (2)

- capable of diapedesis but NOT phagocytic - instead, they release inflammatory chemicals

Medulla of Lymph Node (3)

- central region - filters lymph - houses lymphocytes

Bubonic Plague

- characterized by buboes --> The sudden appearance of smooth, enlarged, reddened, and painfully inflamed lymph nodes --> commonly occur in the groin, armpits, or neck near the site of infection - fever, chills, malaise, muscular pain, severe headache, bacteremia, and septicemia --> latter conditions result in increased heart rate, lowered blood pressure, disseminated intravascular coagulation, subcutaneous hemorrhaging, and death of tissues, which turn black as a result of secondary infection of gangrenous bacteria - Because of the extensive darkening of dead skin, plague has been called "Black Death." - fatal if untreated in 50% of patients

Adjuvants (4)

- chemical added to a vaccine to increase it ability to stimulate active immunity - increase the effective antigenicity of the vaccine by stimulating immune cell receptors and their actions - Ex. alum, lipid A, double-stranded RNA - may stimulate local inflammation

Tissue Repair (4)

- delivery of extra nutrients and oxygen to the site of dilated BVs - if tissue contains undifferentiated stem cells, tissue can be fully restored - if fibroblasts are largely involved, scar tissue forms and inhibits normal function - cardiac and brain tissue don't replicate and can't be repaired

Chronic Inflammation (2)

- develops slow, long-lasting - can result in tissue death, causing disease

Hemolytic disease of the newborn (7)

- disease that results when antibodies made by an Rh- woman cross the placenta and destroy the RBCs of an Rh+ fetus - first exposure creates antibodies against Rh+ in the MOTHER - during the second exposure (second Rh+ fetus), the Rh+ anitbodies cross the placenta from the mother and destroy the Rh+ RBCs of the second fetus - RhoGAM administered to prevent hemolytic disease of the newborn DURING FIRST PREGNANCY; once antibodies are created it's not effective --> admin. 28 weeks into their pregnancy and also within 72 hours following abortion, miscarriage, or childbirth - Initially, only IgM antibodies are produced, and because IgM is a very large molecule that cannot cross the placenta, no problems arise during this first pregnancy - IgG antibodies can cross the placenta, so if during a subsequent pregnancy the fetus is Rh+, anti-Rh IgG molecules produced by the mother cross the placenta and destroy the fetus's Rh+ red blood cells.

Systemic Diseases

- diseases that affect the whole body rather than a local area - blood and lymph can carry pathogens throughout the body to cause them

Treatment of East African trypanosomiasis

- early bloodborne stages treated with with suramin - later, brain-affecting, stages with fexinidazole --> replacing a toxic arsenic-based drug—melarsoprol—that has been used historically

Pneumonic Plague

- fatal if untreated in nearly 100% of cases - occurs when plague bacilli in a patient with bubonic plague spread from the bloodstream to the lungs or are inhaled - develops rapidly - Fever, malaise, severe cough, bloody and frothy sputum, and difficulty in breathing can arise within a few hours of infection

Pathogenesis of Arboviruses

- female Aedes or Culex mosquitoes carry the viruses among infected hosts - Mosquitoes remain infected with arboviruses, which they pass to their offspring in eggs; mothers and their female young are a continual source of new infections - Viruses overwinter in eggs or hibernating mosquitoes - Arboviruses enter target cells via endocytosis and replicate within them. They produce viremia and can cross the blood-brain barrier by an unknown mechanism to cause encephalitis - In horses and humans, viruses are released from infected cells into the blood (viremia), but the concentration of viruses in their blood is never high enough to infect mosquitoes, so horses and humans are "dead-end" hosts - Most patients experience severe flulike symptoms but survive, though 50% of patients still suffer a year later with headaches, cognitive and memory impairment, fatigue, tremors, or depression.

Signs and Symptoms of Chickenpox and Shingles (3)

- fever - characteristic rash on back and trunk that spreads to face and extremeties - in 15-10% of cases, the virus reactivates years later, causing a painful shingles rash on a band of skin innervated by an infected nerve

Poxviruses characterized by: (5)

- fever (as high as 42 C or 107 F) - malaise - delerium - prostration - infection of the eye may induce blindness

People with staphylococcal lesions should refrain from working with: (5)

- food - patients with open wounds - immunocompromised patients - women in labor - nurseries or operating rooms

bacterial intoxications (toxifications) (food poisoning)

- food poisonings caused by toxins—the microbe itself is either not present or not the immediate problem

Class I MHC Protein

- found on the cytoplasmic membranes of all human cells except red blood cells - found on all nucleated cells - nonspecific; can bind thousands of different epitiopes (unlike enzymes)

Mycoses

- fungal diseases - Spread from the lungs to the CNS via the blood - Mushroom toxins can produce hallucinations and neurological problems - May also produce fungal meningitis - coccidioidomycosis, histoplasmosis, and blastomycosis

Subcutaneous Mycoses (2)

- fungal infections in the hypodermis and muscles - wound mycoses

Allografts (4)

- grafts transplanted between genetically distinct members of the same species - Most grafts performed in humans - Because the MHC proteins of the allograft are different from those of the recipient, allografts typically induce a strong type IV hypersensitivity, resulting in graft rejection - Rejection must be stopped with immunosuppressive drugs if the graft is to survive

Xenografts (3)

- grafts transplanted between individuals of different species - usually very different from the tissues of the recipient, both biochemically and immunologically, they usually provoke a rapid, intense rejection that is very difficult to suppress - xenografts from mature animals are not commonly used therapeutically

The Lacrimal Apparatus (5)

- group of structures that produce and drain away tears - tears either evaporate or drain into small lacrimal canals, which carry them into nasolacrimal ducts that empty into the nose --> tears join the nasal mucus and flow into the pharynx, where they are swallowed - Blinking spreads tears and washes surface of the eye - Lysozyme in tears destroys bacteria

point-of-care testing

- health care providers do not have to send specimens to a laboratory for testing but can perform the test at the patient's bedside or in a doctor's office

Infant Botulism

- infants usually under 6 months - differs from foodborne botulism in that the toxin is not ingested - the bacterium actually grows in a child's intestinal tract, where it secretes toxin - characterized by nonspecific symptoms: crying, constipation, and "failure to thrive." - Infants are susceptible to colonization because their GI tracts do not have a sufficient number of benign microbiota to compete with C. botulinum for nutrients and space - adults prevent growth of the bacterium due to microbial antagonism

Why is HIV itself difficult to locate in a patient? (2)

- it becomes a provirus inserted into chromosomes - for years it can be kept in check by the immune system

What happens when any nucleated cell synthesizes proteins? (3)

- it displays epitopes from them in the antigen-binding grooves of MHC class I molecules on its cytoplasmic membrane - Thus, when viruses are replicated inside cells, epitopes of viral proteins are displayed on the host cell's surface - active Tc cell binds to an infected cell via its TCR, which is complementary to the MHC I protein-epitope complex, and via its CD8 glycoprotein, which is complementary to the MHC class I protein of the infected cell

What must be done when microbes are killed for use in vaccines? (3)

- it is important that their antigens remain as similar to those of living organisms as possible - chemicals used must not alter the antigens responsible for stimulating protective immunity --> final amount of chemicals is so small, it doesn't pose health risks

There is no normal microbiota of the cardiovascular system. Why?

- it's a closed system- there is no easy portal of entry

Mast Cell (6)

- large, round, specialized​ relatives of white blood cells --> derived from other stem cells in the bone marrow - in connective tissues other than blood --> found in sites close to body surfaces, including the skin and the walls of the intestines and airways - cytoplasm packed with large granules that are loaded with a mixture of potent inflammatory chemicals (HISTAMINE, KININS, PROTEASES) - the binding of allergens to IgE on mast cells activates other enzymes that trigger the production of ​leukotrienes​ and prostaglandins, lipid molecules that are powerful inflammatory agents

Size of Antigens

- larger molecules with molecular masses between 5000 and 100,000 daltons are better antigens - smaller molecules (>5000 daltons) evade detection, making for poor antigens - can bind to carrier molecules (often proteins) and become antigenic and stronger - Ex. penicillin is small but can bind and become antigenic

Basophils (3)

- least numerous type of leukocyte in blood - filled with inflammatory chemicals similar to those found in mast cells - Sensitized basophils bind IgE and degranulate in the same way as mast cells

Antigen-binding groove (4)

- lies between two polypeptides that make up an MHC - antigens bind here - inherited variations in AA sequences modify the shape of this groove --> determine which epitopes can be bound and presented

Mucous Membranes (4)

- line all body cavities open to environment - 2 distinct layers: epithelium and deep connective tissue that supports the epithelium - NONSPECIFIC - limit infection both physically and chemically

Plasma (4)

- liquid portion of blood - most water - contains electrolytes (ions), dissolved gases, nutrients, and a variety of proteins - Includes iron-binding compounds, complement proteins, and antibodies

Diagnosis of Staphylococcal Scalded Skin Syndrome (SSSS) (2)

- made on the basis of the distinctive sloughing of the skin - fluid in the blisters of SSSS does not contain S. aureus, since the disease is mediated by toxins released from a site of infection that may be elsewhere in the body

sclera

- makes up fibrous tunic - a direct extension of the dura mater of the brain

Viral Hemagglutination Inhibition Test (4)

- many viruses (including influenzaviruses) have surface proteins that naturally clump red blood cells - Antibodies against influenzavirus inhibit viral hemagglutination --> if serum from an individual stops viral hemagglutination, we know that the individual's serum contains antibodies to that particular strain of influenzavirus - can be used to detect antibodies against influenza, measles, mumps, and other viruses that naturally agglutinate red blood cells, thus revealing that a patient has been infected or immunized with the virus in question

Antigens (2)

- molecules the body recognizes as foreign and worthy of attack - Lymphocytes bind to antigens and can then trigger adaptive immune responses

Rabies

- neuromuscular disease characterized by hydrophobia, seizures, hallucinations, and paralysis - fatal if untreated - initial signs/symptoms: pain or itching at the site of infection, fever, headache, malaise, and anorexia - signs once the virus reaches the CNS: hyperaggressive and excitable behavior, hydrophobia (triggered by the pain involved in attempts to swallow water), seizures, disorientation, hallucinations, and paralysis - Death results from respiratory paralysis and other neurological complications

The entire nervous system is composed of two basic types of cells:

- neurons --> cytoplasmic membrane of a neuron generates an electrical signal called an action potential or nerve impulse - supportive cells called neuroglia --> provide a supportive scaffolding, insulation, and nutritive support and phagocytize microbes

Bacterial Vaginosis

- noninflammatory infection of the vagina --> "vaginosis" rather than "vaginitis" - homogenous white vaginal discharge with a "fishy" odor - some itching/irritation at vaginal opening - esults when the normal lactobacilli of the vagina are replaced with a large number of facultatively or obligate anaerobic bacteria such as Gram-positive Gardnerella vaginalis and Mycoplasma hominis - a decline in the number of lactobacilli populating the vagina results in a pH in the vagina higher than the normal 4.5 --> This either promotes or allows the growth of the bacteria associated with bacterial vaginosis - associated with having multiple sexual partners and vaginal douching - diagnose bacterial vaginosis by its signs, including odor, discharge characteristics, and vaginal pH greater than 4.5 - The presence of so-called clue cells, which are vaginal epithelial cells completely covered with bacteria, supports the diagnosis - treatment with oral or vaginal metronidazole or clindamycin - no absolute preventive measures, but sexual abstinence and refraining from douching are beneficial

tuberculoid leprosy

- nonprogressive form of the disease --> Patients with a strong T cell immune response (cell mediated) are able to kill cells infected with the bacterium - Regions of the skin that have lost sensation as a result of nerve damage are characteristic

Pathogenesis of Viral Meningitis

- often spread from person to person via fecal contamination of food, water, or hands - Though ingested enteroviruses attack cells lining the intestinal tract, they do not cause gastrointestinal illnesses; instead, enteroviruses spread via the bloodstream (viremia) to infect other organs, including the meninges. - primarily attack cells lining the intestinal tract and lungs, in the latter case producing colds - The viruses are cytolytic—they kill their target cells --> Damage to cells in the meninges triggers meningitis - incubation period of enterovirus infections is between three and seven days, and patients recover completely without treatment after another seven to ten days

membrane attack complex (MAC) (4)

- one end product of a full cascade - forms a circular hole in a pathogen's membrane - production of numerous MACs leads to lysis of the pathogen - bacterium causing gonorrhea is particularly sensitive to MACs

HIV-1

- prevalent in the United States and Europe

Cryptosporidiosis

- protozoan disease - Severe watery diarrhea (~ 2 weeks) with potentially serious complications - Headache, muscular pain, cramping, nausea, fatigue, and severe fluid and weight loss accompany the diarrhea - Life-threatening malabsorption, hepatitis, and pancreatitis can complicate the disease. - Ampicomplexan Cryptosporidium parvum --> banana-shaped, gliding sporozoite that has an apical complex of organelles specialized for penetrating host cells; thus, it is an apicomplexan --> Sporozoites form thick-shelled oocysts, which are the infective stage, inside cells --> With a complex series of cell divisions and stages, oocysts eventually develop four internal sporozoites, which escape to continue the life cycle - Pathogenicity of C. parvum unclear, but suspected that death of infected cells causes electrolyte and water loss. - Infection results from drinking contaminated water - Treated with fluid and electrolyte replacement - Prevented with proper hygiene - may be fatal in HIV patients

hemolysis (5)

- recipient has preexisting antibodies to foreign antigens, then the donated blood cells will be destroyed immediately - the antibodies will agglutinate the cells and complement will rupture them - releases hemoglobin into the bloodstream, which may cause severe kidney damage - membranes of the ruptured blood cells trigger blood clotting within blood vessels, blocking them and causing circulatory failure, fever, difficulty in breathing, coughing, nausea, vomiting, and diarrhea - If the patient survives, recovery follows the elimination of all the foreign red blood cells

Signs/Symptoms of Inflammation (4)

- redness in light skin (rubor) - localized heat (calor) - edema (swelling) - pain (dolor)

Zika Virus

- relatively mild fever, rash, conjunctivitis, headache, and muscle or joint pain for several days to a week - most patients are asymptomatic - congenital Zika syndrome: brain abnormalities, including problems with sight, hearing, limb movements, and learning; possible microcephaly --> may also adversely affect normal development of the heart, digestive system, or genitalia

characteristic symptoms of type I hypersensitivity reactions LOCAL (5)

- respiratory distress - rhinitis (inflammation of the nasal mucous membranes, commonly called "runny nose") - watery eyes - inflammation - reddening of the skin

Nonparalytic Polio - polio conditions

- results from polioviruses invading the meninges and central nervous system - muscle spasms and back pain in addition to the general symptoms of minor polio - 2% of all cases

two systemic conditions resulting from immune complex-mediated hypersensitivity

- rheumatoid arthritis - systemic lupus erythematosus

MALT (6)

- secondary lymph organ - contains most of the body's lymphocytes - lack tough outer capsule - lymphoid tissue associated with the mucous membranes of the appendix - lymphoid tissue of the respiratory tract, vagina, urinary bladder, and mammary glands - discrete bits of lymphoid tissue called Peyer's patches in the wall of the small intestine

Tonsils (4)

- secondary lymph organ - lack tough outer capsule - similar to lymph nodes but have no afferent/efferent vessels - sample microbes that enter the mouth or nose

Sebaceous (Oil) Glands (3)

- secrete sebum --> Helps keep skin pliable and less likely to break or tear --> Contains fatty acids that lowers skin to about pH 5, which is inhibitory to many bacteria

Titration (3)

- serial dilution of blood serum to test for agglutination activity - rising levels may indicate the presence of active infectious disease - falling levels may indicate the successful conclusion of a fight against an infection

Hyaluronic Acid Capsule of Streptococcus pyogenes (group A Streptococcus) (2)

- serves to "camouflage" the bacterium - hides it from phagocytes since hyaluronic acid is a natural chemical in the body

subacute sclerosing panencephalitis (SSPE)

- slow, progressive disease of the central nervous system - involves personality changes, loss of memory, muscle spasms, blindness, and death - begins one to ten years after the initial infection with measles virus --> lasts a few years before killing the patient - A defective measles virus that cannot make a capsid causes SSPE - The defective virus replicates and moves from brain cell to brain cell via cell fusion, limiting the functioning of infected cells and resulting in the symptoms - afflicts fewer than 7 measles patients in 1 million and is becoming rare as a result of childhood immunizations

Cytomegalovirus (CMV)

- so named because cells infected with this virus become enlarged - herpesvirus - may result from initial infections or from latent viruses - Most people infected with CMV are asymptomatic, but fetuses, newborns, and immunodeficient patients are susceptible to severe complications of CMV infection - 10% of congenitally infected newborns develop signs of infection, including enlarged liver and spleen, jaundice, and anemia - may be teratogenic (can cause birth defects) when the virus infects stem cells in an embryo or fetus --> In the worst cases, mental retardation, hearing and visual damage, or death may result - AIDS patients and other immunosuppressed adults, such as transplant recipients, may develop pneumonia, blindness (if the virus targets the retina), or cytomegalovirus mononucleosis, which has signs and symptoms similar to those of infectious mononucleosis caused by Epstein-Barr virus

Geophilic dermatophytes (2)

- soil fungi - transmitted to humans via direct exposure to soil or to dusty animals

What is another way that some bacteria can get iron? (4)

- some can secrete the protein hemolysin --> punches holes in the cytoplasmic membranes of red blood cells, releasing iron-containing hemoglobin --> bacterial proteins then bind hemoglobin to the bacterial membrane and strip it of its iron - Ex. Neisseria meningitidis, a pathogen that causes often fatal meningitis, produces receptors for transferrin and plucks iron from the bloodstream as it flows by.

5 Distinct Attributes of Adaptive Immunity

- specificity - inducibility - clonality - unresponsiveness to self - memory

Diagnosis, Prevention, and Treatment of C. diff. (Antimicrobial-Associated) Diarrhea

- test stool for Toxins A & B or use xTAG GPP to find C. difficile in the stool - colonoscopy can reveal the yellowish lesions of the pseudomembranes - prevention involves avoid unnecessary use, especially prolonged use, of antimicrobial drugs - endospores of Clostridium are resistant to most disinfectants; therefore, handwashing and wearing gloves are the cornerstones of prevention - Generally, cessation of the causative antimicrobial may be all that is necessary to restore the normal microbiome - Treatment for moderately severe cases entails the use of oral metronidazole or vancomycin - Antidiarrheal drugs should be avoided, because diarrhea is actually beneficial in that it dilutes and eliminates bacterial cells and their toxins - Physicians have successfully treated patients who have had recurrent C. diff. diarrhea with "fecal transplants." --> reestablishes the normal microbiome

Diagnosis of Type I Hypersensitivity (6)

- test variously called ImmunoCAP Specific IgE blood test, CAP RAST, or Pharmacia CAP --> suspected allergens are mixed with samples of the patient's blood --> basically the test detects the amount of IgE directed against each allergen --> High levels of a specific IgE indicate a hypersensitivity against that allergen - injecting into the skin a very small quantity of a dilute solution of the allergens being tested --> skin test on forearm/back can check for dozen+ allergens simultaneously

Fibrinogen (4)

- the blood's clotting protein - delivered to infection site thanks to vasodilation and increased permeability - prevents the spread of pathogens and toxins from the area - pus forms in the walled off area (abscess) (pimples, boils, pustules)

glomerulonephritis

- the body does not remove from circulation antibodies bound to the antigens of some strains of group A Streptococcus (GAS) - antibody-antigen complexes accumulate in the glomeruli of the kidneys, triggering inflammation of the glomeruli and nephrons - obstructs blood flow through the kidneys and leads to hypertension (high blood pressure) and low urine output. - The patient's urine often contains blood and proteins. - Young patients usually recover fully from glomerulonephritis, but progressive and irreversible kidney damage may occur in adults

Opsonization (3)

- the coating of pathogens by proteins called Opsonins, making them more vulnerable to phagocytes - Opsonins increase the number and kinds of binding sites on a microbe's surface - complement proteins or antibodies help prepare pathogens for easier phagocytizing

Innate Immunity (4)

- the first 2 lines of defense - "natural" or "native" immunity; present at birth - always active, NONspecific, rapid - works against a wide variety of pathogens, including parasitic worms, protozoa, fungi, bacteria, and viruses

Pathogenesis of Respiratory syncytial virus (RSV) infection

- the virus causes syncytia to form in the lungs --> a giant, multinucleated cell formed from the fusion of virally infected cells to neighboring cells - Plugs of mucus, fibrin, and dead cells in the bronchioles make it difficult to breathe - action of cytotoxic T cells and other specific immune responses to RSV infection further damages the lungs.

How are the cytokines named? (3)

- their cells of origin - their function - and/or the order in which they were discovered

Pathogenesis of Staphylococcus for Folliculitis (7)

- transmitted via direct contact or by fomites (inanimate carriers of infective agents; ex. contaminated clothing, bedsheets, and medical instruments) - Staphylococcus on the skin grows into hair follicles and invades sebaceous glands --> triggers fever and inflammation --> causes the follicle to enlarge and fill with pus composed of leukocytes, dead cells, and bacteria - infection may spread into the hypodermis to form a furuncle or into neighboring hair follicles to form a carbuncle - Infection can spread into the blood (bacteremia) and move to organs beyond the skin (S. aureus and infrequently S. epidermidis) --> infection in the lining of the heart, lungs, and bones, causing endocarditis, pneumonia, and osteomyelitis, respectively

Treatment of Folliculitis

- treat staphylococcal skin infections with topical mupirocin --> it is critical to clean and drain abscesses of pus for topical therapy to be effective - Dicloxacillin (semisynthetic, oral penicillin not inactivated by β-lactamase) is the drug of choice - Vancomycin used to treat resistant strains --> (Strains resistant to many common antimicrobial drugs, including natural penicillin, methicillin, macrolides, aminoglycosides, and cephalosporin) --> vancomycin-resistant strains of S. aureus (VRSA) are increasing

Treatment and Prevention of Cellulitis (3)

- treat with cephalexin - Good general hygiene and cleanliness - Abrasions and other breaks in the skin of children should be thoroughly cleansed with soap and water, particularly if there has been contact with impetigo patients or contaminated fomites

Treatment of Staphylococcal Scalded Skin Syndrome (SSSS) (2)

- treatment involves intravenous drugs such as semisynthetic nafcillin or oxacillin that do not allow β-lactamase to bind --> because many strains of Staphylococcal aureus produce b-lactamase, which deactivates many drugs in the penicillin class

What are scientists trying to do with TLRs? (2)

- trying to stimulate TLRs so as to enhance a body's immune response to pathogens and immunizations - methods to inhibit TLRs may provide us with ways to counter inflammatory disorders and hyperimmune responses

Mycetomas - wound mycoses (12)

- tumorlike infections of the skin, fascia (lining of muscles), and bones of the hands or feet caused by soil fungi of several genera in the division Ascomycota: Madurella, Pseudallescheria, Exophiala, and Acremonium - These fungi are distributed worldwide, but infection is most prevalent in countries near the equator - Prick wounds and scrapes caused by twigs, thorns, or leaves introduce these fungi into humans - people who work barefoot in soil are most at risk - Infection begins near the site of a wound with the formation of small, hard, subsurface nodules that slowly worsen and spread as time passes - Local swelling occurs, and ulcerated lesions produce pus - Infected areas release an oily fluid containing fungal spores and hyphae - the fungi spread to more tissues, destroying bone and causing permanent deformity - A combination of the symptoms and microscopic demonstration of fungi in samples from the infected area is diagnostic for mycetomas - Treatment involves surgical removal of the mycetoma that may, in severe cases, involve amputation of an entire limb - one to three years of antifungal therapy with ketoconazole - treatment does not always cure

Agranulocytes (3)

- type of leukocyte having a uniform cytoplasm lacking large granules - granules ARE visible with an electron microscope - 2 types (monocyte, lymphocyte)

Epidemiology of Botulism

- ~60 cases of foodborne and wound botulism per year in U.S. - Infant botulism most common form in U.S.; 100 cases annually - cases result from inhalation of endospores in dust or ingestion in food; unpasteurized ("natural") honey is involved in about a third of cases of infant botulism

Life cycle of Anisakis.

1. Marine mammals excrete eggs 2. Two larval stages develop inside eggs 3. eggs hatch and larvae swim freely 4. krill eat larvae 5. fish eat krill 6. fish eat fish 7a. Marine mammals eat infected fish. Larvae mature, mate, and lay eggs in intestine. 7b. Humans eat infected, raw, or undercooked fish and become accidental hosts

The life cycle of Trypanosoma brucei - African Sleeping Sickness

1. Noninfective Trypanosoma matures into an infective form within salivary gland of tsetse fly 2. Tsetse fly injects trypanosomes while feeding 3. Trypanosomes are carried via blood and lymph to other sites 4. Trypanosoma replicates by binary fission in bodily fluids, including blood, lymph, and spinal fluid. Thinner progeny remain infective in the body; shorter, thicker ones are infective to tsetse flies 5a. Some trypanosomes invade CNS 5b. Tsetse flies ingest thicker trypanosomes during blood meal 6. Trypanosomes reproduce by binary fission, becoming non-infective forms in midgut of tsetse fly. Noninfective forms migrate to salivary glands.

Place the following steps of phagocytosis in the order that they occur: 1) Endosome fuses with lysozome 2) Dendritic cell engulfs Rhinovirus 3) Epitopes are attached to MHC-II 4) Digestion of the Rhinovirus 5) MHC-II plus the attached epitope move to the outside of the dendritic cell

2,1,4,3,5 2) Dendritic cell engulfs Rhinovirus 1) Endosome fuses with lysozome 4) Digestion of the Rhinovirus 3) Epitopes are attached to MHC-II 5) MHC-II plus the attached epitope move to the outside of the dendritic cell

Review - What are the differences between hypersensitivity pneumonitis, rheumatoid arthritis, glomerulonephritis, and systemic lupus erythematosus? A. Hypersensitivity pneumonitis is caused by foreign antigens, while rheumatoid arthritis and systemic lupus erythematosus are caused by autoantigens and glomerulonephritis can be caused by either foreign or autoantigens. B. Hypersensitivity pneumonitis involves antibody production against DNA in the lungs, while rheumatoid arthritis, glomerulonephritis, and systemic lupus erythematosus involve antibody formation against proteins. C. Hypersensitivity pneumonitis and glomerulonephritis are worse upon sunlight exposure. D. Hypersensitivity pneumonitis, glomerulonephritis, and systemic lupus erythematosus involve the formation of IgM-IgG complexes, while rheumatoid arthritis involves antigen-antibody complexes.

A. - Rheumatoid arthritis and systemic lupus erythematosus are autoimmune diseases caused by a type III hypersensitivity to autoantigens, while hypersensitivity pneumonitis is caused by long-term exposure to inhaled antigens. Glomerulonephritis can be caused by either autoantigens or foreign antigens

Which of the following statements concerning rheumatoid arthritis (RA) is TRUE? - Accumulations of antibody complexes lead to inflammation in and destruction of the joints. - The symptoms are due to damage caused by cytotoxic T cells. - There is no genetic influence on the likelihood of developing RA. - The onset of disease is clearly correlated with having been infected with a specific microbe. - It occurs in humans and animals.

Accumulations of antibody complexes lead to inflammation in and destruction of the joints

Cyclosporine - Immunosuppressive Drugs (7)

Action: Blocks T cell responses - a polypeptide derived from fungi - prevent production of interleukins and interferons by T cells, thereby blocking Th1 responses - acts only on activated T cells and has no effect on resting T cells --> far less toxic than the nonspecific drugs previously described - When it is given to prevent allograft rejection, only activated T cells attacking the graft are suppressed - Because steroids have a similar effect, the combination of glucocorticoids and cyclosporine is especially potent and can enhance survival of allografts

Which of the following is NOT a step that ultimately leads to antibody production? - Immature B cells conducting surveillance for foreign epitopes - Differentiation of plasma cells - Activation of helper T cells by dendritic cells - Activation of cytotoxic T cells by helper T cells

Activation of cytotoxic T cells by helper T cells - The activation of cytotoxic T cells leads down the path of cell-mediated immunity.

Tinea unguium; onychomycosis

Agents: - T. rubrum; T. mentagrophytes var. interdigitale Common Signs: - Superficial white onychomycosis: patches or pits on the nail surface. - Invasive onychomycosis: yellowing and thickening of the distal nail plate, often leading to loss of the nail Source: - Humans

Tinea capitis

Agents: - Tinea capitisM. canis; M. gypseum; T. equinum; T. verrucosum; T. tonsurans; T. violaceum; T. schoenleinii Common Signs: - Ectothrix invasion: fungus develops arthroconidia on the outside of the hair shafts, destroying the cuticle - Endothrix invasion: fungus develops arthroconidia inside the hair shaft without destruction - Favus: crusts form on the scalp, with associated hair loss Source: - Humans; can be acquired following contact with contaminated soil or animals

Epidemiology of Coccidioidomycosis

Any activity that disrupts the soil can disseminate arthroconidia into the air.

Which pair of molecules do NOT directly interact with one another? - CD4 and MHC-II - BCR and TCR - CD8 and MHC-I - BCR and epitope

BCR and TCR - Both of these molecules interact with epitopes. BCRs interact with epitopes on the whole pathogen. TRCs interact with processed epitopes when presented on MHC-II.

Review - Which disease can have an incubation period as long as 60 years? A. Cryptococcal meningitis. B. Primary amebic meningoencephalopathy. C. Prion disease. D. African sleeping sickness.

C

How does the replication of HIV differ from the replication of bacteriophage T4?​​

Bacteriophage T4 is a DNA virus; therefore, it does not have reverse transcription. Further, T4 does not integrate into a bacterium's chromosome; it assembles completely before being released from the cell; it has no envelope; and it does not carry enzymes.​

Review - Which disease does the acidophile Helicobacter pylori cause? A. Acute necrotizing ulcerative gingivitis. B. Periodontal disease. C. Peptic ulcers D. Osteomyelitis.

C

Why are inactivated vaccines safer than live vaccines?

Because neither whole agent nor subunit vaccines can replicate, revert, mutate, or retain residual virulence

The skin and the mucous membranes are similar in which of the following aspects? - Both have multiple layers of epidermal cells. - Both have an outer layer of dead cells. - Both have epithelial cells packed closely together. - Both produce mucus.

Both have epithelial cells packed closely together. - The epidermal cells in the skin may be arranged in several layers, while the epidermis in some mucous membranes is only one-cell thick, but in both cases the cells are tightly packed.

Review - What disease is caused by Gardnerella vaginalis? A. Urethritis. B. Toxic shock syndrome. C. Vaginosis. D. Vaginal yeast infections.

C

4 Chemicals that can trigger/promote blood vessel dilation

Bradykinin - powerful vasodilator peptide - forms when blood clotting follows damage to a BV --> triggers a plasma protein to convert into a peptide - cause VD of arterioles Prostaglandin - released by patrolling macrophages - use TLRs and NOD proteinsn to ID invaders Leukotrienes - released by patrolling macrophages Histamine - released by basophils, platelets, and mast cells when they're exposed to either Complement fragment C3a or C5a - cause VD of arterioles

Diagnosis, treatment, and prevention of Dental Caries, Gingivitis, and Periodontal Disease

Caries - Diagnosed by visual inspection - Treat by filling cavities if caught early Gingivitis - Diagnosed by inspection of gums - Treat by scaling and use of antibacterial rinses - Prevention involves good oral hygiene

Disease at a Glance - Rubella

Cause: -- Rubivirus (rubella virus) (enveloped, positive, single-stranded RNA virus). Virulence factors: -- Attachment proteins, intracellular infection. Portal of entry: -- Respiratory tract. Signs and symptoms: -- Mild rash of pink to red macules and swollen lymph nodes in children. Causes severe congenital defects in unborn babies, including deafness, blindness, microcephaly, and mental and growth retardation. Incubation period: -- 7 to 14 days. Susceptibility: -- Unimmunized individuals and unborn babies. Treatment: -- There is no specific treatment for rubella other than supportive therapy. Prevention: -- Immunization with the combined MMR (measles, mumps, and rubella) vaccine. Pregnant women should not be given the live, attenuated vaccine.

Review - What are the 2 parts of the nervous system?

Central Nervous System Peripheral Nervous System

Review - Which viral gastroenteritis can be prevented by immunization? A. That of astrovirus. B. That of sapovirus. C. That of norovirus. D. That of rotavirus.

D - A live attenuated vaccine protects against severe rotavirus cases.

Review - If an unimmunized person has possibly been exposed to the bacterium that causes tetanus, the patient is given both active and passive immune treatment against tetanus. Why are they both necessary? A. An active immune treatment protects a patient against serum sickness that may be caused by a passive immune treatment. B. Taken alone, neither of the two treatments is strong enough to protect the patient, but together they are. C. During the time it takes for the patient's body to develop an active immune response, the passive immunity neutralizes any free-floating tetanus toxin. D. Passive immunity is necessary to activate the active immune component.

During the time it takes for the patient's body to develop an active immune response, the passive immunity neutralizes any free-floating tetanus toxin. - The ready-made antibodies of passive immunity antitoxin will protect the patient against the effects of the toxin until the patient's immune system has generated its own active immune response.

In which location within the cell are epitopes bound to MHC class I proteins? - Nucleus - Golgi body - Endoplasmic reticulum - Cytoplasm

Endoplasmic reticulum - It is within the endoplasmic reticulum that endogenous antigen is bound to the MHC class I protein.

Review - List the virulence factors of Staphylococcus aureus.

Enzymes - coagulase, staphylokinase, lipase, beta-lactamase (in 90% of strains) Factors that inhibit phagocytosis - polysaccharide slime layer (capsule), Protein A on cell surface Toxins - cytolytic toxins, leukocidin, epidermal cell differentiation inhibitor, exofoliative toxin (in some strains), toxic shock syndrome toxin (in some strains)

Bacterial Pneumonia Manifestations

Fever, chills, congestion, cough, chest pain, rapid breathing, and possible nausea and vomiting

Viral Pneumonia Manifestations

Fever, chills, mucus-producing cough, headache, body aches, fatigue

Inhalation Anthrax (bacterial) Manifestations

Fever, malaise, cough, chest discomfort, vomiting

"Strep" Throat (bacterial) Manifestations

Fever, red and sore throat, swollen lymph nodes in neck

Released During Degranulation

Histamine, Kinins, Proteases

Review - Activation of which type of lymphocytes results in the production of memory cells? A. Basophils and eosinophils B. Neutrophils and helper T cells C. Macrophages and dendritic cells D. Immature B and cytotoxic T cells

Immature B and cytotoxic T cells - Immature B cells mature into antibody-producing plasma cells and memory B cells - immature cytotoxic T cells mature into active cytotoxic T cells and memory T cells.

Clonal deletion of T cells

Immature T cells undergo one of four fates 1. T cells that do not recognize body's MHC protein undergo apoptosis 2. T cells that recognize autoantigen die by apoptosis 3. Some "self-recognizing" T cells become regulatory T cells 4. T cells that recognize MHC protein and foreign epitopes become repertoire of protective T cells (don't recognize autoantigen with MHC)

Titer

In serology, a measure of the level of antibody in blood serum, determines by titration and expressed as a ration reflecting the dilution

Review - What type of assay is used to identify syphilis and mononucleosis? A. Agglutination B. Indirect fluorescent antibodies C. Complement fixation D. Immunoblot

Indirect fluorescent antibodies are used to identify syphilis and mononucleosis.

Sties

Infections of the sebaceous glands near the eye - Staphylococcus aureus infections of sebaceous glands in the skin near the eye

Ophthalmianeonatorum

Inflammation of the conjunctiva and cornea of a newborn - Neisseria gonorrhoeae, a sexually transmitted bacterium - Babies can be infected during passage through a diseased birth canal

Keratitis

Inflammation of the cornea - Acanthamoeba, a protozoan, can cause both conjunctivitis and keratitis - treat with topical antimicrobial drugs - no antiviral drug available

Synthesized in Response to Allergen-IgE Binding

Leukotrienes Prostaglandins

Which of the following is a component of a B cell receptor but NOT a T cell receptor? - an antigen-binding site - a transmembrane portion - light chains - a variable region

Light chains are associated only with B cell receptors

Prevention of Staphylococcal Scalded Skin Syndrome (SSSS)

Little can be done to prevent SSSS because S. aureus is normally on skin, and susceptible patients lack sufficient immunity.

Based on the animation, T cells recognized the antigen displayed by what protein of the B cell? - CD4 - MHC - Antigen - TCR - BCR

MHC

Which of the following cells is included as an antigen-presenting cell? - Hepatocytes - Red blood cells - Platelets - Macrophages

Macrophages - The macrophage or "large eater" is responsible for internalizing, lysing, and then presenting exogenous antigen

Review - Which disease is also known as German measles? A. Chickenpox. B. Papillomas. C. Shingles. D. Rubella

Rubella is also known as German measles and as three-day measles

2 Pathways of Cytotoxic T Cell Killing

Perforin-granzyme pathway - involves the synthesis of special killing proteins - perforins and granzymes are released from Tc cell vesicles - granzymes enter the infected cell via perforin complex pore & activate enzymes of apoptosis CD95 pathway - mediated through a integral glycoprotein (Fas) found on the body's cells - binding of CD95L (receptor) on the Tc cell activates the enzymatic portion of the infected cell's CD95 such that apoptosis is induced

Pinworm Infestations

Pinworms are nematodes - Long, thin, unsegmented, cylindrical helminth - Perianal itching, irritability, decreased appetite - One-third of cases are asymptomatic - Caused by Enterobius vermicularis - Females deposit eggs in the perianal region at night - Eggs can be dislodged and spread the disease - Infections commonly occur in children - Enterobius is the most common parasitic worm in the U.S. - Diagnosis based on identification of eggs or adult pinworms - Treatment with pyrantel pamoate or mebendazole - Prevention requires strict personal hygiene

Why are smokers more likely to have infections with respiratory pathogens? - Smokers do not produce lysozyme in their mucus. - Respiratory pathogens produce substances that react with tobacco smoke. - Poisons and tars in tobacco smoke damage ciliated columnar cells. - Smokers do not produce as much mucus as do nonsmokers.

Poisons and tars in tobacco smoke damage ciliated columnar cells. - Tobacco smoke contains substances that damage ciliated cells in the respiratory tract. This makes it more difficult for smokers to clear their lungs of potential pathogens.

Review - What is the difference between an agglutination test and a precipitation test? A. Precipitation tests work on soluble antigens, while agglutination tests are used for insoluble antigens. B. An agglutination test involves measuring the turbidity of a mixture of antibodies and antigen. C. A precipitation test is to quantify antigen, while an agglutination test is not. D. Precipitation involves the use of red blood cells, while agglutination does not.

Precipitation tests involve movement of soluble antigen through agar, while agglutination tests involve the clumping of insoluble particles

4 Phases of Syphilis

Primary syphilis - Small chancre (sore) at site of infection --> A small, painless, reddened, hard lesion called a chancre forms at the site of infection 10-21 days following exposure. Although chancres typically form on the external genitalia, about 20% form in the mouth, around the anus, or on the fingers, lips, or nipples. Chancres are often unobserved, especially in women, in whom these lesions frequently form on the cervix. Chancres last three to six weeks Secondary syphilis - Sore throat, headache, fever, lymphadenopathy (diseased lymph nodes), malaise, rash (does not itch or hurt, but persists for months) Latent syphilis - No symptoms, may last 10+ years Tertiary syphilis - May take 3-15 years. Dementia, blindness, paralysis, heart failure, or gummas. Result of years of untreated infection. --> syphilitic gummas are rubbery, swollen lesions that can occur in bones, in nervous tissue, or on the skin --> rarely develop in patients in countries where antimicrobial drugs are available

Acquired Immunodeficiency Diseases (5)

RESULT FROM: - old age; T cell production slows; immunity, especially cell-mediated immunity, is normally less effective in older individuals than in younger individuals - severe stress --> Excess production of corticosteroids (toxic to T cells) suppresses cell-mediated immunity - Malnutrition and environmental factors --> Inhibit production of B cells and T cells

Characteristics of HIV That Challenge the Immune System

Retrovirus with a genome that consists of two copies of +ssRNA - Reassortment of viral genes possible; reverse transcription produces much mutation and thus genetic variation; genome integrates into host's chromosome Targets helper T cells especially, but also macrophages, dendritic cells, and muscle cells, and possibly liver, nerve, and epithelial cells - Permanently infects key cells of host's immune system Antigenic variability - Antigenic variabilityNumerous antigenic variations due to mutations help virus evade host's immune response Induces fusion of infected cells with neighboring cells - Increases routes of infection; intracellular site helps virus evade immune detection

Review - List the virulence factors of Staphylococcus epidermis.

S. epidermis lacks virulence factors and rarely causes disease. It only has a polysaccharide slime layer (capusle) that inhibits phagocytosis.

2 Steps of Type 1 Hypersensitivity Reaction

Sensitization 1. APC phagocytizes and processes allergen 2. APC presents epitope to Helper T cell 3. IL-4 from Helper T cell stimulates/activates selected B cell clone 4. B cells become plasma cells that secrete IgE 5. IgE stem binds to mast cells, basophils, and eosinophils Degranulation - occurs AFTER mast cells, basophils, and eosinophils are sensitized - IN RESPONSE TO SUBSEQUENT EXPOSURE, Degranulation releases histamine, kinins, proteases, leukotrienes, and prostaglandins

Common Cold (viral) Manifestations

Sneezing, rhinorrhea, congestion, sore throat, headache, malaise, cough

Review - What is the function of stem cells within the respiratory epithelium?

Stem cells in the respiratory epithelium undergo cytokinesis to form both ciliated cells and goblet cells to replace those lost during normal shedding.

In the thymus, T cells randomly generate different __________ with a particular shape - MHC proteins - epitopes - T cell receptors - cytotoxins

T cell receptors - In the thymus, each T cell generates a different T cell receptor resulting in a great variety of T cells, each specific for recognizing a different antigen.

The responses observed in type IV hypersensitivities result from the action of - T cells and phagocytes. - IgG and complement. - IgE antibodies and mast cells. - autoantibodies. - inflammatory chemicals.

T cells and phagocytes

Why do physicians collect CSF from the lower back and not from higher up the vertebral column?

The lower vertebral column does not contain the spinal cord; therefore, the physician will not damage the CNS or likely introduce microbes into the CNS. Further, the lumbar vertebrae are large, are easy to identify, and have larger spaces between them.

If a microbe were capable of preventing a phagosome from fusing with a lysosome, which of the following would occur? - The microbe would cause the phagocyte to go through apoptosis. - The microbe would be expelled from the residual body. - The microbe would be killed by the lysosome's enzymes. - The microbe would survive inside the phagocyte.

The microbe would survive inside the phagocyte

Review - Which route of pathogen transmission bypasses the skin and mucous membranes to deposit microbes directly into the tissues underneath? A. Respiratory droplet transmission. B. The parenteral route. C. Direct contact. D. Airborne transmission.

The parenteral route of pathogen transmission circumvents the skin and mucous membranes. Pathogens that enter via the parenteral route of transmission bypass the protective layers of the skin and mucous membranes, and are deposited directly into the tissues underneath. Pathogen entry through skin punctures by nails or needles are examples of transmission through the parenteral route.

What is apoptosis? - The process of programmed cell death. - The receptor on a cytotoxic T-cell that recognizes MHC molecules. - A protein molecule that forms a pore in the membranes of infected cells. - The proliferation of cytotoxic T-cells.

The process of programmed cell death.

Which of the following best characterizes clonal selection? - The production of identical B cells producing the same antibody - The production of identical T cells producing the same antibody - The production of identical B cells producing different antibodies - The production of different antigens by the same B cell

The production of identical B cells producing the same antibody

2. Blotting - Second Step of Immunoblot

The protein bands are transferred to an overlying nitrocellulose membrane. This can be done by absorbing the solution into absorbent paper—a process called blotting. The nitrocellulose membrane is then cut into strips

Review - Which part of an antibody is responsible for recognizing a specific antigen? A. An epitope B. A hinge region C. Constant regions of the heavy chains D. The variable regions of the light and heavy chains

The variable regions of the light and heavy chains of antibodies recognize a specific antigen. The variable regions of the light and heavy chains of antibodies is where antigen binds. This results in agglutination, antibody-dependent cell-mediated cytotoxicity, complement activation, neutralization, or opsonization, depending on the type of antibody class involved.

Uncoating of HIV

The viral envelope fuses with the vesicle's membrane, and the intact capsid of HIV enters the cytosol. The virus then uncoats the capsid and releases its two ssRNA molecules from the capsid into the cell's cytoplasm.

What is the fate of activated cytotoxic T-cells? - They can mature and attack infected cells. - Each activated cytotoxic T-cell proliferates, forming a clone of cells specific to the same antigen. - They proliferate into a clone of cells specific to the same antigen; some of these cells then differentiate into long-lived memory T-cells, while others mature to attack infected cells. - They can differentiate into long-lived memory T-cells. - They are destroyed via apoptosis. - They are infected by viruses.

They proliferate into a clone of cells specific to the same antigen; some of these cells then differentiate into long-lived memory T-cells, while others mature to attack infected cells.

Which of the following statements regarding toxoids is FALSE? - They provide lifelong immunity. - They stimulate antibody immune responses. - They are produced against the toxin of the microorganism rather than the microorganism itself. - They are chemically or thermally modified. - They have few antigenic determinants.

They provide lifelong immunity

Pseudomonas aeruginosa rarely causes disease. T/F

True! - despite its many virulence factors and ability to live in almost every moist environment using a wide variety of carbon sources, it rarely causes disease - The reason it is only a rare opportunist and not a common and formidable pathogen is that P. aeruginosa cannot penetrate the intact structures, cells, and chemical defenses of the skin - fortunate, because the ubiquity and inherent resistance of Pseudomonas to a wide range of antimicrobial agents would make a more virulent microbe an almost insurmountable challenge to health care professionals

Review - A doctor uses a sharp object to poke a patient's skin to determine whether the sense of touch has been lost. What disease is the doctor testing for? A. Tuberculoid leprosy. B. Meningococcal meningitis. C. Tetanus. D. Botulism.

Tuberculoid leprosy results in loss of sensation in areas of the skin.

Release of HIV

Two molecules of genomic RNA, molecules of tRNA, and several viral polypeptides bud from the host's cytoplasmic membrane to form an immature virion.​

HHV-1

Usual Diseases: 90% of cold sores/fever blisters; whitlow Mode of Transmission: Close contact Site of Latency: Trigeminal and brachial ganglia Location of Lesions: Face, mouth, and, rarely, trunk Other Complications: 15% of genital herpes cases; pharyngitis; gingivostomatitis, ocular/ophthalmic herpes; herpes gladiatorum; 30% of neonatal herpes cases

Review - How is blindness due to infectious disease prevented in newborns? A. By screening mothers for infectious disease and treating them with antibiotics. B. By prophylactic administration of antibiotics immediately after birth. C. Immunization of mothers during pregnancy and infants right after birth. D. Teaching expectant mothers good hygiene and how to prevent contracting sexually transmitted infections.

V - In most countries, infants receive antibiotic eyedrops immediately after birth to prevent blindness due to chlamydia or gonorrhea.

Why are some vaccines not recommended? Why? (2)

Vaccines against anthrax, cholera, plague, tuberculosis, etc. - CDC does not recommend them for the general U.S. population because the risk for these diseases is low

Characteristics of Some Viral Hemorrhagic Fevers: Ebola

Viral Genus (Family): Ebolavirus (Filoviridae) Natural Host(s): Probably bats Vector: None Geographical Distribution: Central Africa, research facility in the U.S.A. (Virginia), medical facility in the U.S.A. (Texas)

What does a vaccine contain? - Weakened or killed pathogen or parts of a pathogen - T cells against a pathogen - Live active pathogens - B cells against a pathogen

Weakened or killed pathogen or parts of a pathogen

Inactivated (Killed) Vaccines - Types of Vaccines

Whole agent vaccines - produced with inactive but whole microbes - Ex. Rabies or Hep A vaccines Subunit vaccines - produced with antigenic fragments of microbes

Can attenuated viruses mutate?

YES - Occasionally, attenuated viruses actually revert to wild type or mutate to a form that causes persistent infection or disease

Can lymphocytes be differentiated by fluorescent dyes? (3)

Yes! - Scientists routinely identify and separate types of white blood cells by using specific monoclonal antibodies produced against each cell type - researchers can attach differently colored fluorescent dyes to the antibodies, allowing them to differentiate types of lymphocytes by the color of the dye carried by each type of antibody - critical in diagnosing disease and monitoring its progression and effectiveness of treatment in patients with AIDS, other immunodeficiency diseases, leukemias, and lymphomas

Can newly immunized patients infect others? What does this do?

Yes! it provides Contact Immunity

nephelometry

a machine measures the amount of light reflected from antigen-antibody complexes within the solution

Antibody

a protective protein secreted by descendants of a B cell that recognizes and strongly binds to the specific biochemical shape of the antigen

In regard to antibody function, identify the MISMATCHED pair - opsonization = simulates phagocytosis - neutralization = covering a critical portion of a toxin so that it is no longer harmful - antibody-dependent cell-mediated cytotoxicity = target cell dies by apoptosis - agglutination = antibodies bind microbes to the vessel walls inhibiting spread of the microbe

agglutination = antibodies bind microbes to the vessel walls inhibiting spread of the microbe - Agglutination causes soluble molecules to become insoluble, which may target them for phagocytosis or filtering by the kidneys

C3a and C5a

also trigger the release of other inflammatory chemicals

antilymphocyte antibodies

alter immune reactivity

May components of the 2nd line of defense either are contained in or originate in the ___.

blood (complex liquid tissue composed of cells and portions of cells within plasma)

The ability of a specific immune cell to proliferate and form many generations of nearly identical cells is called __________. - specificity - memory - clonality - inducibility

clonality - Specific immune cells such as B cells make a huge impact on the immune response, in part because of their ability to rapidly clone themselves, a characteristic called clonality.

Exogenous antigens are processed for immune recognition by ________ cells. - helper T - all nucleated - dendritic - macrophage - dendritic and macrophage

dendritic and macrophage

The tuberculin response is an example of allergic contact dermatitis. T/F

false

The first and second lines of defense against microbial invasion are part of: - adaptive immunity. - innate immunity. - microbial antagonism. - species resistance. - both species resistance and adaptive immunity.

innate immunity

common point-of-care tests (3)

immunofiltration and immunochromatography assays - not quantitative - do rapidly give a positive or negative result, making them very useful in arriving at a quick diagnosis.

What are two hallmark characteristics of adaptive immunity?

inducibility and specificity

Where do adaptive immune responses initiate? - site of infection - lymph nodes

lymph nodes - because antigen-presenting cells interact with lymphocytes here

Diapedesis

leukocytes exit the blood to attack invading microbes in the tissues by squeezing between the cells lining capillaries

turbidimetry

light detector measures the amount of light passing through a solution

Lectin Pathway of Complement Activation

mannose sugar, which is found on the surfaces of fungi, bacteria, and viruses, attaches to activating molecules called lectins. This begins the series of enzyme activities as in the classical activation pathway, leading to a complement cascade

What type of immunity is produced by the body when a person contracts a disease? - artificially acquired passive immunity - naturally acquired active immunity - innate immunity - naturally acquired passive immunity - artificially acquired active immunity

naturally acquired active immunity

What is likely the worst infectious disease of all time?

smallpox - death rate as high as 33% - Edward Jenner is credited with inventing smallpox vaccination: the world's first immunization

Which of the following contributes to protecting the eyes from microbial invasion? - tears contain lysozyme and salt. - a mucus layer traps and removes microbes. - tears mechanically flush particles from the eyes. - tears contain lysozyme and salt and mechanically flush particles from the eyes. - tears and mucus combine to trap microbes and remove them.

tears contain lysozyme and salt and mechanically flush particles from the eyes

bulbar poliomyelitis - type of paralytic polio

the brain stem is infected, resulting in paralysis of respiratory muscles or of muscles in the limbs

A sick child may have influenza or RSV. These virus infections have different treatment options, so the physician requests antibody titer tests. The results are as follows: anti-influenza antibodies are primarily IgM, and anti-RSV antibodies are all IgA and IgG. Which of the following is the most appropriate interpretation? - the child has a current RSV infection and was previously exposed to influenza. - the child currently has influenza and has previously been exposed to RSV. - the child has concurrent influenza and RSV infections. - the child has neither influenza nor RSV. the results do not provide sufficient data to draw a conclusion.

the child currently has influenza and has previously been exposed to RSV

Opsonization is: - the sticking of monocytes to the wall of the blood vessels at the site of infection. - damage resulting in cell lysis. - nonspecific leukocyte secretion of toxins onto the surface of virally infected cells. - the coating of a pathogen by complement to facilitate phagocytosis. - phagocyte receptors detecting PAMPs.

the coating of a pathogen by complement to facilitate phagocytosis

Autoimmunity Affecting Endocrine Organs

the ensuing autoimmune reaction results in damage to or destruction of the gland and in hormone deficiencies as endocrine cells are killed - Ex. type 1 diabetes mellitus, Graves' disease

The name "antibody sandwich ELISA" refers to:

the fact that the antigen being tested for is "sandwiched" between two antibody molecules.

Due to the action of tears, potential pathogens of the eyes and its membranes usually end up where? - the stomach - the bloodstream - the lungs - the skin

the stomach - Tears (and the microbes collected by them) flow into the nose through a series of canals and ducts; here, they mix with nasal mucus and pass into the pharynx, where they are swallowed.

Can doctors use interferons to help patients?

they can administer interferons created using recombinant DNA techniques can activate immune responses to help patients fight viral infections and cancers

If you've never had chickenpox, can you catch it from someone with shingles?

yes The opposite is not true—a person cannot acquire shingles from a chickenpox victim.

Can adaptive immunity harm body cells?

yes! - the body regulates adaptive immune responses to prevent damage - Ex. an immune response requires multiple chemical signals before proceeding --> thus reducing the possibility that an immune response will be randomly triggered against uninfected healthy tissue --> Autoimmune disorders, hypersensitivities, or immunodeficiency diseases result when regulation is insufficient or overexcited

Shape of Antigens

- Recognized by three-dimensional regions called epitopes (antigenic determinants) --> the actual part of an antigen that determines an immune response

Primary Immunodeficiency Diseases

**Many different inherited defects have been identified in all of the body's lines of defense, affecting first and second lines of defense as well as antibody and cell-mediated immune responses. **Most primary immunodeficiencies are associated with defects in the components of the third line of defense—adaptive immunity - chronic granulomatous disease - severe combined immunodeficiency disease - DiGeorge syndrome - Bruton-type agammaglobulinemia

Pathogenesis of AIDS

**Only human cells replicate HIV effectively, and, as its name indicates, the virus causes destruction of a human's immune system. 1. Initially, there is a burst of virion production and release from infected cells --> Fever, fatigue, weight loss, diarrhea, and body aches accompany this primary infection 2. The immune system responds by producing antibodies, and the number of free virions plummets --> body destroys almost a billion virions each day, but cytotoxic T cells kill about 100 million virally infected CD4+CD4+ cells in the same time period. No specific symptoms accompany this stage, and the patient is often unaware of the infection. 3. Integrated viruses continue to replicate and virions are released into the blood to such an extent that the body cannot make enough helper T cells --> Over the course of 5 to 10 years, the number of helper T cells declines to a level that severely impairs the immune response. The rate of antibody formation falls precipitously as helper T cell function is lost. 4. HIV production climbs 5. Eventually the patient dies

How botulinum toxin acts at a neuromuscular junction

*Blocks release of acetylcholine - the many ends of a motor neuron forms a synapse with a muscle cell (neuromuscular junction) - neuron stores the neurotransmitter acetylcholine which mediates communication between neurons and muscle cells - The binding of ACh to the ACh receptor triggers a series of events inside the muscle cell that results in muscle contraction - Botulism toxins act by binding irreversibly to neuronal cytoplasmic membranes, thereby preventing the fusion of vesicles and the secretion of acetylcholine into the synaptic cleft - botulism neurotoxins prevent muscular contraction, resulting in a flaccid paralysis - BINDING IS IRREVERSIBLE - however, the blocked motor neuron's axon may grow new branches, which form new synapses with muscles

Toxins of Staphylococcus Aureus for Folliculitis (4)

*Cytolytic toxins disrupt the cytoplasmic membranes of a variety of cells - Leukocidin kills leukocytes, providing Staphylococcus with additional protection against phagocytosis - epidermal cell differentiation inhibitor is a protein that induces large holes in the linings of blood vessels, allowing access for the bacterium to invade body tissues - exfoliative toxin or toxic shock syndrome toxin—proteins that cause staphylococcal scalded skin syndrome and staphylococcal toxic shock syndrome

Pathogens of Arboviruses

*Six arboviruses cause most cases of viral encephalitis in Americans. Scientists name these viruses for the geographic regions where the diseases or viruses were first identified -- Eastern equine encephalitis (EEE), Western equine encephalitis (WEE), and Venezuelan equine encephalitis (VEE), all of which were first identified in horses in the eastern United States, western United States, and Venezuela, respectively. The viruses causing these conditions are all enveloped, +ssRNA viruses in the family Togaviridae -- St. Louis encephalitis and West Nile encephalitis, which were first identified in St. Louis, Missouri, and West Nile Province, Uganda (Africa), respectively. Their enveloped, +ssRNA viruses are in the family Flaviviridae; they differ from togaviruses in their antigens. West Nile virus (WNV), which arrived in the United States in 1999, has had the most impact on people in the United States. -- California (also known as LaCrosse) encephalitis, which is endemic to California but was first described from LaCrosse, Wisconsin. The virus, which is enveloped and has a segmented −ssRNA genome, is in the family Bunyaviridae. -- Physicians are concerned that new forms of viral encephalitis have appeared in Asia and Australia.

Opsonization - Antibody Function (5)

- "Changing the surface of an antigen so as to enhance phagocytosis" - Antibodies act as opsonins—molecules that stimulate phagocytosis - Neutrophils and macrophages have receptors for the stems of IgG molecules --> these leukocytes bind to the stems of antibodies --> Once antibodies are so bound, the leukocytes phagocytize them, along with the antigens they carry, at a faster rate compared to antigens lacking bound antibody

Agglutination - Antibody Function (4)

- "Numerous antibodies can aggregate antigens together" - each basic antibody has two antigen- binding sites, each can attach to two epitopes at once - Agglutination of soluble molecules typically causes them to become insoluble and precipitate - Agglutination may hinder the activity of pathogenic organisms and increases the chance that they will be phagocytized or filtered out of the blood by the spleen

Specificity of the T Cell Receptor (TCR) (5)

- 10 different kinds - TCR binds only one unique epitope - TCRs do not recognize epitopes directly - TCRs only bind epitopes associated with a MHC protein - TCRs act primarily against cells that harbor intracellular pathogens or abnormal body cells

Microbiome of the Lower small intestine and colon

- 100 trillion bacteria in total - In every gram of feces there is 100 billion bacteria. 40% of weight - Microbiota here are beneficial: microbial antagonism, produce vitamin B7, B9, B12, K - Mucous membrane prevents microbes entering the bloodstream - Most are Bacteroides, G- anaerobe --> Lactobacillus, Escherichia, Enterobacter, Proteus Klebsiella. Bifidobacterium, Clostridium, Shigella, Candida (fungus), Entamoeba (protozoan), Trichomonas (protozoan)

Anthrax (2)

- 3 distinct clinical manifestations (gastrointestinal, inhalation, and cutaneous) - Gastrointestinal anthrax is rare in humans

Phaeohyphomycosis - wound mycoses (10)

- 30+ genera of fungi cause this --> the more common are the ascomycetes Alternaria, Exophiala, Wangiella , and Cladophialophora. - acquired when spores, which are prevalent in indoor environments, including hospitals, enter open surgical or traumatic wounds - more variable in presentation than are chromoblastomycoses - paranasal sinus phaeohyphomycosis involves colonization of the nasal passages and sinuses --> occurs in allergy sufferers and AIDS patients - In cerebral phaeohyphomycosis, the fungus actively invades the brain --> most rare form that occurs only in the severely immunocompromised - some cases can be treated with itraconazole, but the disease is permanently destructive to tissues - Microscopic examination of stained skin scrapings, biopsy material, or cerebrospinal fluid (CSF) reveals brown-pigmented hyphae, which are diagnostic

Pathogen and Virulence Factors of Staphylococcal Scalded Skin Syndrome (SSSS) (3)

- 5% of strains of Staphylococcus aureus secrete one or two distinct exfoliative toxins that cause SSSS - Each toxin causes the dissolution of epidermal desmosomes (intercellular bridge proteins that hold together cytoplasmic membranes of adjoining cells) - both toxins affect keratinized cells of the epidermis

Chlamydial Infections

- 85% of women are usually asymptomatic - 75% of males have inflammation, painful urination, purulent discharge from penis - Lymphogranuloma venereum, a severe form of chlamydia, causes a genital lesion and bubo in the groin - Caused by Chlamydia trachomatis (G-) --> Developmental cycle: unable to synthesize ATP ----> Elementary bodies are the dormant, infective form. Resistant to environmental extremes ----> Reticulate bodies are the obligate intracellular reproductive form - Enter body through scrapes or cuts - Infect conjunctival cells or cells lining mucous membranes - Destruction of infected cells and inflammation - Reinfection in the same site with the same or similar strain causes a hypersensitive immune response which can cause blindness, sterility, or sexual dysfunction - Most common reportable STD in the U.S. - Detection of chlamydial DNA by PCR is diagnostic - Treated with doxycycline or erythromycin - Prevented by abstinence or mutual monogamy

Pathogens and virulence factors of Viral Meningitis

- 90% of cases caused by viruses in the genus Enterovirus (+ssRNA) --> Coxsackie A virus, Coxsackie B virus, Echovirus --> picornaviruses are very small, positive, single-stranded RNA (+ssRNA) viruses --> LACK ENVELOPES - Herpesviruses, mumps virus, and several other viruses may cause viral meningitis

antiretroviral therapy (ART) (5)

- A "cocktail"of several antiviral drugs --> nucleotide analogs, integrase inhibitors, protease inhibitors (e.g., darunavir), and reverse transcriptase inhibitors (e.g., emtricitabine) - Reduces viral replication, but infection remains --> stops the replication of HIV because strains of the virus are unlikely to develop resistance to all of the drugs simultaneously - expensive and generally must be taken on a strict schedule

Rubella (12)

- AKA "German measles" - AKA "3-day measles" - disease caused by infection with Rubivirus (rubella virus) (+ssRNA) - Spread by respiratory secretions, infects only humans - results in characteristic rash lasting about 3 days - slightly swollen lymph nodes and a mild rash of flat, pink to red spots (macules) - mild in children - Infections in adults are more severe and may result in arthritis or encephalitis --> Immune response to infected cells - potentially teratogenicto fetuses of infected women --> cardiac abnormalities, deafness, blindness, mental retardation, microcephaly, growth retardation, and death --> the virus can move across the placenta even when the mother is asymptomatic

Streptococcus agalactiae - pathogen of bacterial meningitis

- AKA "Lancefield group B Streptococcus" (based on its so-called B antigen) - a normal member of the vaginal microbiota in about a third of all women --> acquired at birth - protective capsule that allows it to evade phagocytosis when it gets into the blood - causes bacteremia, pneumonia, and meningitis in newborns.

conjunctiva

- An extension of the epidermis of the skin - lines the backside of the eyelids and all but the center of the cornea

Pathogens and Virulence Factors of African Viral Hemorrhagic Fevers

- Caused by genera Ebolavirus or Marburgvirus - (-ssRNA) --> enveloped viruses have long filamentous capsids, which sometimes curve back upon themselves - Lassa virus has two RNA molecules with filamentous capsids surrounded by a roughly spherical envelope

tuberculin response - Type 4 (9)

- AKA "Mantoux test" - Skin exposed to tuberculosis or tuberculosis vaccine reacts to an injection of tuberculin beneath the skin - Used to diagnose contact with antigens of M. tuberculosis --> No response when individual not infected or vaccinated --> Red, hard swelling develops in individuals previously infected or immunized (10mm+ = positive response) - Response mediated by memory T cells that cause a slowly developing inflammation --> phagocytic cells migrate to the site and attract memory T cells, which secrete a mixture of cytokines that attract still more T cells and macrophages, giving rise to a slowly developing inflammation --> macrophages ingest and destroy the injected tuberculin, allowing the tissues to eventually return to normal - lesion reveals that it is infiltrated with lymphocytes and macrophages

Type I hypersensitivities (7)

- AKA "allergies" - antigens are "allergens" - IMMEDIATE --> develop within seconds or minutes following contact with antigens - local or systemic (whole body) - result from the release of inflammatory molecules (ex. histamine) in response to an antigen - Reaction is a 2-step process

Acute Anaphylaxis (5) - SYSTEMIC

- AKA "anaphylactic shock" - condition in which the release fo inflammatory mediators overwhelms the body's coping mechanisms, causing suffocation, edema, smooth muscle contraction, and often death - Following a sensitized individual's contact with an allergen, many mast cells may degranulate simultaneously, releasing massive amounts of histamine and other inflammatory mediators into the bloodstream ---> release of chemicals may exceed the body's ability to adjust - rapid and potentially fatal

Brucellosis

- AKA "bang's disease"; "Malta fever"; "rock fever of Gibraltar"; "fever of Crete" (all named after localized epidemics) - zoonosis - disease caused by Brucella - usually asymptomatic or mild, though it can result in sterility or abortion in animals - luctuating fever that spikes at about 40°C (104°F) every afternoon --> AKA "undulant fever" - chills, sweating, headache, myalgia (muscle pain), and weight loss

Skin (8)

- AKA "cutaneous membrane" - prevents excessive water loss - helps regulate body temperature via the production of sweat and the dilation or constriction of blood vessels - helps form vitamin D - involved in sensory phenomena - barrier against microbial invaders - covers 2 sq meters; 0.05 mm on the lips to 4.0 mm thick on the soles of the feet - 2 distinct layers (superficial epidermis and deep dermis)

ELISAs - labeled immunoassay

- AKA "enzyme-linked immunosorbent assay" - the label is an enzyme that reacts with its substrate to produce a colored product that indicates a positive test - used to detect the presence and quantify the abundance of antibodies in serum (indirect testing) - Ex. Lyme disease, legionellosis (a type of pneumonia), or cat scratch disease

Pyrogenic Toxins (4)

- AKA "erythrogeic toxins) - proteins that stimulate macrophages and helper T lymphocytes to release cytokines --> stimulate fever, a widespread rash, and shock - - virulence factor of Streptococcus pyogenes (group A Streptococcus)

Oral herpes

- AKA "fever blisters", "cold sores" - Painful, itchy, creeping skin lesions on the lips - Fever blisters appear one to two weeks after exposure to an infected individual - Initial infections may be accompanied by flulike symptoms such as malaise, fever, and muscle pain - fluid-filled lesions eventually break, crust over, and fall off (within 7-10 days) to reveal pink healing skin - Subsequent lesions are generally milder - herpetic gingivostomatitis; Severe infections in which the lesions extend into the oral cavity --> often seen in young patients and in patients with lowered immune function due to disease, chemotherapy, or radiation treatment - herpetic pharyngitis; pharynx becomes infected and inflamed - herpes esophagitis; characterized by extremely painful and difficult swallowing, fever, and sometimes chills --> Immunosuppressed individuals may develop this

Erthema Infectosium (8)

- AKA "fifth disease" --> it was the fifth childhood rash on a list used by pediatricians in the early 1900s - respiratory disease caused by a single-stranded DNA (ssDNA) virus called B19 virus in the genus Erythrovirus, family Parvoviridae - manifests as an infectious reddening of the skin - begins on the cheeks and spreads to the arms, thighs, buttocks, and trunk - facial rash appears as if the patient has been slapped, a characteristic that child protection workers could misinterpret - Sunlight aggravates the rash at all stages; faded, early lesions can reappear when the patient is exposed to sunlight - treat with nonsteroidal anti-inflammatory drugs (NSAIDs)

Shingles (7)

- AKA "herpes zoster" - Stress, aging, or immune suppression reactivates the viruses in 15-20% of individuals who have had chickenpox - Reactivated viruses travel down the nerve they inhabit and produce an extremely painful skin rash near the end of the nerve --> forms in the band of skin associated with the nerve or in the eye - lesions are accompanied by a burning sensation, numbness, itchiness, or intense pain - After the scabs of shingles fall off, most people have no further skin manifestations, though the pain associated with shingles may remain for months or years after the lesions have healed --> Some patients report that the pain is so intense they cannot wear clothing over the affected area for months or years

Urticaria (4) - LOCAL

- AKA "hives" - raised, red areas on the skin - a result of the release of histamine and other mediators, plus the ensuing leakage of serum from local blood vessels - the lesions are very itchy because histamine irritates local nerve endings

Infectious Mononucleosis

- AKA "kissing disease" or "mono" - a condition resulting from interactions of a patient's cellular immune system with infected B lymphocytes - Severe sore throat and fever occur initially - Followed by swollen lymph nodes, severe fatigue, appetite loss, and a skin rash anywhere on the body

Tetanus

- AKA "lockjaw" - Spasms and contractions may spread to other muscles - If the toxin spreads to neurons that control glands and involuntary muscles, then heartbeat irregularities, fluctuations in blood pressure, and extensive sweating result - Complete, unrelenting contraction of the diaphragm results in a final inhalation—patients die because they cannot exhale

Warts (7)

- AKA "papillomas" - generally benign growths of the epithelium of the skin or mucous membranes - painless, though they may itch or hurt, particularly plantar warts - form on many body surfaces - More than 100 different strains of Papillomavirus cause warts --> Various strains infect either cutaneous or mucosal tissues, causing infected epithelial cells to divide --> Some strains of papillomaviruses integrate into host cell chromosomes, potentially triggering the action of oncogenes, which cause cancers.

Impetigo (8)

- AKA "pyoderma" - caused by infection with Staphylococcus aureus (mostly) or Streptococcus pyogenes --> S. aureus acting alone causes about 80% of impetigo cases, and about 20% of cases involve Streptococcus pyogenes alone or in conjunction with S. aureus --> The bacteria invade where the skin is compromised (Scratches, abrasions, cold sores etc.) - a contagious disease characterized by small, flattened, red patches that appear primarily on the face and limbs, particularly of children whose immune systems are incompletely developed - patches develop into oozing, pus-filled vesicles on a red base --> vesicles eventually break and form a thick, honey-colored, sticky crust that is attached firmly to the skin and may cause intense itching - Numerous vesicles at various stages of development characterize impetigo because bacteria from a vesicle spread to adjacent sites on the skin

dermatophytoses - cutaneous mycoses

- AKA "ringworm" but NOT caused by a worm - AKA "tineas" - most common type of cutaneous mycoses - caused by dermatophytes --> fungi that grow on skin, nails, and hair and invade the body form cutaneous lesions that grow in the skin - use keratin as a nutrient source - stimulate cell-mediated immune responses that damage deeper tissues --> (Such triggering of immune responses distinguishes dermatophytoses from superficial fungal infections) - Most dermatophytoses are clinically distinctive and so common that they are readily recognized - Ex. Athlete's foot

Sporotrichosis - wound mycoses (9)

- AKA "rose gardener's disease" - Sporothrix schenckii is a dimorphic ascomycete - subcutaneous infection usually limited to the arms and legs - resides in the soil and is most commonly introduced in wounds by thorn pricks or wood splinters - Avid gardeners, farmers, and artisans who work with natural plant materials have the highest incidence - Fixed sporotrichosis initially appears as painless, nodular lesions that form around the site of inoculation --> With time, these lesions produce a pus-filled discharge, but they remain localized and do not spread - lymphocutaneous sporotrichosis; the fungus enters the lymphatic system near the site of a primary lesion, giving rise to secondary lesions on the skin surface along the course of lymphatic vessels --> fungus remains restricted to subcutaneous tissues and does not enter the blood.

Measles (8)

- AKA "rubeola" - AKA "red measles" - the most contagious and one of the more serious childhood diseases (not to be confused with rubella) - fever (greater than 40 C), sore throat, runny nose, rash, headache, dry cough, and conjunctivitis (inflammation of the lining of the eyelid) (all last about 9 days) - after 2 days of illness, lesions called Koplik's spots appear on the mucous membrane of the mouth (appear 2-3 days before rash) --> These lesions, which have been described as crystals of salt surrounded by a red halo, last one to two days and provide a definitive diagnosis of measles - Red, raised (maculopapular) lesions then appear on the head and spread over the body - these later lesions, which initially are similar to those of rubella, are extensive and often fuse to form red patches, which gradually turn brown as the disease progresses

viral gastroenteritis

- AKA "stomach flu" - inflammation of the mucous membrane of the stomach and intestines, caused by a viral pathogen - general manifestations the same as for bacterial gastroenteritis—abdominal pain and cramping, diarrhea, nausea, and vomiting. - Additional signs and symptoms may include fever, chills, clammy skin, weight loss, or lack of appetite. - Dehydration is the most common complication. - Symptoms generally appear within 24 hours of consuming contaminated food and resolve within 12-60 hours. - Vomiting, bloody stool, life-threatening diarrhea, and dysentery may occur with viral gastroenteritis.

Toxoplasmosis

- AKA "toxo" - major disease seen in AIDS patients - Unborn children are also at risk - a disease affecting animals caused by infection with Toxoplasma gondii - in humans, characterized by mild, febrile symptoms but may be fatal in AIDS patients - transplacental transmission may result in miscarriage, stillbirth, or severe birth defects - - Majority (80%) of cases have no symptoms and resolves spontaneously within a year. - Symptoms in individuals with poor immunity --> Fever, malaise, inflammation of the lungs, liver, and heart. Headache, confusion, spastic paralysis, blindness, myocarditis, encephalitis, and death

Coccidioidomycosis

- AKA "valley fever" - occurs primarily in the San Joaquin Valley of California - major manifestation is pulmonary, initially resembling pneumonia or tuberculosis, though about 60% of patients experience only mild, unremarkable respiratory symptoms that typically resolve on their own - Other patients develop more severe infections characterized by fever, cough, chest pain, difficulty breathing, coughing up or spitting blood, headache, night sweats, weight loss, and pneumonia; in some individuals, a diffuse rash may appear on the trunk - fungus spreads from the lungs in severely immunocompromised patients

Chickenpox (8)

- AKA "varicella" - 2-3 weeks after infection with chickenpox virus, the patient develops a slight fever and characteristic skin lesions on the back and trunk that then spread to the face, neck, and limbs - severe cases, the rash may spread into the mouth, pharynx, and vagina - lesions begin as macules, progress in one to two days to papules, and finally become thin-walled, fluid-filled vesicles on red bases - vesicles turn cloudy, dry up, and crust over in a few days - Successive crops of lesions appear over a three- to five-day period, so that at any given time all stages can be seen - Usually chicken-pox is not life threatening, though it can, rarely, be fatal to newborns - can become latent within sensory nerves and may remain dormant for years

Primary Atypical (Mycoplasmal) Pneumonia

- AKA "walking pneumonia" due to mild symptoms - the leading type of pneumonia in children and young adults - fever, malaise, headache, sore throat, and excessive sweating, are not typical of other types of pneumonia - body responds to infection with a persistent, unproductive cough in an attempt to clear the lungs - may last for several weeks, but it is usually not severe enough to require hospitalization or to cause death

Immunoblot - labeled immunoassay (4)

- AKA "western blot" - technique used to detect a specific protein, such as an antibody, in a complex mixture - used to confirm the presence of proteins, including antibodies against pathogens. - Ex. used to verify the presence of HIV proteins or antibodies against the bacterium of Lyme disease in the blood serum of patients

Poliomyelitis (polio)

- After being ingested and subsequently infecting pharyngeal and intestinal cells, poliovirus travels via the lymph and blood to infect cells of the CNS, particularly of the spinal cord - causes one of four conditions - polioviruses are stable for prolonged periods in swimming pools and lakes and can be acquired by swallowing contaminated water, parents in the 1930s and 1940s often feared to let their children swim

Pathogenesis and Epidemiology of inhalation anthrax

- An infective dose of B. anthracis endospores involves inhalation of at least 8000 to 50,000 endospores - In the lungs, the endospores germinate, and vegetative cells secrete anthrax toxin, which impairs respiratory function, initiates toxemia, and often results in death - does NOT spread from person to person - people must acquire B. anthracis from infected animals either by contact or via inhalation of endospores in dust or on animal hides or wool - most patients die

Behaviors that increase the risk of HIV infection include the following (4)

- Anal intercourse, especially receptive anal intercourse - Sexual promiscuity; that is, sex with more than one partner - Intravenous drug use - Sexual intercourse with anyone in the previous three categories

Anisakiasis

- Anisakiasis results from infestation by several parasitic nematodes - Typically asymptomatic - Abdominal pain, nausea, vomiting, and fever may occur - Some individuals develop an allergic rash - Most commonly caused by Anisakis simplex - Complex life cycle with several larval stages - About 20,000 cases occur worldwide - Diagnosis is generally made using endoscopy to visualize worms - Treatment involves removing worms from the intestine by endoscopy or surgery - Prevented by avoiding raw and undercooked marine fish

Neutralization - Antibody Function (2)

- Antibodies can neutralize a toxin by binding to a critical portion of the toxin so that it can no longer harm the body - antibodies can block adhesion molecules on the surface of a bacterium or virus, neutralizing the pathogen's virulence because it cannot adhere to its target cell

Antibody-dependent cell-mediated cytotoxicity (ADCC) - Antibody Function (4)

- Antibodies often coat a target cell by binding to epitopes all over the target's surface - antibodies' stems can then bind to receptors on NK cells (not B or T cells) - similar to opsonization in that antibodies cover the target cell - however, with ADCC the target dies by apoptosis, whereas with opsonization the target is phagocytized

Antigen Processing

- Antigens processed for MHC proteins to display epitopes - Different processes for endogenous and exogenous antigens

Septicemia

- Any microbial infection of the blood that produces illness - bacteria are the most common cause

B Lymphocytes

- Arise and mature in the red bone marrow - Found primarily in the spleen, lymph nodes, and MALT - Small percentage of B cells circulates in the blood - Major function is the secretion of antibodies --> B cells differentiate into plasma cells, and plasma cells secrete antibodies

Vaccines using recombinant gene technology - Types of Vaccines (7)

- Attempts to make vaccines more effective, cheaper, safer - Variety of techniques used to improve vaccines --> might selectively delete virulence genes from a pathogen, producing an irreversibly attenuated microbe, one that cannot revert to a virulent pathogen - recom. techniques can produce large quantities of very pure antigens for use in vaccines --> scientists isolate the gene that codes for an antigen and insert it into a bacterium, yeast, or other cell, which then expresses and releases the antigen - Alternatively, a genetically altered microbial cell or virus may express the antigen and act as a live vaccine - Ex. recombinant DNA vaccine against Blastomyces in dogs is the first vaccine against a fungal pathogen

Bruton-type agammaglobulinemia - Primary Immunodeficiency Diseases (3)

- B cell deficiency - inherited disease in which affected babies, usually boys, cannot make immunoglobulins - children experience recurrent bacterial infections but are usually resistant to viral, fungal, and protozoan infections

Endocarditis

- Bacterial colonization of the endocardium triggers inflammation - causes the formation of Vegetations - Fever, fatigue, malaise, tachycardia - nonpainful hemorrhages on the soles of the feet or palms of the hands (Janeway lesions), or similar lesions that are painful (Osler's nodes) - may lead to complications such as blood clots, stroke, and the complete destruction of the heart valves, resulting in heart failure - commonly affects the left atrioventricular (mitral) valve, followed by the aortic semilunar valve. - symptoms of endocarditis may develop slowly over a period of weeks or months (subacute endocarditis) --> or they may develop quickly (acute endocarditis)

Epidemiology of Cat Scratch Disease (2)

- Bartonella is carried by cats but only causes disease in humans - relatively common and occasionally serious infection of children, affecting an estimated 32,000 children annually in the United States

Diagnosis, treatment, and prevention of Lyme Disease

- Based on the signs and symptoms of the disease --> Bacterium rarely detected in the blood - diagnosis is confirmed with ELISA and western blot tests to demonstrate the presence of antibodies against Borrelia - Antimicrobial drugs are used in the early phases --> doxycycline, cefuroxime, or amoxicillin effectively cures most cases of Lyme disease in the first phase - Treatment of later phases is difficult --> Symptoms often caused by the immune system and not active bacterial infection - Anti-inflammatory drugs act against the arthritic symptoms - Prevent with repellents containing DEET and protective clothing

Why is epinephrine and other drugs used to treat immediate hypersensitivity reactions ineffective against allergic contact dermatitis? (5)

- Because T cells mediate allergic contact dermatitis - these drugs have no effect because they do not alter the function of T cells - Epinephrine and antihistamines cannot stop a cytotoxic T cell from killing a cell, so they cannot be used for treatment - ACD helper T cells are activating other cells to attack the skin and helper T cells are also not affected by epinephrine/antihistamines - T cell activities and inflammation can, however, be suppressed by corticosteroid treatment

Pathogenesis of Common Cold

- Bind to ICAM-1 (membrane protein on cells in nasal cavities) and replicate in and then kill infected cells - Small size does not allow drugs or antibodies to bind - Rhinovirus infection proliferates in temperatures between 33-35 °(91-95F)

Blood Brain Barrier (5)

- Blood vessels on top of the pia mater (innermost of the three meninges) supply the CNS with blood --> walls of these blood vessels are composed of tightly joined cells that form the blood-brain barrier - prevents most microbes and large molecules in the blood from entering the subarachnoid space - blood infections do not easily spread to the CNS --> unfortunately, neither do many common antimicrobial drugs, such as penicillins, cephalosporins, tetracyclines, and aminoglycosides, making it more difficult to treat infections of the CNS

clinical signs of acute anaphylaxis are those of rapid suffocation (5)

- Bronchial smooth muscle contracts violently --> highly sensitive to histamine - increased leakage of fluid from blood vessels causes swelling of the larynx and other tissues - contraction of the smooth muscle of the intestines and bladder - without immediate administration of epinephrine, an individual in anaphylactic shock may suffocate, collapse, and die within minutes

Pathogenesis of Tetanus

- Can acquire through break in skin or mucous membrane --> they want access to deeper tissues, which lack free oxygen—an environment suitable for the germination of Clostridium endospores - Distance of infection from CNS determines incubation period (5 days to 15 weeks) - Tetanospasmin blocks the release of inhibitory neurotransmitters. With inhibition blocked, excitation of the motor neurons is unregulated, and the muscle is signaled to contract

Dental Caries, Gingivitis, and Periodontal Disease Signs and symptoms

- Caries: appear as holes or pits in the teeth - Gingivitis: non-destructive periodontal disease, gums that are swollen, tender, bright red, or bleeding - Periodontitis: untreated gingivitis, gums pull away from teeth and bone begins to be destroyed.

Leukotrienes (2)

- Cause slow, prolonged smooth muscle contraction, inflammation, and increased vascular permeability - lipid molecules that are powerful inflammatory agents

Pathogen and virulence factors of coronaviruses

- Caused by +ssRNA coronaviruses (CoV) - SARS-CoV - SARS-CoV-2 - MERS-CoV - Bats are natural host for SARS-CoV, camels appear to be host for MERS-CoV, unknown for SARS-CoV-2

Pathogen, pathogenesis, and epidemiology of Trachoma

- Caused by Chlamydia trachomatis(G-) --> Obligate, aerobic, intracellular parasite --> Multiplies in the conjunctiva cells and kills them, triggering a large amount of purulent (pus-filled) discharge that scars the conjunctiva - Such scarring in turn causes the patient's eyelids to turn inward, such that the eyelashes scratch, irritate, and scar the cornea - Corneal scarring triggers an invasion of blood vessels into this normally clear surface of the eye - scarred cornea that is filled with blood vessels is no longer transparent, and the eventual result is blindness - Typically affects children infected during birth - can infect adults when bacteria from the genitalia are introduced into the eyes via fomites, fingers, or flies

Pathogen and virulence factors of Diptheria

- Caused by Corynebacterium diphtheriae --> G+; pleomorphic due to snapping division - Virulence factors: --> Lysogenic phage codes for diphtheria toxin: enzymatically prevents polypeptide synthesis and causes cell death

Pathogens and virulence factors of Dengue Fever and Dengue Hemorrhagic Fever

- Caused by Dengue virus serotypes 1, 2, 3, and 4 --> DENV-1, DENV-2, etc. (+ssRNA). - Aedes mosquitos are the vector

Pathogen of Hantavirus Pulmonary Syndrome (HPS)

- Caused by Hantavirus (-ssRNA) - Transmitted from mice via inhalation

Pathogen and virulence factors of Peptic Ulcers

- Caused by Helicobacter pylori --> G-, genus has unique structure: helix to curved rod, but not a spirochete Numerous virulence factors - Inhibits acid production by stomach cells - Urease neutralizes stomach acid - Flagella enable burrowing through mucus lining - Adhesins facilitate attachment to gastric cells

Pathogen and virulence factors of Klebsiella Pneumonia

- Caused by Klebsiella pneumoniae --> G- bacillus; nonmotile - Produces a prominent capsule, giving Klebsiella colonies a mucoid appearance, protecting the bacterium from phagocytosis - an opportunistic pathogen that infects the respiratory systems of humans and animals following inhalation

Pathogen and virulence factors of Tuberculosis

- Caused by Mycobacterium tuberculosis --> Gram-positive rod with cell walls containing an abundance of Mycolic Acid - Acid-fast bacillus: if phagocytosed, mycolic acid prevents destruction and capable of intracellular growth - Virulent strains of M. tuberculosis produce cord factor, a cell wall component that produces strands of daughter cells that remain attached to one another in parallel alignments, inhibits migration of neutrophils, and is toxic to mammalian cells --> Mutant mycobacteria that are unable to synthesize cord factor do not cause disease

Pathogen and virulence factors of Spotted Fever Rickettsiosis (8)

- Caused by Rickettsia rickettsii --> G-, coccobacillus, intracellular parasite - they don't Gram-stain well so scientists use Gimenez-stained yolk sac smear - Rickettsias can't use glucose; they must oxidize amino acids and citric acid cycle intermediates, such as glutamic acid and succinic acid --> they must live inside other cells, where these nutrients are provided - Pathogen avoids digestion in phagosome - R. rickettsii does not secrete any toxins - REQUIRE A VECTOR FOR TRANSMISSION BETWEEN HOSTS

Pathogen and virulence factors of Pneumoccocal Pneumonia

- Caused by Streptococcus pneumoniae --> G+, typically diplococci or strepto --> secrete an attachment molecule, which is a poorly defined protein that mediates binding of the bacterium to epithelial cells of the pharynx Virulence factors include adhesins, capsule, pneumolysin - Pneumolysin, a cytotoxin, causes lysis of cells --> Binds to cholesterol in membrane, creates a pore and causes lysis --> Blocks lysosome activity in phagocyte - Unencapsulated variants are avirulent because alveolar macrophages clear them from the lungs - S. pneumoniae inserts into its cell wall a chemical called phosphorylcholine, which by binding to receptors on cells in the lungs stimulates endocytosis of the bacterium

Pathogen and Virulence Factors of Plague

- Caused by Yersinia pestis (G- bacillus) - Various virulence factors --> Adhesins, capsule, antiphagocytic proteins, and type III secretion systems --> Adhesins are molecules that attach pathogens to their target cells, while type III secretion systems inject harmful proteins into the targets - preferentially injects antiphagocytic proteins into dendritic cells, neutrophils, or macrophages, neutralizing their ability to mount an adaptive immune response or to eliminate the bacterium and thus allowing bacteremia - Endotoxin released from dead Yersinia can trigger inflammation, fever, and blood clotting

Pathogen of Blastomycosis

- Caused by dimorphic Blastomyces dermatitidis - Normally grows in soil as a mold, but switches to yeast form at human body temperature --> Yeast form is pathogenic

Zoophilic dermatophytes (2)

- associated with animals - the fungi are transmitted to humans either by close contact with pets or other animals or through contaminated animal products such as wool

Pathogen and virulence factors of Streptococcal Respiratory Diseases

- Caused by group A streptococci (S. pyogenes) Variety of virulence factors: - M proteins: inhibits C3b - Streptokinases: break down blood clots - Streptolysins: lyse RBC, WBC, and platelets - Hyaluronic acid capsule - Pyrogenic toxins: causes release of cytokines that stimulates rash, fever, and shock

Mumps

- Caused by the Mumps virus (-ssRNA) - Humans are the only natural host, infect salivary glands, travels into respiratory system, and becomes systemic. - Acquired by encountering saliva of infected person or contaminated fomites. - Once a very common childhood disease --> Nearly nonexistent in developed countries due to immunization - No specific treatment for mumps, lasts 7-10 days - Infected individuals develop lifelong immunity

Pathogen and Virulence Factors of Lyme Disease

- Caused by the spirochete Borrelia burgdorferi --> has an unusual metabolism in that it does not use iron in its enzymes or its electron transport chains --> uses manganese in place of iron, thereby circumventing one of the body's natural defense mechanisms—the lack of free iron in human tissues and fluids - G- spirochete. - Transmitted via a tick bite, genus Ixodes - Avoids immune detection by changing its outer membrane proteins via genetic rearrangement to emerge as antigenically different variants, making it more difficult for immune cells to recognize the pathogen and clear it from the blood - upon death, releases an active endotoxin (LPS) from its outer membrane

Pathogens and virulence factors of Schistosomiasis

- Caused by three species of Schistosoma - Each species is geographically limited - The freshwater larvae of these worms, called cercariae, can burrow through human skin to enter the blood -- S. mansoni (man-sō′nē) is common in the Caribbean, Venezuela, Brazil, Arabia, and large areas of Africa. -- S. haematobium (hē′mă-tō′bē-ŭm) is found only in Africa and India. -- S. japonicum (jă-pon′i-kŭm) occurs in China, Taiwan, the Philippines, and Japan, although infections in Japan are relatively rare.

Binding of Virus-Infected Cell (picture)

- Cell is virally infected so it will have viral proteins displayed on MHC I - CD8 binds via MHC I

Allergic Contact Dermatitis - Type 4 (5)

- Cell-mediated immune response - Results in an intensely irritating skin rash - Triggered by chemically modified skin proteins that the body regards as foreign - In severe cases, cytotoxic T lymphocytes (Tc cells) destroy so many skin cells that acellular, fluid-filled blisters develop - T cells mediate allergic contact dermatitis - Can be treated with glucocorticoids (corticosteroids)

Diagnosis, Treatment, and Prevention of Chickenpox and Shingles (12)

- Chickenpox diagnosis based on characteristic lesions - It is more difficult to distinguish shingles from other types of skin lesions, though the localization within a band of skin on one side of the body is characteristic - Antibody tests are available to verify the diagnosis of both VZV infections - Treatment of chickenpox based on relief of symptoms (acetaminophen and antihistamines) --> the antiviral drug acyclovir may reduce the severity and duration of chickenpox --> Aspirin should not be given to children or adolescents with symptoms of chickenpox because of the risk of contracting Reye's syndrome—a condition in which the liver and brain cease to function - Treatment of shingles involves management of the symptoms, bed rest, and oral acyclovir --> provides relief from rash but is NOT a cure - difficult to prevent exposure to VZV because viruses are shed from patients before obvious signs appear - Vaccine available against chickenpox --> Since the vaccine provides protection against chickenpox, successfully immunized patients will not develop shingles later in life. --> CDC recommends a single dose of a different, more potent, attenuated vaccine for adults aged 60 or older who had chickenpox as children and two doses of this vaccine for everyone older than 19 who has not had chickenpox or successful immunization in childhood

Diagnosis and Treatment of Dermatophytoses (7)

- Clinical observation is generally sufficient - Potassium hydroxide (KOH) preparations of skin or nail scrapings or hair samples can reveal hyphae and/or conidia (asexual spores), which confirm the diagnosis --> KOH used to see fungi via microscopy - the determination of the specific identity of a dermatophyte requires microscopic examination of a laboratory culture - Limited infections can be treated effectively with topical antifungal agents, but more widespread infections of the scalp or skin, as well as nail infections, must be treated with oral agents --> Terbinafine, administered topically for one to four weeks, is effective in most cases. --> Chronic or stubborn cases are treated with griseofulvin until cured.

Diagnosis, Treatment, and Prevention of inhalation anthrax

- Clinicians can readily identify the large, Gram-positive cells of Bacillus in the sputum of patients, but endospores are seen rarely - Serological, DNA, and biochemical testing confirms the presence of B. anthracis - Penicillin is the preferred drug; however, damage to the lungs and anthrax toxemia can be so severe and rapid that treatment is often ineffectual - obiltoxaximab—a drug composed of monoclonal antibodies directed against an antigen of B. anthracis - An efficacious vaccine is available to select military personnel, researchers, people who work closely with animals, and health care professionals with anthrax patients

Pathogen and Virulence Factors of Botulism

- Clostridium botulinum produces botulism toxin - an anaerobic, endospore-forming, Gram-positive bacillus common in soil and water worldwide - Its endospore, which forms at the end of the cell, survives improper canning of non-acidic foods (pH > 4.5)pH > 4.5 such as meats, eggs, mushrooms, beans, corn, beets, peas, and some cheeses --> Endospores germinate to produce vegetative cells that grow and release the debilitating toxin that causes botulism into the food in the jar or can - Different strains produce one of seven neurotoxins (botulinum toxin A-G) - Results in flaccid (relaxed) paralysis

Pathogen and Virulence Factors of Tetanus

- Clostridium tetani is a small, bacillus, motile, Gram-positive, obligate anaerobe that produces a terminal endospore, giving the cell a distinctive "lollipop" appearance - Found in soil and dust - Produce neurotoxin called tetanospasmin (released when cells die) - Results in tetanic (contracted) paralysis

Anthropophilic dermatophytes (2)

- associated with humans only - transmitted either by close human contact or through the sharing of contaminated fomites

Enzymes of virulent Staphylococcus aureus for Folliculitis (5)

- Coagulase clots blood, which may hide the bacterium from phagocytes. - Hyaluronidase breaks down hyaluronic acid, a major component of the matrix between cells, thus enabling the bacterium to spread between cells throughout the body. - Staphylokinase dissolves blood clots, which also allows staphylococci to spread to new locations. - Lipases, which are present in S. epidermidis as well, digest lipids, including sebum, providing staphylococci with food on the surface of skin, in hair follicles, and in sebaceous glands. - β-Lactamase plays no role in inhibiting the natural defenses of the body, but it does convey resistance to many beta-lactam antimicrobial drugs such as penicillin and cephalosporin—drugs that β-lactamase inactivates.

Microbiome of the Upper Respiratory System

- Colonized by many microorganisms - Fusobacterium, Haemophilus, Lactobacillus, Moraxella, Staphylococcus, Streptococcus, Candida (fungus) - Normal microbiome limit growth of pathogens - Normal microbiome may be opportunistic pathogens

Complement Cascade (4)

- Complement proteins react with one another in an amplifying sequence of chemical reactions in which the product of each reaction becomes an enzyme that catalyzes the next reaction many times over - Complement enzymes cleave other, inactive complement proteins, producing fragments that are active and are designated with lowercase letters. For example, inactive complement protein 3 (C3) is cleaved into active fragments C3a and C3b - Most fragments have specific and important roles in achieving the functions of the complement system. Some combine to form new enzymes; some act to increase vascular permeability, which increases diapedesis; others enhance inflammation; some act as opsonins; and still others are involved as positive chemotactic factors, attracting phagocytes - MAC

Pathogenesis and epidemiology of Toxoplasmosis

- Consumed in undercooked meat containing the parasite. 1 billion people currently infected. - Infects and lives in many cell types - Transmission across the placenta can also occur - Specific mechanism of disease is not yet known

Examples of Normal Microbiota of the Skin (6)

- Corynebacterium (G+; generally nonpathogenic) - Micrococcus (Aerobic, Gram-positive bacteria can tolerate salt concentrations of 5-10%) - Propionibacterium (Gram-positive diphtheroid bacteria; can cause acne, though it also provides protection by competing with pathogenic microbes; reside in hair follicles, where they ferment carbohydrates to form propionic acid, which lowers the pH of the skin, acting as a further defense against additional infection) - Staphylococcus (Aerobic, Gram-positive bacteria can tolerate salt concentrations of 5-10%) - Candida (yeast infections) - Malassezia (lipophilic yeast that digests sebum; can cause disease in immunosuppressed patients)

Treatment and Prevention of Sporotrichosis - wound mycoses (3)

- Cutaneous lesions can be treated successfully with topical applications of saturated potassium iodide for several months. - Itraconazole and amphotericin B are also useful treatments. - Prevention requires wearing gloves, long clothing, and shoes to prevent inoculation.

Pathogen and Virulence Factors of Cytomegalovirus (CMV)

- Cytomegalovirus is an enveloped, double-stranded DNA virus with an icosahedral capsid - typically infects humans early in their lives but remains in a latent state until the immune system is compromised - The major exception is prenatal infection across the placenta from mother to child

Type IV Hypersensitivity (7)

- DELAYED CELL-MEDIATED - Inflammation develops 12 to 24 hours after contact with certain antigens (24-72 to reach max intensity) --> reflects the time it takes for macrophages and T cells to migrate to and divide at the site of the antigen - Results from the actions of antigen, antigen-presenting cells (APCs), and T cells --> NOT FROM THE ACTION OF ANTIBODIES - tuberculin response, allergic contact dermatitis, graft rejection, graft-versus-host disease, donor-recipient matching, tissue typing

Diagnosis, Treatment, and Prevention of Brucellosis

- Daily undulating fever can lead to a diagnosis of brucellosis - Since Brucella is difficult to culture in a laboratory, diagnosis is confirmed by serological tests showing a rising level of antibodies against Brucella - most cases in animals and humans are mild and require no treatment - treat brucellosis with combinations of antibacterial drugs, including doxycycline and rifampin or streptomycin for several weeks - An attenuated vaccine for animals exists, but physicians do not administer it to humans because the vaccine sometimes causes brucellosis - pasteurization of dairy products, immunization of uninfected domesticated animals, and the slaughter of infected ones, the threat of brucellosis for U.S. residents has been reduced

Pathogenesis of Dermatophytoses (6)

- Dermatophytes use keratin as a nutrient source and thus colonize dead layers of skin, nails, and hair - trigger destruction of living cells by the immune system - fungi involved in cutaneous and subcutaneous mycoses commonly grow on decaying matter in the soil - Infection requires introduction of fungal elements into the living, deeper layers of skin --> Thus, exposure is common, but infection is rare. - Most dermatophytoses remain localized to the dermis and hypodermis; infections rarely become systemic.

Pathogenesis of Pertussis (Whooping Cough)

- Destroys ciliated epithelial cells of trachea - Pertussis progresses through four phases --> Incubation, catarrhal (symptoms), paroxysmal, convalescent

Pathogenesis and epidemiology of Klebsiella Pneumonia

- Destruction of alveoli cause bloody sputum - G-, releases endotoxin upon death - Typically a HAI - Immunocompromised individuals at greatest risk for infection because of their poor ability to clear aspirated oral secretions from their respiratory tracts

Diagnosis, Treatment, and Prevention of Tetanus

- Diagnosis based on characteristic muscle contraction; often noted too late to save he patient - Treated with thorough wound cleaning, passive immunotherapy, antimicrobials, active immunization (DTaP: under 11 years old; TDaP: 11-64 years old) - Vaccine available against tetanus

Diagnosis, treatment, and prevention of Viral Meningitis

- Diagnosed by characteristic signs and symptoms in the absence of bacteria in the CSF - No specific treatment exists; rest, hydration, NSAIDs - It is difficult to suppress the spread of enteroviruses because most infected people lack signs or symptoms. Frequent hand antisepsis, avoiding crowded swimming pools, and refraining from bringing contaminated hands near the mouth, nose, or eyes limit the chance of infection

Diagnosis, treatment, and prevention of Variant Creutzfeldt-Jakob Disease (vCJD)

- Diagnosed by characteristic signs and symptoms in the young --> Confused with other forms of dementia in elderly --> lab tests of CNS samples confirm the presence of abnormal prion in the brain - No treatment is available --> interleukins may slow disease progression - Prevented by avoiding prion contaminated meat

Diagnosis, treatment, and prevention of Cryptococcal Meningitis

- Diagnosed by detection of fungal antigen in CSF --> fungal stains can reveal encapsulated yeast in CSF - Treated with combination antifungal drugs (typically IV amphotericin B + oral flucytosine) - Hospitals try to prevent entry of Cryptococcus contaminated air - NO VACCINE

Diagnosis, treatment, and prevention of Pneumoccocal Pneumonia

- Diagnosed by finding diplococci in sputum smear - Penicillin is the drug of choice for treatment - Some strains are now resistant to penicillin --> substitute with vancomycin - Vaccination is method of prevention

Diagnosis, Treatment, and Prevention of Poliomyelitis

- Diagnosed by identification of virus in the throat or feces - No specific treatment exists - Two effective vaccines are available --> OPV: oral, attenuated; not commonly used in industrialized countries because it can revert to a form that can cause paralysis (circulating vaccine-derived poliovirus (cVDPV)) --> IVP: inactivated; cannot revert

Diagnosis, treatment, and prevention of Klebsiella Pneumonia

- Diagnosed by identifying Klebsiella in sputum samples - Primarily supportive, but can be treated with antimicrobials if strain is not resistant --> Emergence of many resistant strains - Cephalosporins are used against Klebsiella - Prevention involves good aseptic technique by health care workers - NO vaccine

Diagnosis, treatment, and prevention of Trachoma

- Diagnosed by identifying bacteria at site of infection --> most specific method of diagnosis involves amplifying the number of chlamydia by inoculating the specimen into a culture of susceptible cells - Treated with antimicrobials and surgery - azithromycin or doxycycline to eliminate genital infections of C. trachomatis in adults - Azithromycin is recommended for treatment of pregnant women - Trachoma strains of C. trachomatis infecting the eyes of newborns are treated with tetracycline or erythromycin cream for 10-14 days - eye infections in adults are treated with oral tetracycline, doxycycline, or erythromycin for three to six weeks

Diagnosis, treatment, and prevention of Schistosomiasis

- Diagnosed by identifying spiny eggs in stool or urine sample --> stool (S. mansoni and S. japonicum) or urine (S. haematobium) - species of blood fluke causing a given infection can be ascertained based on the shape of the egg and the location of its spine - Immunological assays are used to identify antigen when laboratory technicians cannot find eggs in urine or stool samples but infection is suspected - Treated with praziquantel - Prevention requires avoiding potentially contaminated water

Diagnosis, treatment, and prevention of American Trypanosomiasis (Chagas' Disease)

- Diagnosed by microscopic identification of T. cruzi or xenodiagnosis - Early stage can be treated (only 1%), later stages cannot be treated --> Medication can only be obtained from the CDC - Prevention involves avoidance of Triatoma bugs

Diagnosis, Treatment, and Prevention of Leishmaniasis (7)

- Diagnosed by microscopic identification of the protozoa (samples from cutaneous lesions, the spleen, or bone marrow) --> Immunoassays using antibodies to detect antigen confirm the diagnosis and identify the strain --> Genetic analysis using PCR is needed for definitive speciation - Most cases heal without treatment and confer immunity upon the recovered patient - Antimicrobials are needed for severe infections --> Amphotericin B or sodium stibogluconate, an antimicrobial drug that contains the heavy metal antimony - Prevention involves reducing exposure to the reservoir host - NO VACCINE YET

Diagnosis, treatment, and prevention of Infectious Mononucleosis

- Diagnosed by presence of large, lobed B lymphocytes and neutropenia - Treatment focuses on relieving symptoms - Prevention is difficult since occurrence is widespread

Diagnosis, treatment, and prevention of Acne

- Diagnosed by visual examination of the skin - Treated with antimicrobial drugs and drugs that cause exfoliation of dead skin cells - topical benzoyl peroxide, which causes exfoliation of dead skin cells, kills Cutibacterium, reduces the amount of lipid on the skin's surface, and has beneficial oxidizing effects - Accutane is used to treat severe acne; Retinoic acid (Accutane), a derivative of vitamin A, inhibits the formation of sebum, reducing the amount available for bacterial metabolism --> Has severe side effects; Because Accutane can cause intestinal bleeding and birth defects, it is prescribed only for severe cases of acne and never for women who are or may become pregnant. - Long-term antimicrobial use can destroy susceptible normal bacteria, making the individual more vulnerable to opportunistic fungi and to bacteria that are resistant to antimicrobial drugs - Ultraviolet light is also used to destroy bacteria --> two 15-minute exposures a week for a period of four weeks produced a 60% reduction in acne in 80% of patients for up to eight months

Diagnosis, treatment, and prevention of Legionnaires' Disease

- Diagnosed with fluorescent antibody staining or serology - prescribe intravenous doxycycline, tigecycline, azithromycin, or a quinolone for treating severe cases of Legionnaires' disease - Quinolones or azithromicin are the preferred treatment - Control by reducing bacterial presence in water --> not feasible, because chlorination and heating are only moderately successful against the microorganism. However, the bacterium is not highly virulent, so merely reducing its number is typically a successful control measure

Diagnosis, treatment, and prevention of Peptic Ulcers

- Diagnosis based on X-ray exam to identify ulcers and presence of H. pylori in clinical specimens - Treat with antimicrobials and drugs that inhibit stomach acid - Prevent by avoidance of fecal-oral transmission

4 conditions possible from polio

- asymptomatic infections - minor polio - nonparalytic polio - paralytic polio

Diagnosis, treatment, and prevention of African Viral Hemorrhagic Fevers

- Diagnosis based on characteristic symptoms and presence of virus in the blood --> demonstration of the viruses in the blood via ELISA or PCR - Treatment involves fluid and electrolyte replacement --> Experimental: give passive immunotherapy from individuals who have fully recovered - no effective antiviral drugs to treat filovirus hemorrhagic fevers - Vaccines are being studied for their effectiveness in humans - Fruit bats and monkeys/apes are thought to be the natural reservoir, so avoidance may aide in prevention.

Diagnosis, treatment, and prevention of Blastomycosis

- Diagnosis based on fungus identification in clinical samples - Treated with amphotericin B (IV) for 10 weeks, or oral itraconazole for 6 months - Relapse common in AIDS patients

Diagnosis, treatment, and prevention of Cholera

- Diagnosis based on presence of "rice-water stool" --> Watery, colorless, odorless, and flecked with mucus (which looks like rice) - Treat with supportive care and administration of doxycycline --> Reduces duration of diarrhea and volume of stool - Available vaccine provides only short-lived immunity - Proper hygiene is an important preventive measure

Diagnosis, treatment, and prevention of Diptheria

- Diagnosis based on presence of a pseudomembrane - Treat with antitoxin and antibiotics --> acrolides (e.g., erythromycin) for patients older than six months and intramuscular penicillin for younger patients to treat diphtheria - Immunization is an effective prevention (DTaP) --> Immunization involves the DTaP (diphtheria, tetanus, acellular pertussis) vaccine --> After vaccination, 20 cases from 1992 to 2012

Diagnosis, treatment, and prevention of Dengue Fever and Dengue Hemorrhagic Fever

- Diagnosis based on signs and symptoms in people who have traveled to endemic regions - No specific treatment available - Prevention requires control of mosquitoes

Diagnosis, Treatment, and Prevention of Measles (6)

- Diagnosis based on signs of measles (Koplik's spots) - serological testing can confirm the presence of measles antigen in respiratory and blood specimens - No treatment is available --> Supportive therapies such as administration of vitamin A, antibodies against measles, and ribavirin (nucleoside analog) that show mixed results - MMR vaccine protects against measles --> Research has shown that measles elimination requires achieving and sustaining a two-dose immunization coverage of at least 95% of a population

Diagnosis, treatment, and prevention of Bacterial Meningitis

- Diagnosis based on symptoms and culturing of bacteria from CSF - serological tests can demonstrate the presence of antibodies against N. meningitidis, though strain B of this species is relatively nonimmunogenic and therefore often not revealed by such tests - Treated with intravenous antimicrobial drugs --> vancomycin plus ceftriaxone, cefotaxime, meropenem, or ampicillin, depending on the age and health of the patient and the bacterium causing the meningitis - Vaccines available for S. pneumoniae, H. influenzaetype b, and N. meningitidis - health care providers prevent the spread of group B streptococcal infection to babies by treating infected pregnant mothers with penicillin or ampicillin, or with vancomycin for patients with penicillin allergy

Diagnosis, Treatment, and Prevention of Hansen's

- Diagnosis based on the signs and symptoms --> a loss of sensation in skin lesions in the case of tuberculoid leprosy, and disfigurement in the case of lepromatous leprosy --> Confirmed by presence of acid-fast bacilli in samples - Treated with multiple antimicrobials --> Leprosy bacteria quickly develop resistance to single antimicrobial agents --> treatment is a minimum 2 yrs but can be lifelong --> Ex. rifampin, clofazimine, and dapsone - tuberculosis BCG vaccine provides some protection --> presumably because the bacteria of leprosy and tuberculosis are related and share antigens

Diagnosis, treatment, and prevention of Rabies

- Diagnosis by unique neurological symptoms --> Tests for antibodies in the blood confirm --> Once neurological symptoms present -> fatal - Postmortem detection of Negri bodies in the brain (aggregates of the virus) (collection of fragments of virons within the cytoplasm of neurons) - Treated with human rabies immunoglobulin, vaccine injections, and cleansing infection site --> Effective if treated within first 10 days --> 4 vaccine injections: day 1, 3, 7, and 14 - Prevented by controlling rabies in domestic animals

Diagnosis, Treatment, and Prevention of Pseudomonas infections (8)

- Diagnosis can be difficult --> because Pseudomonas presence in a culture may represent contamination acquired during collection, transport, or inoculation --> Pyocyanin discoloration indicates massive infection - Difficult to treat due to multidrug resistance of P. aeruginosa --> Pseudomonas has been reported to live in solutions of some antibacterial drugs and disinfectants - treat infections with combinations of aminoglycoside, beta-lactam, and fluoroquinolone antimicrobials that have first proven efficacious against a particular isolate in a susceptibility test - P. aeruginosa is widespread, but infections typically don't occur in healthy individuals --> rarely causes diseases because it does not normally penetrate the skin and mucous membranes, nor does it ultimately evade the body's other defenses

Diagnosis, Treatment, and Prevention of HIV (9)

- Diagnosis involves detecting antibodies against HIV (ELISA and Immunoblot) --> Can indicate infection with HIV but not presence of AIDS --> positive test for antibodies does not mean that HIV is currently present or that the patient has or will develop AIDS; merely indicates that the patient has been exposed to HIV. - Doctors use a PCR test for HIV RNA to make a definitive diagnosis - Small percentage of infected individuals are long-term nonprogressors --> Do not develop AIDS --> Possible reasons: defective virions, poor binding of HIV to cells, or well-developed immune systems - Most individuals develop antibodies within six months of infection, though some remain without detectable antibodies for up to three years - Diseases associated with AIDS are treated individually

Diagnosis, treatment, and prevention of Tularemia

- Diagnosis is difficult and requires serological confirmation - Culturing is not recommended because the organism is extremely virulent and easily contractible in the laboratory - Treated with antimicrobials - F. tularensis produces β−lactamase, so penicillins and cephalosporins are ineffective, but other antimicrobial drugs have been used successfully. Currently, streptomycin or gentamicin is commonly used - Vaccine available for people at risk for exposure --> not entirely effective, it can lessen the severity of the disease

5 Vaccine Types

- attenuated (modified live) vaccines - inactivated (or killed) vaccines - toxoid vaccines - combination vaccines - recombinant gene vaccines

Diagnosis, Treatment, and Prevention of bacterial intoxications (toxifications) (food poisoning)

- Diagnosis is generally based on signs, symptoms, and patient history - Tests may be done on samples from vomit, blood, stool, or any leftover food deemed suspicious. - Stool cultures positive for S. aureus are indicative of staphylococcal food poisoning, but other examinations are often inconclusive - Replacement of fluids and electrolytes is the preferred treatment and can be self-administered - Good hygiene and proper food handling reduce incidence.

Diagnosis, treatment, and prevention of Salmonellosis and Typhoid Fever

- Diagnosis made by finding Salmonella in stool - Salmonellosis is usually self-limiting (~7 days) - Typhoid fever can be treated with antimicrobial drugs - Prevented with proper hygiene

Diagnosis, treatment, and prevention of Malaria

- Diagnosis made by identifying Plasmodium in blood - Treatment varies by species and disease severity --> Some Plasmodium strains resistant to antimalarial drugs - Prevention requires control of mosquitoes and administration of a combination of antimalarials if traveling

Diagnosis, treatment, and prevention of Scabies (6)

- Diagnosis made by observing mites, eggs, or fecal matter in skin samples or the characteristic burrows --> However, since there are typically fewer than 10 mites on the entire body of a patient, clinicians may miss them - Treated with mite-killing lotions and cleaning of contaminated items; lotion absorbed into blood --> frequent use or application on infants or pregnant or lactating women is ill advised - Prevented only by good personal hygiene - NO IMMUNITY TO SCABIES CAN DEVELOP

Diagnosis, Treatment, and Prevention of Herpes infections (8)

- Diagnosis made by presence of characteristic lesions - Microscopic examination of infected tissue reveals syncytia - Immunoassay reveals presence of viral antigens - Chemotherapeutic drugs help control the disease but do not cure it - Herpes infections are among the few viral diseases that can be controlled with nucleoside analogs such as valacylovir, acyclovir, or peniciclovir --> Topical applications of the drug limit the duration of the lesions and reduce viral shedding, though the drug does not cure the diseases or free nerve cells of viral infections. - Health care workers can reduce their exposure to infection by wearing latex or nitrile gloves - Since a whitlow is a potential source of infection, symptomatic personnel should not work with patients, especially newborns, until the whitlow has healed

Diagnosis, Treatment, and Prevention of Coccidioidomycosis

- Diagnosis of coccidioidomycosis is based on the identification of spherules in clinical specimens; diagnosis is confirmed by injecting antigen beneath the skin and observing an inflammatory response - Intravenous amphotericin B is the drug of choice; unfortunately, it is one of the more toxic antifungal agents to humans - In AIDS patients, maintenance therapy with other antifungal drugs, such as itraconazole or fluconazole, is recommended to prevent relapse or reinfection - wear masks in endemic areas

Diagnosis, Treatment, and Prevention of Arboviruses

- Diagnosis of human arboviral encephalitis is based upon observation of signs and symptoms followed by a positive laboratory test for antibodies against specific arboviruses in the CSF - A commonly used laboratory test measures the concentration of IgM, the antibody class produced early in an infection - The test is positive in most infected people within eight days of onset of symptoms. - As with viral meningitis, treatment for arboviral encephalitis is supportive: possible hospitalization, administration of intravenous fluids, respiratory support (ventilator), prevention of secondary infections - Human disease is prevented by limiting contact with mosquitoes—through the use of netting and insect repellent containing DEET - vets can administer vaccines to horses; no human vaccines yet exist

Diagnosis, Treatment, and Prevention of Botulism

- Diagnosis: - symptoms, culture from the contaminated food, feces or from wound confirms - mouse bioassay Four approaches to treatment: 1. Maintain open and functional airways 2. Wash intestinal tract to remove Clostridium 3. Administer anti-botulinum antibody (BIG-IV) --> neutralizes the neurotoxins in the blood before they can bind to neurons and shortens the length of the disease 4. Treat with antimicrobial drugs --> chloramphenicol (preferential) or penicillin to kill the bacterium in wound botulism --> not recommended for treating infant botulism, because the treatment increases toxin release, worsening the disease --> not effective in treating foodborne botulism, because foodborne botulism results from ingestion of the toxin, not of the bacteria themselves - Prevented by destroying endospores in contaminated food - preventing endospores from germinating through use of refrigeration or establishment of an acidic environment - destroying the toxin with heat—food must be heated to at least 80°C for 20 minutes or more - C. botulinum produces gas at it grows, so a swollen can of food may indicate contamination. - Infant botulism is often associated with the consumption of honey, particularly unpasteurized honey (NO HONEY FOR BABIES)

ELISA advantages (7)

- ELISAs are sensitive, able to detect very small amounts of antibody (or antigen). - Unlike some diffusion and fluorescent tests, ELISA can quantify amounts of antigen or antibody. Knowing the amount of antigen or antibody in a patient's serum can provide information concerning the course of an infection or the effectiveness of a treatment. - ELISAs are easy to perform. - ELISAs are relatively inexpensive. - ELISAs can simultaneously test many samples quickly at once. - ELISAs can be read easily, either by direct observation or by machine, lending themselves to efficient automation. - Plates coated with antigen and gelatin can be stored for testing whenever they are needed.

African Viral Hemorrhagic Fevers - Types

- Ebola hemorrhagic fever (often fatal disease beginning with flu-like symptoms and progressing to severe internal hemorrhaging; caused by Ebolavirus) - Lassa hemorrhagic fever ("Lassa fever"; disease caused by Lassa virus, a single-stranded RNA virus in the family Arenaviridae) - Marburg hemorrhagic fever (often fatal disease beginning with flu-like symptoms and progressing to severe internal hemorrhaging; caused by Marburgvirus)

Pathogens and Virulence Factors of Ehrlichiosis and anaplasmosis

- Ehrlichia chaffeensis causes ehrlichiosis - Anaplasma phagocytophilum, causes anaplasmosis - Both bacteria are rickettsias, which are Gram-negative, highly pleomorphic, obligate intracellular parasites of eukaryotic cells - The bacteria trigger their own endocytosis (internalization by a cell) by white blood cells—monocytes in the case of Ehrlichia and neutrophils in the case of Anaplasma—and then live inside phagosomes - bacteria prevent fusion of lysosomes in the phagocyte with their phagosome homes by an unknown mechanism

amebiasis Pathogen, Virulence Factors, and Pathogenesis

- Entamoeba histolytica - motile trophozoite - develops into an infective, resistant, chitin-shelled cyst. Virulent strains of Entamoeba produce adhesion proteins, proteases, proteins that create ion channels in host membranes, and other small proteins that appear to have toxic effects on cells and facilitate invasion. - Avirulent strains of Entamoeba do not produce these four types of proteins and so remain in the lumen of the intestine - Infection begins with ingestion of thick-shelled cysts, which pass successfully through the acid of the stomach and excyst in the small intestine to release trophozoites - These migrate to the large intestine and multiply by binary fission, producing any signs and symptoms in one to four weeks. - Trophozoites use pseudopodia to attach to specific receptors on the intestinal lining, where they feed. - Both trophozoites and cysts are shed into the environment in feces, but trophozoites die - Trophozoites in the lumen of the intestine do little damage and typically produce no symptoms, but when trophozoites invade the peritoneal cavity and bloodstream, amebic dysentery or invasive extraintestinal amebiasis occur. - The difference in severity is due to the production of differing virulence factors by various strains.

Pathogenesis and epidemiology of Blastomycosis

- Enters body through inhalation of dust carrying fungal spores, spores germinate to form yeast. - Incidence of human infection is increasing - If immunocompetent, minor lesions and pulmonary blastomycosis will resolve

fomivirsen

- Eye doctors inject fomivirsen into the eye to inhibit the replication of CMV in retinal cells - Fomivirsen, which is the first antisense RNA drug, is RNA complementary to CMV mRNA - It binds to CMV mRNA and stops translation of two proteins critical for CMV replication - This stops the replication and spread of CMV but does not cure the disease

Trichomoniasis

- Females have vaginal discharge and vaginal irritation - Males are typically asymptomatic - Caused by Trichomonas vaginalis --> flagellated protozoan parasites of animals and humans --> 5 anterior flagella and an undulating membrane --> reproduces at pH 5 to pH 6. Normal lactobacilli keep the pH of the vagina at 4.0 to 4.5; thus, the vaginal microbiome helps keep Trichomonas in check - Only lives in humans: vagina, urethra, prostate - Binds to epithelial cells and causes inflammation - Transmission primarily via sexual intercourse, cannot live long outside the body - Increases risk of infection by HIV and other STDs - Diagnose by presence of Trichomonas in clinical samples - Treat with a single dose of oral metronidazole or tinidazole - Prevent by avoiding sexual intercourse with infected persons

Hantavirus Pulmonary Syndrome (HPS)

- Fever, fatigue, muscle aches (thigh, hip, back). In 4-10 days, symptoms progress to cough, shock, and labored breathing as lungs rapidly fill with fluid. - Elevated leukocyte count and drop in platelet count

Epidemiology of AIDS (PROF NOTES) (5)

- First recognized in young male homosexuals in the U.S. - Now found worldwide - HIV in blood, semen, saliva, vaginal secretions, and breast milk concentrated can cause infection --> Blood and semen are more infective than other secretions ----> Infected blood contains 1000 to 100,000 virions per milliliter, while semen has 10 to 50 virions per milliliter. --> Infected fluid must be injected or encounter a tear or lesion in the skin or mucous membranes

Blastomycosis

- Flulike symptoms - Systemic infections (~60%) can produce PAINLESS lesions on the face and upper body. 30% will form purulent (pus-filled) lesions on various organs.

Bacterial Urinary Tract Infections

- Frequent, urgent, painful urination (dysuria) - Urine may be cloudy with foul odor - Enteric bacteria are the most common cause - Escherichia coli causes most cases - Virulence factors include flagella and attachment fimbriae - Often self-inoculate fecal bacteria into the urethra - More common in females - Diagnosis based on urinalysis - Many cases resolve without treatment - Some require treatment with antimicrobial drugs - Prevent by limiting contamination by fecal microbes

Pathogen and virulence factors of Rabies

- Gram-negative, single-stranded RNA (-ssRNA) virus in the genus Lyssavirus, family Rhabdoviridae - P protein inhibits interferon release - helical capsids supercoiled into cylinders, which give them a striated appearance, and are surrounded by bullet-shaped envelopes - Glycoprotein spikes on the surface of the envelope serve as attachment proteins.

Streptococcus pyogenes (group A Streptococcus) (FROM BOOK)

- Gram-positive coccus whose offspring remain attached in chains following cell division - causes 20% of impetigo cases, GAS also causes most cases of cellulitis and is the cause of erysipelas - Virulence Factors: M protein, hyaluronic acid capsule, Pyrogenic toxins

Listeria monocytogenes - pathogen of bacterial meningitis

- Gram-positive, non-endospore-forming coccobacillus - enters the body in contaminated food or drink - rarely pathogenic in healthy adults - infection in pregnant women, fetuses, newborns, the elderly, and immunocompromised patients can result in meningitis

Viral Hepatitis Pathogen and Pathogenesis; Part 2

- HAV: mild, AKA infectious hepatitis --> Clears up in 99% of cases - HBV: occasionally severe (10%), AKA serum hepatitis --> Chronic infection (exocytosis), all body fluids infected - HCV: usually subclinical, AKA chronic hepatitis --> No genetic proofreading, constant mutations and multiple strains within infected person; chronic in 70% - HDV: coinfection causes severe acute disease --> Lacks capsid genes, relies on HBV capsid proteins. Must be within coinfected cell; chronic. - HEV: mild --> Infects many animals, only human-to-human

Epidemiology of Oral Herpes

- HHV-1 accounts for 90% of all cold sores - HHV-2, the normal cause of genital herpes, causes the other 10% of cold sores - HHV-1 is transmitted by close contact with infected individuals who have active lesions - HHV-2 spreads through oral sex with infected partners. - Primary HHV-1 infections typically occur via casual contact during childhood and usually produce no signs or symptoms --> HHV-1 has asymptomatically infected about 80% of children by age two

Pathogenesis of Lyme Disease

- Hard ticks of the deer tick genus Ixodes are the vectors of Lyme disease - lives for two years, during which it passes through three stages of development: a six-legged larva, an eight-legged nymph, and an eight-legged adult - Once during each stage, it attaches to a vertebrate host for a single blood meal. After each of its three feedings, the tick drops off its host and lives in leaf litter or on brush

Pathogenesis of Ehrlichiosis and anaplasmosis

- Hard-shelled ticks, including the Lone star tick (Ambylomma), the deer tick (Ixodes), and the dog tick (Dermacentor), vector the bacterial agents of ehrlichiosis and anaplasmosis into humans - Once inside blood cells, the bacteria grow and reproduce within phagosomes passing through three developmental stages: an elementary body, an initial body, and a morula - Release of the bacteria from a morula and into the blood makes them available to feeding ticks, which become infected and pass the bacteria on to a new host

debridement (2)

- Health care workers must remove the burn's crust in a medical procedure termed debridement so that antimicrobial drugs can be effective - the removal of dirt, foreign objects, damaged tissue, and cellular debris from a wound to prevent infection and to promote healing

Pathogenesis of Herpes Infections (11)

- Herpesviruses are most often spread between mucous membranes of the mouth or genitals - viruses may remain inactive inside infected cells, often for years - Inactive viruses may reactivate as a result of aging, chemotherapy, immunosuppression, or physical and emotional stress, causing a recurrence of the manifestations of their diseases - attach to host cells through the fusion of their envelope with the cells' cytoplasmic membranes - After the viral genome is replicated and assembled in a cell's nucleus, a herpesvirus acquires an envelope from the nuclear membrane and exits the cell via exocytosis or cell lysis - Active lesions are the usual source of infection, though asymptomatic carriers can shed HHV-2 genitally - After entering the body through cracks or cuts in mucous membranes, viruses reproduce in epithelial cells near the site of infection and produce inflammation and cell death, resulting in painful, localized lesions on the skin - By causing infected cells to fuse with uninfected neighboring cells, both HHV-1 and HHV-2 can form a structure called a syncytium, which is a multinucleate cytoplasmic mass, allowing the viruses to spread and in the process avoid the host's humoral immune system. - Painful lesions caused by inflammation and cell death - Cause fusion of infected cells to form syncytia - Virus becomes latent in neurons.

Tapeworm Infestations Epidemiology

- High incidence --> Regions of inadequate sewage treatment --> Regions where humans live in close contact with livestock

Epidemiology of Pertussis (Whooping Cough)

- Highly contagious, life threatening cases occur in children under 5 years old - Bacteria spread through the air in airborne droplets - Bacteria do not survive long outside the body

Pathogen of Histoplasmosis

- Histoplasma capsulatum - dimorphic ascomycete that is found in moist soils containing high levels of nitrogen such as from the droppings of bats and birds, especially chickens, starlings, and blackbirds - becomes a pathogenic yeast at human body temperature (37°C) --> produces several proteins that prevent full activation of macrophages and abrogate host defenses such as production of free radicals and antimicrobial peptides

Epidemiology of Hantavirus Pulmonary Syndrome (HPS)

- Human disease more likely as mouse population increases - Person-to-person contact does not occur

Pathogen and Virulence Factors of Infectious Mononucleosis

- Human gammaherpesvirus 4 (HHV-4) --> dsDNA --> AKA "Epstein-Barr virus" (EBV) - HHV-4 establishes latent infection in B cells --> Suppresses apoptosis of infected cells - HHV-4 implicated in number of other diseases - Disease caused by HHV-4 depends on state of cellular immunity

Pathogen and Pathogenesis of Oral Herpes

- Human herpesvirus 1 (HHV-1; previously called herpes simplex virus 1) causes most cases of oral herpes - HHV-2, which usually infests the genitalia, can also infect the oral cavity - After entering the body through cracks or cuts in mucous membranes, herpesviruses reproduce in epithelial cells near the site of infection, triggering inflammation and cell death and resulting in painful, localized lesions on the skin 2-12 days after infection - Herpes virions cause infected cells to fuse with uninfected neighboring cells to form a structure called a syncytium; in this way, herpes viruses spread from cell to cell, avoiding the host's immune system - Lesions usually last two to three weeks - HHV-1 and HHV-2 can eventually establish latent infections in the trigeminal nerve ganglion by entering sensory nerve cells and being carried by cytoplasmic flow to the ganglion - Latent viruses may reactivate later in life when the immune system is suppressed by emotional stress, fever, trauma, sunlight, menstruation, or disease - Reactivated viruses travel down the nerve to produce recurrent lesions as often as every two weeks - Reactivated viruses travel down the nerve to produce recurrent lesions as often as every two weeks. Recurrent lesions are rarely as severe as the initial lesions because of immunological memory - Recurrent lesions are rarely as severe as the initial lesions because of immunological memory.

Pathogenesis and Epidemiology of Brucellosis

- Humans become infected either by consuming unpasteurized contaminated dairy products or through contact with animal blood, urine, or placentas - bacterium enters the body through breaks in mucous membranes of the digestive and respiratory tracts - travels inside phagocytic cells to organs of the body, including lymph nodes, spleen, bone marrow, liver, and heart - Arthritis, splenomegaly (enlarged spleen), enlarged testes, endocarditis, meningitis, and encephalitis may result.

Type III Hypersensitivity (8) (PROF NOTES)

- IMMUNE COMPLEX-MEDIATED - Caused by formation of immune complexes that trigger the release of inflammatory chemicals - Can cause localized reactions or systemic reactions simultaneously --> Hypersensitivity pneumonitis --> Glomerulonephritis - Can cause systemic reactions --> Systemic lupus erythematosus --> Rheumatoid arthritis

5 Classes of Antibodies (picture)

- IgM: first antibody produced - IgG: most common and longest-lasting antibody - IgA: associated with body secretions (mammary glands, lacrimal glands, mucous membranes) - IgE: involved in response to parasitic infections and allergies in developed countries - IgD: exact function unknown

Bacterial Pneumonias

- Lung inflammation accompanied by fluid: filled alveoli and bronchioles - Described by affected region or organism causing the disease - Bacterial pneumonias are the most serious and the most frequent in adults

Rheumatoid Arthritis (RA) - systemic Type 3 (10)

- Immune complexes deposited in the joint --> B cells secrete IgM that binds to certain IgG molecules --> IgM-IgG complexes are deposited in the joints, where they activate complement and mast cells, which release inflammatory chemicals --> The joints begin to break down and become distorted --> causes the tissues to swell, thicken, and proliferate into the joint, resulting in severe pain --> altered tissue extends into the joint, the inflammation further erodes and destroys joint cartilage and the neighboring bony structure until the joints begin to break down and fuse - Trigger not well understood --> only occurs in humans so research is hindered - Treated with anti-inflammatory drugs - course of rheumatoid arthritis is often intermittent

Pathogenesis of Measles (7)

- Immune response to infected cells causes most symptoms - Disease can be fatal in children --> Most patients recover within two to three weeks, though 1-5% of infected children die - Measles virus infects cells of the respiratory tract before spreading via lymph and blood throughout the body to infect the conjunctiva, urinary tract, small blood vessels, lymphatics, central nervous system, and skin - Cytotoxic T cells kill infected cells, causing most of the symptoms - secondary infections by bacteria such as Staphylococcus or Streptococcus can increase the seriousness of measles - Patients with compromised cellular immunity, such as AIDS patients, can have continued measles infection, resulting in death

Erysipelas (9)

- Impetigo spreading to lymph nodes, accompanied by pain and inflammation - caused by infection with Group A Streptococcus (GAS) - Most caused by Streptococcus pyogenes (PROFESSOR NOTES) --> GAS AND S. PYOGENES ARE THE SAME THING - red rash in infected region - area nearly always occurs on only one side of the body with a distinct border (margins) - lack pus - Swollen local lymph nodes, pain, fever, chills, and leukocytosis (abnormally large number of leukocytes in the blood) - can be fatal is untreated --> The very young, very old, and immunocompromised are more likely to die

Exogenous Antigens (2)

- Include toxins and other components of microbial cell walls, membranes, flagella, and pili - originate from microbes located outside the body's cells

Examples of Antigens (5)

- Include various bacterial components (cell walls, capsules, pili, flagella) - as well as proteins of viruses, fungi, and protozoa - Many toxins and some nucleic acid molecules - Food allergens - dust contains mite feces, pollen grains, dander (flakes of skin), and more antigenic and allergenic particles

What is the purpose of vasodilation in inflammation? (3)

- Increased blood flow due to vasodilation delivers more neutrophils and monocytes to the site of infection - leukocytes then adhere to receptors lining the vessels (margination) - diapedesis occurs within an hour of infection

Pathogenesis and epidemiology of Pneumoccocal Pneumonia

- Infection occurs by inhalation of bacteria - Bacterial replication causes cell death in lungs --> they damage the lining of the alveoli, allowing erythrocytes, leukocytes, and blood plasma to enter the lung. This fluid fills the alveoli, reducing the lung's ability to transfer oxygen to the blood and causing the pneumonia - Pneumococcal IgA protease destroys host secretory IgA - Typically occurs in children <5 and adults >65 - Phosphorylcholine triggers endocytosis by lung cells, the capsule protects the bacterium, and thereby pneumococci live in and eventually kill lung cells - From their intracellular "hiding place," S. pneumoniae bacteria can pass into the blood and brain to cause bacteremia and meningitis

Pathogenesis and epidemiology of Cryptococcal Meningitis

- Infections follows inhalation of spores or dried yeast cells - Many cases occur in terminal AIDS patients and in transplant recipients

Viral Hepatitis Diagnosis, treatment, and prevention

- Initial diagnosis made by observation of jaundice, enlarged liver, or fluid in the abdomen - Serological testing can identify viral antigens - HBV diagnosed by viral proteins in body fluids - HCV treatment only needed for chronic infections --> Harvoni, Olysio, Sovaldi, Viekira Pak cure infection - IFN-α and nucleotide analogs help reduce levels of virus - Supportive care for symptoms - Prevent with good hygiene, protected sex or abstinence - Vaccines are available against HAV and HBV --> HAV: 10 years; HBV: lifetime

Pertussis (Whooping Cough)

- Initially coldlike, then characteristic cough develops - Oxygen exchange in the lungs may be so severely limited that cyanosis develops (the patient turns blue), and death results - characteristic sign of whooping cough occurs during the two to four weeks of the paroxysmal phase: to clear mucus from the lungs, the patient coughs two or three times without inhalation, followed by the characteristic "whoop" of inhalation through a congested trachea --> Each day a patient may experience 40-50 of these coughing spells, which often end with vomiting and exhaustion. Coughing may be so brutal that blood vessels in the eyes burst

Pathogenesis and epidemiology of Scabies (4)

- Itching blisters occur where female mites lay eggs - Symptoms may take four to six weeks to develop as type IV (delayed) hypersensitivity plays a role in a patient's reaction - Mites transmitted via prolonged body contact; fomites; sexual transmission - Epidemics occur in crowded conditions

Tuberculosis Epidemiology

- Killed more people that any other disease. 1/3 of world population is infected. - Immunocompromised individuals are most at risk - Tuberculosis is leading killer of HIV+ individuals

Pathogenesis of Legionnaires' Disease

- L. pneumophila is an intracellular parasite that kills human cells --> Causes tissue damage and inflammation - For unknown reasons, Legionella rarely spreads outside the lungs

Origin of HIV (5)

- Likely arose from mutation of the simian immunodeficiency virus (SIV) --> the nucleotide sequence of SIV is similar to those of the two strains of HIV - Estimated to have emerged in the human population around 1930 --> Based on mutation rates and the rate of antigenic change in HIV - historical relationships between the two types of HIV and SIV are not clear

Pathogenesis of Hansen's

- M. leprae grows best in cooler regions of the body --> Affinity to grow inside of neurons --> preferred sites of reproduction are neuroglia of peripheral nerve endings, cells of the mucous membrane of the nose, and skin cells in the fingers, toes, lips, and earlobes --> Mycobacterium is the only known bacterial pathogen of peripheral nerves - M. leprae can live inside infected cells for 10-30+ years - Cellular immune response eventually attacks infected cells --> May destroy nerves and other tissues

Pathogenesis of Tuberculosis

- M. tuberculosis remains viable for long time in aerosol drops - Three types of tuberculosis --> Primary tuberculosis and secondary tuberculosis --> Disseminated tuberculosis

Why is Donor-Recipient Matching so difficult? (4)

- MHC compatibility is hard to achieve - the very high degree of MHC variability ensures that unrelated individuals differ widely in their MHCs - the more closely donor and recipient are related, the smaller their MHC difference - it's preferable that grafts be donated by a parent or sibling possessing MHC antigens similar to those of the recipient

Plasma Cells (8)

- Majority of cells produced during B cell proliferation - Only secrete antibody molecules complementary to the specific antigen - Short-lived cells that die within a few days of activation - Their antibodies (for weeks) and progeny (for years) can persist - as the plasma cell clones replicate, each one slightly modifies its antigen-binding-site genes such that each descendant secretes antibodies with slightly different variable regions - Each plasma cell produces different classes of antibodies - They begin by secreting IgM and then, through class switching, secrete IgG or IgA or IgE - Class switching is primarily controlled by Th cells and is irreversible

Gonorrhea ("The Clap" from clapoir)

- Men experience painful urination and a purulent discharge (pus) - Women are often asymptomatic (50-80%) --> Pelvic inflammatory disease develops in 25% - Caused by Neisseria gonorrhoeae --> G- diplococci - Virulence factors: fimbriae, capsule, and cell wall antigen lipooligosaccharide (contains lipid A) - The cocci also protect themselves from the immune system by secreting a protease enzyme that breaks down secretory IgA in mucus - Survives phagocytosis and spreads via neutrophils - Bacteria attach to epithelial cells of the mucous membranes. - Causes inflammation, damage, infertility, and death - Gonorrhea occurs only in humans - Risk increases with frequency of sexual encounters - Morphological detection in pus or use of genetic probes to diagnose asymptomatic infection - Dual therapy: ceftriaxone and azithromycin --> Resistant to penicillin, tetracycline, erythromycin, and more.

Diagnosis of Sporotrichosis - wound mycoses (3)

- Microscopic observation of pus or biopsy tissue stained with silver can reveal budding yeast forms in severe infections --> often the fungus is present at a low density, making direct examination of clinical samples a difficult method of diagnosis - The patient's history and clinical signs, plus the observation of the dimorphic nature of S. schenckii in laboratory culture, are considered diagnostic for sporotrichosis.

Pathogen and virulence factors of Necrotizing Fasciitis (8)

- Most cases caused by S. pyogenes - Various exoenzymes facilitate invasion of tissues --> Streptokinase (breaks clots), hyaluronidase (breaks down hyaluronic acid between cells), deoxyribonucleases (break down DNA released from damaged host cells) - Streptococcal Protein M allows bacterium to attach to nasopharyngeal cells and resist phagocytosis - Pyrogenic toxin: superantigen - Streptolysin S toxin can kill many types of human cells, including neutrophils and erythrocytes - Exotoxin A triggers an overactive immune response that further damages healthy tissue - tissue can be destroyed at a rate of several centimeters an hour

Pathogen of Folliculitis (5)

- Most commonly caused by Staphylococcus --> Facultatively anaerobic, G+ cocci --> Tolerant of salt and desiccation - found on human skin as well as in the upper respiratory, gastrointestinal, urinary, and genital tracts - Ex. Staphylococcus epidermidis (major member of the microbiome, accounting for up to 90% of bacteria on the skin) & Staphylococcus aureus (often grows in nasal passages, produces a variety of disease conditions and symptoms)

Signs and Symptoms of Arboviruses

- Most mosquito-borne arboviruses cause only mild, coldlike symptoms in humans within three to seven days of infection - Occasionally arboviruses in the blood cross the blood-brain barrier to cause arboviral encephalitis --> characterized by signs and symptoms similar to those of meningitis: high fever, weakness, nausea, vomiting, abrupt headache, and changes in mental state such as confusion, disorientation, and coma --> Some patients report body aches and develop a skin rash. Neurological effects may be permanent - Humans are not the only victims. Arboviruses also attack birds, horses, chimpanzees, cats, dogs, chipmunks, and even alligators

Pathogens and Virulence Factors of Hansen's Disease

- Mycobacterium lepraeis the causative agent --> Acid fast bacillus --> high G+C non-endospore-forming, Gram-positive bacilli with cell walls containing a large amount of mycolic acid

Pathogen and Virulence Factors of Primary Atypical (Mycoplasmal) Pneumonia

- Mycoplasma pneumoniae is a strictly aerobic, encapsulated mycoplasma - lack cell walls, allowing them to have a variety of shapes—they are pleomorphic - have lipids in their cytoplasmic membranes called sterols, a feature lacking in other prokaryotes - the smallest free-living microbes; can grow and reproduce independently of other cells - thought to be viruses but they reproduce by binary fission - Despite being Gram-positive, they appear pink when Gram stained, because they lack cell walls - M. pneumoniae is one of the few mycoplasmas that causes human disease --> adhesive protein that attaches specifically to receptors located at the bases of cilia of epithelial cells lining the respiratory tracts of humans and to its capsule, which provides protection from phagocytosis

Clonal Deletion (4)

- Occurs when lymphocytes mature - Vital that immune responses not be directed against autoantigens - Body eliminates self-reactive lymphocytes - Lymphocytes that react to autoantigens undergo apoptosis

Giardiasis

- Often asymptomatic protozoan disease - Diarrhea and associated GI symptoms can last up to four weeks. 'Rotten-egg' smell due to H2S --> Severe greasy, frothy, fatty diarrhea - Caused by Giardia intestinalis - Cysts are resistant to chlorine, heat, drying, and stomach acid - Trophozoites in small intestines interfere with breakdown and absorption leading to undigested food which is then broken down by bacteria - Once trophozoite enters colon --> cyst

Epidemioloy of Lyme Disease

- One of the most reported vector-borne diseases in United States - Three events contributed to an increase in Lyme disease --> Movement of human populations into woodland areas --> Protection of the deer population --> Coyotes have displaced the foxes that help control the mouse population

Precipitation Test - immune testing

- One of the simplest of serological tests - Antigens and antibody mixed in the proper proportion form large complexes called "precipitates" - Immunodiffusion --> Determines optimal antibody and antigen concentrations

Normal microbiota of the female reproductive system

- Only the vagina is colonized by various microorganisms, depends on hormone levels - Candida (fungus)

acquired immunodeficiency syndrome (AIDS) (3)

- Opportunistic infections, low Helper T cells, and presence of HIV - severe decrease in the number of CD4+ (<200 cells per μl of blood or less than 14% of T lymphocytes) and a positive test showing the presence of antibodies against HIV - often results in dementia during the final stages

Pathogenesis and Epidemiology of bacterial intoxications (toxifications) (food poisoning)

- Outbreaks are usually associated with picnics, school cafeterias, or large social functions where food stands unrefrigerated or where food preparation is less than optimal - Staphylococcus does not change the appearance or taste of food - often self-limiting and relatively mild

Epidemiology of Pseudomonas Infections (6)

- P. aeruginosais rarely part of the microbiota - because of its ubiquity and virulence factors, this opportunistic pathogen is involved in about 10% of healthcare-associated infections and colonizes most immunocompromised patients - Can infect almost any organ or system once in the body --> esides skin infections, it can be involved in bacteremia, endocarditis, and urinary, ear, eye, nervous system, gastrointestinal, muscular, and skeletal infections --> Infections in cystic fibrosis patients and in burn victims are most common --> Almost two-thirds of burn victims develop environmental or healthcare-associated Pseudomonas infections

Dendritic Cells (4)

- PRIMARY APC - have many long, thin cytoplasmic processes called dendrites - Phagocytic dendritic cells are found under the surface of the skin and mucous membranes - After acquiring antigens, dendritic cells migrate to lymph nodes to interact with cells of adaptive immunity

Spongiform encephalopathies

- PRION DISEASE - A class of diseases that includes scrapie and "mad cow" disease - Leave the brains of victims full of holes - Can occur spontaneously in the elderly - Humans can contract by eating meat from infected cattle

Pathogenesis and epidemiology of Endocarditis

- Patients usually have obvious source of infection --> Infected tooth, skin lesion, or intravascular catheter - Patients with abnormal heart have increased risk --> Birth defects, scarring, heart valve replacements

tissue typing (6)

- Physicians examine the white cells of potential graft recipients to determine what MHC proteins they have - donor organs are typed too - the potential recipient whose MHC proteins most closely match those of the donor is chosen to receive the graft - the closer the match, the less intense the rejection process and the greater the chance of successful grafting - match of 50% or more of the MHC proteins is usually acceptable for most organs - near absolute matches are required for successful bone marrow transplants

Artificially Acquired Active Immunity (3)

- Physicians induce immunity in their patients by introducing antigens in the form of vaccines - patients' own immune systems then mount active responses against the foreign antigens - "injection of immune serum (gamma globulin)"

Pathogen of Pneumocystis pneumonia (PCP)

- Pneumocystis jirovecii --> normal member of the respiratory microbiome, is an obligate parasitic ascomycete formerly known as "P. carinii."

Klebsiella Pneumonia

- Pneumonia symptoms combined with a thick, bloody sputum ("currant jelly") due to destruction of alveoli - Klebsiella pneumonia patients often have recurrent chills - Mortality rates are higher than with pneumococcal or mycoplasmal pneumonias

Pathogen and pathogenesis of Poliomyelitis

- Poliovirus (+ssRNA) from genus Enterovirus - 3 strains can be distinguished by antigens - Transmitted most often by drinking contaminated water. - viruses are replicated in cells of the throat and small intestine, producing initial symptoms of sore throat and nausea - Viruses then infect lymph nodes and from there enter the blood - viremia may progress to infection of neurons of the CNS - Paralysis develops following destruction of motor neurons in the upper spinal cord and brain stem; poliovirus does not infect muscles

Memory B Cells (4)

- Produced by B cell proliferation but do not secrete antibodies - Have BCRs complementary to the epitope that triggered their production - Long-lived cells that persist in the lymphoid tissue (20+ yrs) - Initiate antibody production if antigen is encountered again

Epidemiology of C. diff. (Antimicrobial-Associated) Diarrhea

- Pseudomembranous colitis is a by-product of modern medicine; until the widespread use of antimicrobial drugs, the condition was very rare --> Almost any antimicrobial can trigger the disease, but long-term use of newer, more powerful drugs are more likely to cause problems - elderly, burn patients, immunocompromised individuals, patients who have had a previous case of pseudomembranous colitis, and patients with kidney failure or who are recovering from abdominal surgery are particularly susceptible

Pathogen of Pseudomonas Infection (5)

- Pseudomonas aeruginosa is the causative agent --> G-, coccobacillus --> Blue-green color from the bacterial pigment, pyocyanin, occurs in massive infections --> most common microorganism seen in burn victims --> may also infect other parts of the body, particularly the lungs. (Cystic fibrosis patients are at particular risk.)

Complications of Eryispelas (2)

- Pyrogenic toxin may cause toxic shock syndrome --> High fever, low blood pressure, malaise, confusion, coma, multiple organ failure and death

Pathogen of Respiratory syncytial virus (RSV) infection

- RSV (genus Pneumovirus, family Paramyxoviridae) is an enveloped, helical, −ssRNA-ssRNA virus - relatively unstable outside the body, surviving only about five hours in the environment or two hours on skin or used facial tissues - Soap and water as well as disinfectants deactivate RSV

T Cell Regulation (6)

- Regulation needed to prevent T cell response to autoantigens - TH cells require additional signals from an antigen-presenting cell --> Interaction of the TH cell and antigen-presenting cell stimulates the TH cell to respond to the antigen --> APC will secrete IL-12 to fully activate TH cell - TC cells require IL-2 from TH cell to fully activate - Regulatory T cells also moderate cytotoxic T cell activity

Limitations of passive immunotherapy antisera/antiserum? (3)

- Repeated injections of animal-derived antisera can trigger allergic reactions called "serum sickness"; immune response against animal antigens - Antibodies of antisera are degraded relatively quickly; protection isn't long-lasting - Individual not protected from subsequent infections; memory B cells ARE NOT FORMED in response to passive immunotherapy

Regulatory T lymphocyte, TReg

- Represses adaptive immune responses (hopefully after successfully eliminating threat) - AKA "suppressor T cells" - activated by contact with other immune cells - secrete different cytokines than Helper T cells - suppress immune responses and promote tolerance of certain antigens

Epidemiology of Common Cold

- Rhinoviruses are highly infective, 100,000 virions/ml of nasal mucus. Viable for hours. - Spread by coughing/sneezing, fomites, or personto- person contact - Develop some immunity to serotypes over time

Pathogen and Pathogenesis of Rubella (4)

- Rubella virus (Rubivirus) is an enveloped, icosahedral, single-stranded RNA virus - infects cells of the upper respiratory tract and spreads from there to lymph nodes, into the blood, and then throughout the body via the blood - does not kill infected cells, but it does cause dividing cells to make errors during DNA replication - severity of rubella in adults is attributed to cell death resulting from a cell-mediated immune response against virally infected cells

Pathogenesis of Bacterial Meningitis

- S. agalactiae acquired during birth (infected birth canal) - Listeria transmitted via contaminated food or drink - Humans inhale N. meningitidis, H. influenzae, and S. pneumoniae in respiratory droplets from infected individuals (who may appear healthy) - In most cases, bacteria spread to the meninges from infections of the lungs, sinuses (sinusitis), or inner ear (otitis media) via the blood (bacteremia) --> The bacteria, somewhat protected by their capsules from phagocytosis, metabolize glucose in the CSF. - If becomes systemic can lead to disseminated intravascular coagulation

Pathogenesis and epidemiology of African Viral Hemorrhagic Fevers

- S/S 2-21 days after infection for Ebolavirus and 5-10 days with Marburgvirus - Causes severe dehydration and hemorrhaging - DIC: malfunctioning blood clotting causes hemorrhaging --> DIC: blood clots in small vessels, removes platelets necessary elsewhere - Occurs primarily in Africa - Transmitted via contact with bodily fluids of infected individual

Inactive (killed) vaccines (PROF NOTES)

- Safer than attenuated vaccines - Whole-agent vaccines - Subunit vaccines --> Antigenic fragments of microbe - Microbes don't provide many antigenic molecules to stimulate the immune response - Often contain adjuvants --> Chemicals added to increase effective antigenicity

Salmonellosis and Typhoid Fever

- Salmonella enterica serotypes (G- bacillus) - Typhi and Paratyphi cause typhoid fever - Enteritidis and Typhimurium cause salmonellosis - Bacteria tolerate acidity of stomach and pass to the intestine and reproduce in vesicles - Type III secretion system introduces toxins that disrupt numerous cellular activities, cause death --> Death of intestinal cells cause fever, cramps, diarrhea - Typhoid fever acquired by contaminated food or water - Salmonellosis often acquired by consuming contaminated eggs

Microbial Diseases of the Eye

- Senses are important part of the nervous system - Vision comprises almost half of the function of the cerebrum - Bacterial infections of skin and reproductive tract can affect the eyes

Type III Secretion System

- Sensory probe to detect the presence of eukaryotic organisms and injects proteins inside of them. Yersinia preferentially targets dendritic cells, neutrophils, or macrophages. - Antiphagocytic proteins are secreted directly from the bacterial cell into immune cell and shut down phagocytosis and cytokine release.

Pathogens and Virulence Factors of Septicemia, Bacteremia, and Toxemia

- Septicemia and toxemia caused by various bacteria --> Often opportunistic or HAI --> Pseudomonas aeruginosa, Neisseria meningitidis, Escherichia coli, Salmonella, Staphylococcus aureus, Streptococcus pneumoniae - Septicemia caused more often by Gram-negative bacteria - Bacteria that produce capsule may resist phagocytosis --> allowing the bacteria to continue reproducing and metabolizing in the blood - "stealing" iron from carrier proteins in the plasma via siderophores (iron is necessary for metabolism) - Other bacteria destroy erythrocytes, releasing iron from hemoglobin into the blood and making it available for bacterial growth - Endotoxin produced by Gram-negative bacteria

Pathogenesis and epidemiology of Septicemia, Bacteremia, and Toxemia

- Septicemia is due to direct inoculation of bacteria into the blood - Immunocompetent individuals rarely have septicemia --> Bacterial infections self-limited in these people - Gram-negative bacteria more often produce severe septicemia --> Due to release of endotoxin as the bacteria die

Diagnosis, Treatment, and Prevention of viral gastroenteritis

- Serological tests performed on stool samples can distinguish among surface antigens of caliciviruses, astroviruses, and rotaviruses. - The xTAG Gastrointestinal Pathogen Panel can identify noroviruses and rotavirus strain A. - There is no specific treatment for any of these infections except support and replacement of lost fluid and electrolytes. - Antidiarrheal medications may only prolong symptoms, because diarrhea tends to clear the viruses from the system. - Prevention involves adequate sewage treatment, purification of water supplies, frequent handwashing, good personal hygiene, and disinfection of contaminated surfaces and fomites. - Attenuated oral vaccines against rotaviruses exist and safely protect against up to 98% of severe rotaviral diarrhea cases that would require hospitalization. - Depending on which of two vaccines, pediatricians administer two or three doses beginning at two months of age.

Acquired Immunity

- Specific immunity acquired during an individual's life - distinguished as either Active or Passive Naturally Acquired - Response against antigens encountered in daily life Artificially Acquired - Response to antigens introduced via a vaccine

Vaginal Candidiasis

- Severe vaginal itching and burning intensified by urination - Growth of white mucoid colonies - Most commonly caused by Candida albicans - Normal microbiota of skin and mucous membranes - Candida overgrows if vaginal pH becomes alkaline or normal microbial populations are reduced --> Can become systemic in the immunocompromised - Can be passed person-to-person via birth or sexual intercourse - Identification of Candida in presence of symptoms is diagnostic - Treated with topical azole cream or oral fluconazole - Avoiding excessive use of antibacterial drugs can prevent candidiasis

Diagnosis, treatment, and prevention of Common Cold

- Signs and symptoms are usually diagnostic - Pleconaril can reduce duration of symptoms --> FDA rejected in 2002 because side effects of headache, diarrhea, and nausea - Antihistamines, decongestants, and pain relievers relieve the symptoms but do not reduce the duration of the disease - Hand antisepsis is important preventive measure

Diagnosis, treatment, and prevention of Septicemia, Bacteremia, and Toxemia

- Signs and symptoms are usually diagnostic - Treat with prompt diagnosis and administration of antimicrobial drugs - Prevention includes immediate treatment of infections - Important in individuals with compromised immune systems - If treatment is delayed, bacteria multiply, and the use of antimicrobial drugs can actually worsen a patient's condition by causing the release of large amounts of endotoxin

Diagnosis, treatment, and prevention of Influenza

- Signs and symptoms during a community-wide outbreak are often diagnostic - Treatment involves supportive care to relieve symptoms - Oseltamivir (Tamiflu) and zanamivir (Relenza) can be administered early in infection --> Block Neuraminidase, new virions can't be released --> Reduces duration of symptoms - Prevent by immunization with a multivalent vaccine

Viral Meningitis

- Similar to those of bacterial meningitis --> fever, severe headache, stiff neck, drowsiness, confusion, nausea, and vomiting --> some cause skin rashes, sore throats, and colds - death is rare - Usually milder than those of bacterial or fungal meningitis

Herpes Infections (9)

- Slow spreading skin lesions, recurrence of lesions is common. --> After a primary infection, herpesviruses often enter sensory nerve cells and are carried by cytoplasmic flow to the base of the nerve, where they remain latent in the trigeminal, sacral, or other ganglia --> Latent viruses may reactivate later in life as a result of immune suppression caused by stress, fever, trauma, sunlight, menstruation, or disease, and they may travel down the nerve to produce recurrent lesions as often as every two weeks. --> Fortunately, recurrent lesions are rarely as severe as those of initial infections because of immunological memory - About a week after infection, the viruses produce painful, itchy skin lesions on the lips (called fever blisters or cold sores) or genitalia (called genital herpes) - flulike signs and symptoms, including malaise, fever, and muscle pain - herpetic gingivostomatitis (Severe infections in which the lesions extend into the oral cavity) are most often seen in young patients and in patients with lowered immune function due to disease, chemotherapy, or radiation treatment - whitlow (inflamed blister) may occur on a finger if herpesvirus enters a cut or break in the skin of a finger - herpes gladiatorum occurs almost anywhere on athletes' skin as a result of contact with herpes lesions during sports

Genital Herpes

- Small blisters on or around the genitals or rectum - Human herpesvirus 2 (HHV-2) causes most cases, but can be caused by HHV-1 --> HHV are dsDNA viruses - Virus can become latent as circular DNA in nerve cells - Herpesvirus kills epithelial cells at infection site - Blisters may form at sites far from initial infection site, rupture and release millions of HHV. Turn into a painful lesion ulcer - Genital herpes quadruples the risk of HIV infection - Infants may be infected during birth - 15% of US have HHV-1, 40% have HHV-2 - Diagnosis made based on characteristic lesions - Administration of acyclovir or other antiviral agents can lessen symptoms - Condoms often provide little protection - Prevent through abstinence or mutual monogamy - Infected pregnant women should deliver by C-section

Epidemiology of Poxviruses (6)

- Smallpox has 2 strains --> Variola Major: severe disease with a mortality rate of 20% to 40% or higher, depending upon the age and general health of the host --> Variola Minor: has a mortality rate of less than 1% - increase in monkeypox cases over past decade; US midwest 2003 epidemic --> humans moving into monkey habitats in Africa, import of pets from Africa - elimination of smallpox and the cessation of smallpox vaccination may have led to increased human susceptibility to monkeypox because smallpox vaccination also protects against monkeypox

Pathogenesis of Poxviruses (9)

- Smallpox infection occurs by inhalation of virus, other Poxviruses spead via direct contact. --> Smallpox viruses replicate in the respiratory tract and then spread via the blood and lymph throughout the body, causing the characteristic lesions on the skin about 12 days following infection and killing up to 40% of patients - smallpox crusts can remain infective for 2 years - Unlike other DNA viruses, poxviruses replicate in cytoplasm - Death 30-100% of cases via: --> Dehydration (due to vesicles pulling water from body), pneumonia, encephalitis --> Pox filled throat causing suffocation --> Infection of pox lesions --> Produces anti-interferon to shut down immune response

Immune Response Cytokines (4)

- Soluble regulatory proteins that act as intercellular signals - Cytokines secreted by various leukocytes - Cytokine network --> The complex web of signals among all the cells of the immune system

Prostaglandins (2)

- Some contract smooth muscle; others relax it - lipid molecules that are powerful inflammatory agents

Fluorescent Immunoassays (3) - labeled immunoassay

- Some fluorescent dyes can be chemically linked to an antibody without affecting the antibody's ability to bind antigen - When exposed to a specific wavelength of light (as in a fluorescence microscope), the fluorescent dye glows - used in direct and indirect immunoassays

Wound Mycoses (3)

- Some fungi grow in deep tissues but do not become systemic (they do not spread throughout the body's systems) - eventually grow into the epidermis to produce skin lesions - Ex. chromoblastomycosis and phaeohyphomycosis, which are similar mycoses caused by melanin-producing, dark-pigmented fungi; mycetoma; and sporotrichosis

Diptheria

- Sore throat, localized pain, fever, and pharyngitis - Pseudomembrane that can obstruct airways --> Thickening of an oozing fluid composed of intracellular fluid, clotting factors, WBC, bacteria, and remains of dead pharyngeal and laryngeal cells.

makeup of the vaginal microbiome affects women's risk of infection with HIV (2)

- Specifically, the presence of inflammation-inducing bacteria, such as the Gram-negative Prevotella bivia, increases a woman's risk of infection with HIV by almost 13 times compared to women whose microbiome contains acidifying Gram-positive bacteria such as Lactobacillus. - Women in southern Africa more commonly have P. bivia, and this may explain in part why women in southern Africa have higher HIV infection rates than do women in other parts of the world.

Toxoplasmosis Symptoms in the fetus

- Spontaneous abortion, stillbirth, epilepsy, and mental retardation

Epidemiology of Streptococcal Respiratory Diseases

- Spread via respiratory droplets - Occurs most often in winter and spring

Pathogenesis of Pityriasis versicolor; superficial mycoses (3)

- Superficial fungi produce keratinase, an enzyme that dissolves keratin - These fungi do not penetrate living tissues and do not trigger immune responses --> this differentiates them from the cutaneous and subcutaneous pathogens

2 Major Groups of Autoimmune Disease

- Systemic Autoimmune Diseases (Ex. lupus) - Single-organ autoimmune diseases (common examples affect blood cells, endocrine glands, nervous tissue, or connective tissue)

Serology

- The analysis of blood to determine the presence of particular antigens or specific antibodies

Pathogen and virulence factors of Scabies (3)

- The mite Sarcoptesscabieiis the causative agent - Inflammation and damage to nerve endings occur as the mites burrow --> its antigens trigger inflammation

Epidemiology of Arboviruses

- The normal host for encephalitis arboviruses is either a bird (viruses of EEE, WEE, St. Louis encephalitis, and West Nile encephalitis) or a rodent (viruses of VEE and California encephalitis) - People who engage in work or recreation outdoors in endemic areas are at risk of accidental infection, and those older than 50 are at a higher risk of contracting EEE, St. Louis encephalitis, and West Nile encephalitis. - Children are at higher risk for WEE, VEE, and California encephalitis.

Positive result of fluorescent immunoassays

- The presence of fluorescence indicates the presence of the labeled anti-antibodies, which are bound to serum antibodies bound to the fixed antigen - fluorescence indicates that the individual has serum antibodies against the antigen of interest.

Diagnosis, treatment, and prevention of Impetigo (Pyoderma) (3)

- The presence of vesicles is diagnostic - Treat with oral and topical antimicrobials and careful cleaning of infected areas - Prevent with proper hygiene and cleanliness

Pathogenesis and epidemiology of Infectious Mononucleosis

- Transmission occurs via saliva - HHV-4 infects B lymphocytes - 90% of adults in U.S. have evidence of previous HHV- 4 infection - Due to a vigorous immune response upon initial infection of HHV-4 - Infectious mononucleosis results from a "civil war" in which cytotoxic T lymphocytes kill infected B lymphocytes. This "war" is responsible for the symptoms and signs of mono

Epidemiology of Pityriasis versicolor; superficial mycoses (3)

- Transmission of the fungi of pityriasis onto the surface of the skin is usually mediated via shared hairbrushes and combs, and several members of a family may be infected at the same time - Adolescents are more likely to be afflicted, possibly as a result of increased sebum production related to hormonal changes - In severely immunocompromised patients, superficial infections can spread to cover significant areas of skin or invade deeper tissues and become systemic

Pathogenesis and epidemiology of Plague

- Transmitted by contact with infected animal or flea feces --> Flea bite causes wound which allows bacteria to enter via flea feces - Causes bacteremia and disseminated intravascular bleeding -> black death - Bubonic plague fatal in 50% of cases if untreated - Pneumonic plague fatal in 100% of cases if untreated. May be in 24 hours after symptoms.

Epidemiology of Impetigo (Pyoderma) (2)

- Transmitted by person-to-person contact or via fomites - Occurs most in children

Pathogenesis and epidemiology of American Trypanosomiasis (Chagas' Disease)

- Transmitted through the bite of infected Triatoma or transfusion with infected blood - T. cruzi infects macrophages and heart muscle cells. Heart failure appears after infection. - Progresses through four stages over several months

Pathogenesis and Epidemiology of Tularemia

- Transmitted via bite of infected arthropod or contact with infected animal. - Small size of bacteria allows entry through seemingly unbroken skin - Individuals in contact with dead animals at highest risk - Inhaling only about 50 cells can cause disease, though a person would have to consume 108108 cells in food or drink to contract the disease via the digestive tract - NO human-human spread

Pathogenesis of Rabies

- Transmitted via bite or scratch from an infected animal - Rabies virus attaches to skeletal muscle cells, triggering its own endocytosis - Virus replicates in the cytoplasm of muscle cells and then moves into neurons. The virus will then travel up the neuron into the brain. Exact mechanism is unknown - Rabies virus attaches to skeletal muscle cells, triggering its own endocytosis - Viruses travel back to the periphery, including the salivary glands, through cranial and spinal nerve cells --> Viruses are secreted in the saliva of infected mammals

Epidemiology of Influenza

- Transmitted via inhalation of viruses or by selfinoculation (transfer from fingers to mouth/nose) - Infection provides some immunological protection from similar strains - Complications occur most often in the elderly, children, and individuals with chronic diseases

Amebiasis

- a mild to severe dysentery that, if invasive, can cause the formation of lesions in the liver, lungs, brain, and other organs - Entamoeba hisolytica causes - least severe form, luminal amebiasis, occurs in otherwise healthy individuals and is asymptomatic - Invasive amebic dysentery is a more serious form of infection characterized by severe diarrhea, colitis (inflammation of the colon), appendicitis, ulceration of the intestinal mucosa, bloody mucus-containing stools, and pain - most serious disease—invasive extraintestinal amebiasis—potentially fatal lesions of dead and dying intestinal cells form in the liver, lungs, spleen, kidneys, or brain

Syphilis

- Treponema pallidum causes syphilis --> G- spirochete --> Only lives in humans; heat, disinfectants, soaps, drying, atmospheric oxygen destroy it --> Too narrow to see with light microscope - Major virulence factors have been difficult to identify --> Virulent strains have a glycocalyx and hyaluronidase - Transmitted mostly via sexual contact - Sometimes transmitted from mother to child - 66% of individuals do not develop tertiary syphilis - Syphilis occurs worldwide - Diagnose primary, secondary, and congenital syphilis with antibody test or dark-field microscopy - Tertiary syphilis is difficult to diagnose, not an active infection - Penicillin G used to treat all but tertiary syphilis - No proven alternative treatment for those allergic to penicillin - All sexual partners of syphilis patients must be treated with prophylactic penicillin G

Diagnosis, treatment, and prevention of tuberculosis

- Tuberculin skin test identifies exposure to tuberculosis - Chest X-rays can identify tubercles in the lungs - Treatment requires combination of drugs for 6 months - Drug-resistant strains of M. tuberculosis have emerged. MDR and XDR (extensively) strains. - BCG vaccine available where tuberculosis is common

Pathogen and virulence factors of herpes infections (6)

- Two enveloped viral species of Simplexvirus cause herpes: human herpesvirus 1 (HHV-1) and human herpesvirus 2 (HHV-2). - Caused by Human alphaherpesviruse 1 and 2 (dsDNA) --> HHV-1 (above the waist), HHV-2 (below the waist) (neonatal) THOUGH EITHER CAN OCCUR ANYWHERE - Inhibits the transporter associated with antigen processing (TAP). Prevents cytosolic peptides from entering ER, and presentation on MHC I. - glycoproteins in the viral envelope mediate viral adhesion and fusion - other proteins inactivate complement and gamma class antibodies (IgG)

4 Types of Hypersensitivities

- Type I (immediate) - Type II (cytotoxic) - Type III (immune complex-mediated) - Type IV (delayed or cell-mediated)

Streptococcal Respiratory Diseases

- Typically streptococcal pharyngitis (strep throat), but may spread to lower respiratory system - Sore throat and difficulty swallowing, fever, malaise and headache - Laryngitis and bronchitis can occur if infection spreads to lower respiratory tract --> Laryngitis manifests as hoarseness --> bronchitis reduces airflow, encourages mucus accumulation in the lungs, and triggers coughing - May progress to scarlet or rheumatic fever - Scarlet fever (scarlatina): bacteriophage infecting bacteria codes for toxin --> Rash begins on chest and spreads. Tongue usually becomes strawberry red --> after one to two days of pharyngitis, such streptococci release their toxins, triggering fever and a rash that begins on the chest and spreads across the body - Rheumatic fever: antibodies made against bacteria trigger autoimmunity against heart

Graft-Versus-Host Disease (3)

- Unfortunately, when they are transplanted, donated bone marrow T cells may regard the patient's cells as foreign, mounting an immune response against them - If the donor and recipient mainly differ in MHC class I molecules, the grafted T cells attack all of the recipient's tissues, producing especially destructive lesions in the skin and intestine - If the donor and recipient differ mainly in MHC class II molecules, then the grafted T cells attack the antigen-presenting cells of the host, leading to immunosuppression and leaving the recipient vulnerable to infections

Dengue Fever and Dengue Hemorrhagic Fever

- Up to three-fourths of people infected with dengue virus are asymptomatic - Dengue fever is usually a mild disease - Dengue hemorrhagic fever is more severe and can be fatal (20% if untreated, 1% if treated). Dengue fever (break-bone fever) - First phase: fever, edema of limbs, severe head and muscle pain. Followed by 24-hour gap. - Second phase: return of fever and bright red rash Dengue hemorrhagic fever: hyperimmune response - Follows reinfection with a dengue virus - activated memory T cells release inflammatory lymphokines that trigger rupture of blood vessels, internal bleeding, shock, and possibly death

Normal Microbiota of the Urinary System

- Urethra supports colonization by some microorganisms --> Microorganisms in the urethra can move up to infect the kidneys - Remainder of the urinary organs are sterile --> because of the normally acidic pH of urine and the flushing action of urination - Bacteroides, Lactobacillus, Staphylococcus, Streptococcus, Mycobacterium - Opportunistic and sexually transmitted microbes can infect the reproductive system

Antigens for Allergic Contact Dermatitis - Type 4 (5)

- Urushiol, the oil of poison ivy and related plants --> small molecule that becomes antigenic when it binds to almost any protein it contacts (proteins in skin) - formaldehyde - some cosmetics, dyes, drugs, and metal ions - chemicals used in the production of latex for hospital gloves and tubing

Tapeworm Infestations

- Usually asymptomatic, unknown until segments of helminth are passed - Nausea, abdominal pain, weight loss, and diarrhea may occur - Taenia saginata: beef tapeworm - Taenia solium: pork tapeworm - Life cycle divided between a primary and intermediate host --> Humans = primary host --> Cows/pigs= intermediate host

Microbiome of the Tongue and Teeth

- Viridans streptococci are most prevalent - Actinomyces, Lactobacillus, Corynebacterium, Haemophilus, Staphylococcus, Entamoeba (protozoan), Trichomonas (protozoan)

Lymphocytes (5)

- WBC that acts against specific pathogens - when resting, they're the smallest WBC - form in red bone marrow --> sites contain blood stem cells (hematopoietic stem cells), which are cells that give rise to all types of blood cells --> This is why a bone marrow transplant can restore a person's entire adaptive immune system

Leptospirosis

- Zoonotic disease primarily seen in animals - Abrupt fever, rash, myalgia, muscle stiffness, and headache - Jaundice may develop in severe infection - Rarely fatal but due to kidney and liver failure, meningitis, or respiratory distress - Caused by Leptospira interrogans --> G- spirochete - Grows asymptomatically in many wild and domestic animals - Transmitted by contact with urine of infected animal or urine-contaminated water - Results in bacteremia, often concentrating in the kidney and liver causing severe or fatal damage. - Rare in the U.S. - Tropics/subtropics or in poor living conditions - Diagnosis based on antibody test - Treat with antimicrobial drugs --> Intravenous penicillin G treats severe infections; oral doxycycline, ampicillin, or amoxicillin are drugs of choice for less severe cases - Prevent by avoiding contaminated water

Azathioprine - cytotoxic drug (3)

- a purine analog --> competes with purines during the synthesis of nucleic acids --> thus blocking DNA replication and suppressing both primary and secondary antibody responses

cytopathic effect (2)

- a visible effect on a host cell, caused by a virus, that may result in host cell damage or death - viruses introduced into appropriate cell cultures will invade and kill the cells

How are B and T lymphocytes differentiated by scientists? (2)

- according to surface proteins that are part of each lymphocyte's cytoplasmic membrane - These proteins allow lymphocytes to recognize specific pathogens and toxins by their molecular shapes, and the proteins play roles in intercellular communication among immune cells

Memory T Cells

- activated T cells become memory T cells - can persist in "suspended animation" for months to years in lymphoid tissue - Immediately functional upon subsequent contacts with epitope-MHC complex specific to its TCR

Alternative Pathway of Complement Activation (3)

- activation occurs independently of antibodies with the cleavage of C3 into two fragments, C3a and C3b - Triggered when activated complement proteins (C3b) bind to the surface of microorganisms - useful in the early stages of an infection, before the adaptive immune response has created the antibodies needed to activate the classical pathway

Unresponsiveness to Self (2)

- adaptive immunity does not act against normal body cells --> "self-tolerant"

What is the key to enduring protection? (2)

- adaptive immunity is unresponsive to self - adaptive immunity involves immunological memory brought about by long-lived memory B and T cells

Virulence Factors of Poxviruses (3)

- adhesion molecules allow them to attach to a host cell's cytoplasmic membrane, where they trigger their own endocytosis - Unlike other DNA viruses, they carry genes for transcription enzymes, which allow them to replicate entirely in the cytoplasm of a cell - viruses also code for proteins that interfere with the actions of interferon, complement, and inflammation

How is RA treated? (2)

- administering anti-inflammatory drugs such as ibuprofen to prevent additional joint damage - immunosuppressive drugs to inhibit the antibody immune response

Cryptococcal meningitis (cryptococcosis)

- affects healthy and sick/immunocompromised people - symptoms common to bacterial meningitis: headache, dizziness, drowsiness, irritability, confusion, nausea, vomiting, light sensitivity, and neck stiffness --> late stages: blindness and coma - Acute onset of rapidly fatal cryptococcal meningitis occurs in individuals with widespread infection

hemagglutination (3)

- agglutinated red blood cells - used to determine blood type in humans --> antibodies agglutinate those blood cells that possess corresponding antigens

agglutination vs. precipitation (3)

- agglutination involves the clumping of insoluble particles - precipitation involves the clumping of soluble molecules - Agglutination reactions are sometimes easier to see and interpret with the unaided eye

Hay Fever - LOCAL

- allergic reaction localized to the upper respiratory tract and characterized by nasal discharge, sneezing, itchy throat and eyes, and excessive tear production

Immunochromatographic assays (4)

- antigen molecules form visible immune complexes with antibodies labeled with a colored substance - fast and easy-to-read immunoassays - an antigen solution (such as diluted blood or sputum) flowing through a porous material encounters antibody labeled with either pink colloidal gold or blue colloidal selenium - Where antigen and antibody bind, colored immune complexes form in the fluid, which then flows through a region where the complexes encounter antibody against them, resulting in a clearly visible pink or blue line, depending on the label used

Artificially Acquired Passive Immunity (3)

- antisera or antitoxins - medical personnel routinely harvest antibodies specific for toxins and pathogens that are so deadly or so fast acting that an individual's active immune response is inadequate - They acquire these antibodies from the blood of immune humans or animals, typically a horse

Treatment of Graves' Disease (3)

- antithyroid medicines - radioactive iodine - Patients whose condition doesn't improve with those treatments may require surgical removal of most of the thyroid tissue

Hypersensitivity

- any immune response against a foreign antigen that is exaggerated beyond the norm - 4 types

Leishmaniasis (2) - parasitic infection of the skin

- any of the 3 clinical syndromes caused by a bite from a sand fly carrying Leishmania and ranging from painless skin unlcers to disfguring lesions to visceral leishmaniasis, which is systemic and fatal in 95% of untreated cases - an intracellular parasitic protozoan causes this disease of the skin and oral mucous membrane

B Lymphocytes (4)

- arise and mature in the red bone marrow of adults - Humoral/Antibody immune responses - carry out antibody immune responses - often directed against extracellular pathogens and toxins

T Lymphocytes (5)

- arise in red bone marrow - mature in the Thymus - Cell-mediated immune responses - act against intracellular pathogens and abnormal body cells (cancer cells) - 2 groups (helper T; cytotoxic T)

Pigeon Breeder's Lung - type of Hypersensitivity Pneumonitis

- arises following exposure to the dust from pigeon feces

Graves' Disease - Single-Organ Autoimmune Diseases (6)

- autoimmunity against endocrine organs - production of autoantibodies stimulates excessive production of Thyroid Hormone and the growth of the thyroid gland --> thyroid secretes iodine-containing hormones, which help regulate metabolic rate in the body - may be triggered by a viral infection in individuals with certain genetic backgrounds - Affected patients (usually women) make autoantibodies that bind to and stimulate receptors on the cytoplasmic membranes of thyroid cells, which elicits excessive production of thyroid hormone and growth of the thyroid gland --> patients develop an enlarged thyroid gland, called a goiter, and protruding eyes, rapid heartbeat, fatigue, and weight loss despite increased appetite

retina

- back interior wall of the eye - contains billions of sensory neurons that respond to light energy and send nerve impulses to the brain down the optic cranial nerve

Epidemiology of Acne (5)

- bacteria of acne are normal members of the microbiome that grow aggressively because of the large amount of sebum produced as a result of adolescent hormones, particularly testosterone - Typically begins in adolescence but can occur later in life - acne is not a reportable disease, so its exact prevalence is not known --> estimated that at least 75% of the world's adolescents develop acne at some time --> Severe cystic acne is much more rare

How are active immune responses advantageous? (2)

- because they result in immunological memory and protection against future infections - HOWEVER they are slow

Cutaneous Anthrax (11)

- begins when Bacillus anthracis endospores, often shed by an infected animal, enter a wound in the skin, producing a solid skin nodule --> facultatively anaerobic, endospore-forming, rod-shaped bacterium --> found naturally in soil - bacterium's capsule inhibits phagocytosis by white blood cells - bacterium synthesizes three toxins that kill cells in the affected area - nodule spreads to form a painless, swollen, black, crusty ulcer called an eschar - successfully treat cutaneous anthrax with oral antimicrobial drugs such as doxycycline or ciprofloxacin for 7-14 days - Treated cutaneous anthrax is rarely fatal - incubation period: Immediate response, within one day - The most commonly infected individuals are animal handlers - Prevention: Immunize livestock. The vaccine, considered safe for humans but recommended only for high-risk personnel, requires six doses over an 18-month period and annual boosters.

Epidermis (12)

- bloodless - consists of four to five layers, each composed of sheets of tightly packed cells - Basal cells of the epidermis, which adjoin the dermis, divide continuously, pushing their offspring toward the surface --> As the daughter cells are pushed away from the dermal blood supply, they flatten and die, but not before modifying themselves --> They absorb melanin, a pigment that is secreted by other cells in the basal layer and that gives skin its color --> the more melanin, the darker the skin - Epidermal cells also fill with a waterproofing protein called keratin --> A hardened type of keratin forms nails and hairs, which are accessory structures to the skin - Between the dying cells, defensive cells called dendritic cells phagocytize microbes that penetrate into the deeper layers of the epidermis and deliver microbial antigens to defensive lymphocytes - the outermost layer of skin consists of flattened, dead, dry, keratinized cells covered with oil and salt—a significant barrier to microbial invasion - skin sloughs off microbes attached to the outermost skin flakes as epidermal cells are continually pushed up from the basal layer --> body replaces the outer layers of the epidermis about once a month

major histocompatibility complex (MHC) proteins (8)

- body prepares for an adaptive immune response by making MHC proteins and processing antigens - Cells of adaptive immunity only recognize epitopes carried on MHC proteins - Mark self from non-self - Group of antigens first identified in graft patients - Important in determining compatibility of tissues for tissue grafting - Major histocompatibility antigens are glycoproteins found in the membranes of most cells of vertebrate animals - Hold and position antigenic determinants for presentation to immune cells - in humans, MHC is located on each copy of chromosome 6

Healing a Wound (3)

- body starts healing by forming a blood clot to temporarily close the breach - neighboring connective and epithelial cells multiply and grow into the clot to restore the skin's integrity - mostly phagocytosis, complement, and inflammation eliminate a wound infection

Fever (4)

- body temp over 39.4ºC (103F) or higher is a concern - Results when pyrogens trigger the hypothalamus to increase the body's core temperature - continues as long as pyrogens are present - side effects, including malaise, body aches, and tiredness - exact mechanism unknown

Structural Defenses Against Phagocytosis of Staphylococcus for Folliculitis (5)

- both S. aureus and S. epidermis synthesize loosely organized polysaccharide slime layers (sometimes called capsules) that inhibit chemotaxis of and phagocytosis by leukocytes --> slime layer also facilitates attachment of staphylococcal biofilms to artificial surfaces such as catheters, shunts, artificial heart valves, and synthetic joints - Cells of S. aureus are uniformly coated with protein A, which binds to the stems of class G antibodies (IgG) --> Antibodies are opsonins—they enhance phagocytosis—precisely because phagocytic cells bind to antibody stems --> protein A, by blocking the stems, effectively inhibits opsonization --> Protein A also inhibits the complement cascade, which is triggered by antibody molecules bound to antigen

Signs and Symptoms of Ehrlichiosis and anaplasmosis

- both manifest similarly with flulike signs and symptoms of fever, chills, nausea, muscle aches, and headache - Leukopenia (a decrease in the number of white blood cells in the blood) and thrombocytopenia (a decrease in the number of platelets) also occur - Diarrhea, malaise, or a fine pinhead rash - symptoms are usually quite general and minimal but may be life threatening, depending on the patient's age and general health

measure the concentration of antibodies in serum (3)

- can determine whether a patient's antibody levels are rising --> occurs in response to the presence of active infectious disease, or falling, as occurs during the successful conclusion of a fight against an infection - Ex. Titration

Pathogenesis of Warts (papillomaviruses) (5)

- cause infected epithelial cells to divide - cause the cells to develop distinctive vacuoles surrounding their nuclei and to form dense cytoplasm - incubation time from infection to the development of a wart is usually three to four months - most are harmless --> though papillomaviruses may precipitate various head, neck, anal, vaginal, penile, and oral cancers

chromoblastomycosis - wound mycoses (12)

- caused by melanin-producing, dark-pigmented fungi - Four species of ascomycete fungi (Fonsecaea pedrosoi; F. compacta; Phialophora verrucosa; Cladophialophora carrionii) - Painless lesions form that progressively worsen, becoming large, flat to thick, tough, and wartlike --> become tumorlike and extensive if not treated - Inflammation, development of fibrous tissue, and abscess formation occur in surrounding tissues - Often enter body via minor trauma (thorn or splinter) - Presence of golden-brown bodies in skin sample is diagnostic - Often CANNOT be cured - Treatment involves removal of infected tissues and administration of antifungal drugs; possible amputation (the earlier the treatment, the better chances) - prolonged course of thiabendazole and 5-fluorocytosine. - People who are barefoot on soil are at greatest risk - can spread throughout the body

Respiratory syncytial virus (RSV) infection

- causes the fusion of cells in the lungs and difficulty in breathing - the most common childhood respiratory disease in newborns and young children - the leading cause of bronchiolitis - four to six days following infection, RSV triggers fever, rhinorrhea (runny nose), cyanosis (blue cast to skin), coughing, and sometimes wheezing in babies and immunocompromised patients - some children develop tracheobronchitis, known commonly as croup, which is inflammation of the trachea and bronchi, resulting in breathing difficulty accompanied by a barking cough

T lymphocytes (7)

- cell-mediated immune responses - arise in red bone marrow, mature on thymus - account for about 70% to 85% of all lymphocytes in the blood - Circulate in the lymph and blood and migrate to the lymph nodes, spleen, and Peyer's patches - Have T cell receptors (TCRs) on their cytoplasmic membrane --> Antigen-binding sites are complementary to epitopes --> Every T cell randomly chooses and combines segments of DNA from TCR genes to create a new genetic combination specific to that cell, which codes for the cell's unique and specific TCR

neurotransmitters

- chemical messengers that cross the synaptic gaps between neurons - A particular neurotransmitter may be stimulatory or inhibitory --> either (1) stimulates a muscle to contract, a gland to secrete, or another neuron to carry a nerve impulse --> or (2) inhibits such activities.

Pyrogens (5)

- chemical that trigger hypothalamus "thermostat" to reset at a higher temp, triggering fever - Bacterial toxins - Cytoplasmic contents of bacteria released by lysis - Antibody-antigen complexes - Pyrogens released by phagocytes that have phagocytized bacteria

Toxoid Vaccines - Types of Vaccines (3)

- chemically or thermally modified toxins that are used in vaccines to stimulate active immunity - stimulate antibody-mediated (humoral) immunity - have few antigenic determinants so multiple doses along lifetime are required (every ten yrs)

How are antibodies acquired for the therapy?

- clinicians remove blood cells and clotting factors from the blood of donors - resulting antiserum contains IgG (gamma globulins) - often gathered from large animals intentionally exposed to a pathogen of interest, because the large blood volume of the animals contains more antibodies

Lymph

- colorless, watery - Liquid with similar composition to blood plasma - Arises from fluid leaked from blood vessels into surrounding tissues - carries toxins and pathogens to areas where lymphocytes are concentrated

Combination Vaccines - Types of Vaccines (3)

- combine antigens from several attenuated and inactivated pathogens and toxoids that are administered simultaneously - Ex. MMR-Var (ProQuad) works against measles, mumps, rubella - Ex. Pentacel works against diphtheria, tetanus, pertussis (whooping cough), polio, and diseases of Haemophilus influenzae

Tetanospasmin

- composed of two polypeptides held together by a disulfide bond' - The heavier of the two polypeptides binds to the cytoplasmic membrane of a neuron, triggering the neuron to endocytize the toxin and cleave off the lighter of the two polypeptides - Axonal transport carries the lighter polypeptide to the central nervous system - C. tetani remains localized at the site of infection; only the toxin moves to the central nervous system

Diagnosis, treatment, and prevention of Endocarditis

- confirmed by visualization of vegetations via an echocardiogram - Treat with intravenous antibacterial drugs --> Typically takes weeks - May need to surgically remove vegetations or repair damaged heart valves - Prophylactic antibiotics for high-risk patients when needed (prior to surgery/dental procedures)

VARIANT Creutzfeldt-Jakob Disease (vCJD)

- contagious form of spongiform encephalopathies derived from cattle - Insomnia, weight loss, and memory failure as brain tissue is destroyed - Progressive worsening of muscle control - death usually in 12 months

What happens if the fever is too high? (5)

- critical proteins are denatured - nerve impulses are inhibited --> hallucinations --> coma --> death

Cyclophosphamide - cytotoxic drug (2)

- cross-links daughter DNA molecules in mitotic cells, preventing their separation and blocking mitosis - impairs both B cell and T cell responses

chronic granulomatous disease - Primary Immunodeficiency Diseases (4)

- defect in the 2nd line of defense - children have recurrent infections due to the inability of their phagocytes to destroy bacteria --> these children have an inherited inability to make reactive forms of oxygen, which are necessary to destroy phagocytized bacteria - characterized by the development of large masses of inflammatory cells in lymph nodes, lungs, bones and skin

severe combined immunodeficiency disease (SCID) - Primary Immunodeficiency Diseases (5)

- defect in the 3rd line of defense (adaptive immunity) - some children fail to develop any lymphoid stem cells whatsoever --> they produce neither B cells nor T cells --> cannot mount immune responses - this causes recurrent infections

Diagnosis, Treatment, and Prevention of primary amebic meningoencephalopathy

- diagnose Naegleria infections by detecting amoebas in scrapings from the covering of the eye, cerebrospinal fluid, or biopsy material from the brain - Ketoconazole or amphotericin B may have very limited success, but only if administered very early - amoeba produces resistant cysts that are environmentally hardy; therefore, controlling and preventing infection can be difficult --> avoid waterways where the organism is present, sterile solution for contact lenses, proper cleaning of water-related systems

Diagnosis, Treatment, and Prevention of Shigellosis

- diagnose by shigella in the stool using xTAG Gastrointestinal Pathogen Panel - antimicrobial, such as ceftriaxone, which can shorten the duration of disease and reduce the spread of Shigella to other patients - Resolves in about 7 days - Resistance to antimicrobials among Shigella strains is widespread and increasing worldwide - vaccine in progress

Diagnosis, Treatment, and Prevention of Oral Herpes

- diagnosed by observation of the characteristic recurring lesions - Microscopic examination of infected tissue reveals syncytia. - Positive diagnosis is achieved by immunoassay that demonstrates the presence of viral antigen - Infections with HHV-1 or HHV-2 are among the few viral diseases that can be controlled with chemotherapeutic agents, notably valacyclovir. - Topical application of the drug limits the duration of the lesions and reduces viral shedding, though the drug does not cure the diseases or free nerve cells of latent viral infections. - Patients with active lesions are more likely to spread the disease, but asymptomatic carriers still shed viruses and are contagious - Washing with soap and water may minimize spread of the virus, - most effective prevention depends on avoiding direct contact with infected individuals.

Diagnosis, Treatment, and Prevention of Traveler's Diarrhea

- diagnosed by s/s - xTAG Gastrointestinal Pathogen Panel can identify three pathogenic strains of E. coli - replace lost fluids, electrolytes - Antimicrobials: doxycycline, trimethoprim-sulfamethoxazole, fluoroquinolones, or rifaximin - no vaccine - Antimicrobial drugs prolong the symptoms --> Cause O157:H7 to produce more Shiga-like toxin - Antidiarrheal drugs prolong the symptoms --> Delays expulsion of bacteria from digestive tract

Diagnosis, Treatment, and Prevention of Warts (papillomaviruses) (8)

- diagnosis is a simple matter of observation, though only DNA probes can determine the exact strain of Papillomavirus involved - treatment: Warts usually regress over time as the cell-mediated immune system recognizes and attacks virally infected cells. --> pain associated with some warts may necessitate removing infected tissue via surgery, freezing, cauterization (burning), laser, or the use of caustic chemicals, as are found in over-the-counter medications --> virus may remain latent in neighboring tissue and produce new warts at a later time - Laser surgery has the added risk of causing viruses to become airborne—some physicians have developed warts in their noses after inhaling airborne viruses during laser treatment of patients - Some patients have successfully removed warts by covering them with duct tape --> Covered warts usually disappear within two months - Most types of warts are difficult to prevent. However, genital warts may be prevented by abstinence, mutual monogamy, or vaccine

Pathogenesis of C. diff. (Antimicrobial-Associated) Diarrhea

- generally noninvasive; that is, it does not move from the colon into the blood --> stays within the lumen of the colon, producing its two toxins - Toxin A breaks down the junctions holding cells of the colon's mucous membrane together, which triggers inflammation and allows loss of fluid - Toxin B kills the colon's cells outright and induces the formation of lesions that fuse into the characteristic pseudomembrane - Each toxin enhances the action of the other toxin by mechanisms that are not understood

Diagnosis, Treatment, and Prevention of Ehrlichiosis and anaplasmosis

- diagnosis is difficult because their manifestations may be mild and they resemble other diseases - Physicians consider ehrlichiosis or anaplasmosis in any case of otherwise unexplained acute fever in patients exposed to ticks in endemic areas - Immunofluorescent antibodies against the bacteria inside white blood cells or polymerase chain reaction (PCR) tests can demonstrate infection, confirming a diagnosis - Doxycycline is effective against both Ehrlichia and Anaplasma - Treatment should start immediately, even before diagnosis is confirmed by serological testing, because the complications of infection and mortality rates increase when treatment is delayed - Prevention involves avoiding tick-infested areas, promptly removing ticks, wearing tight-fitting clothes, and using insect repellents - NO vaccine for either

Diagnosis, Treatment, and Prevention of Pneumocystis pneumonia (PCP)

- diagnosis relies on clinical and microscopic findings - Chest X-ray films usually reveal abnormal lung features - Stained specimens of fluid from the lungs or from biopsies can reveal distinctive morphological forms of the fungus --> The use of fluorescent antibody on samples taken from patients is more sensitive and provides a more specific diagnosis - Pneumocystis does not respond to antifungal drugs --> instead, both primary treatment and maintenance therapy are with an oral or intravenous combination of trimethoprim and sulfamethoxazole known as TMP-SMX - It is virtually impossible to prevent infection because P. jirovecii is ubiquitous in humans

Malassezia furfur - Pathogen of Pityriasis versicolor; superficial mycoses (3)

- dimorphic basidiomycete - normal inhabitant of human skin around the world - feeds on oil produced by the skin, causing infections that tend to be chronic

Plague

- disease caused by Yersinia pestis, often manifesting with enlarged lymph nodes (bubonic plague) or with severe pulmonary distress (pneumonic plague)

Epidemiology of Ehrlichiosis and anaplasmosis

- emerging diseases because they were unknown before 1987, and the number of reported cases has increased from a few dozen per year in the 1980s to over in 4500 in 2018 - increase is likely due in part to improved diagnosis and reporting

Streptococcus pneumoniae - pathogen of bacterial meningitis

- encapsulated Gram-positive coccus - opportunistically grow in the lungs, sinuses, and middle ear and from those locations move into the meninges via the blood - leading cause of meningitis in children less than 5 years old and in very old adults - polysaccharide capsule, which protects them from digestion after phagocytosis - pathogenic pneumococci also produce enzymes and toxins that enable the bacteria to counteract immune defenses - cell wall chemical called phosphorylcholine, which is an adhesin that binds to receptors on cells in the lungs, the meninges, and blood vessel walls --> Binding stimulates target cells to phagocytize the bacteria - the phosphorylcholine and polysaccharide capsule together enable pneumococci to "hide" inside body cells --> allows S. pneumoniae to pass across these cells into the blood and brain - grows in the mouths and throats of 75% of humans without causing harm --> in some patients, particularly children and the elderly—groups whose immune responses are not fully active—these pneumococci become bloodborne and invade the meninges

What does the increased temperature of a fever do? (5)

- enhances interferons - inhibits growth of some microbes - enhances phagocytes - enhances lymphocytes of adaptive immunity - enhances tissue repair process

Pathogenesis of Coccidioidomycosis

- enters the body through inhalation of arthroconidia from the soil - Disease begins as a generalized pulmonary infection that then spreads to the rest of the body - Arthroconidia germinate in the alveoli into a form called a spherule --> As each spherule matures, it enlarges and generates a large number of spores via multiple divisions, until it ruptures and releases the spores into the surrounding tissue --> Each spore then forms a new spherule to continue the cycle of division and release

Proteases (4)

- enzymes that destroy nearby cells, activating the complement system --> results in the release of more chemicals that cause inflammation - damage tissue - account for more than half the proteins in a mast cell granule

Peptic Ulcers

- erosions of the linings of either the stomach (gastric ulcer) or duodenum of the small intestine (duodenal ulcer) - abdominal pain - shock, in which the cardiovascular system fails to deliver enough blood to vital organs, is usually the major sign of a perforation - nausea, vomiting (with or without blood, which looks like coffee grounds in the vomitus), weight loss, chest pain, or black, tarlike stools

Diagnosis, Treatment, and Prevention of Pityriasis versicolor; superficial mycoses (8)

- examine the patient under ultraviolet illumination with a wavelength of 365 nm (NOT DEFINITIVE) --> patches of skin infected with M. furfur fluoresce pale green - Definitive diagnosis requires microscopic examination - Preparations of skin samples mixed with 10% KOH reveal both masses of budding yeast and short hyphal forms that are diagnostic for M. furfur - Superficial Malassezia infections are treated topically with solutions of ciclopirox or antifungal imidazoles, such as ketoconazole shampoos - topical applications of zinc pyrithione, selenium sulfide lotions, or propylene glycol solutions can be used - Oral therapy with ketoconazole may be required to treat extensive infections and infections that do not respond to topical treatments - relapses are common; prophylactic topical treatment may be necessary - skin takes months to regain its normal pigmentation following successful treatment

Systemic Mycoses

- fungal infections that affect numerous systems

Superficial Mycoses

- fungal infections that occur on the hair, nails, and outer skin layers; most common fungal infections - acquired by direct contact with the hyphae or spores of opportunistic fungi - Ex. Pityriasis

Common Allergens

- fungal spores - ragweed pollen - pollen from grasses, flowering plants, some trees - feces and dead bodies of house dust mites - latex - wool - certain metals - venom or saliva of wasps, bees, fire ants, deer flies, fleas, stinging biting insects

4 Immunosuppressive Drugs

- glucocorticoids - cytotoxic drugs - cylosporine - lymphocyte- depleting therapies

Epidemiology of Measles (6)

- highly contagious - Spread via respiratory droplets - More than 80% of unimmunized patients exposed to the virus develop symptoms 8-14 days later - only infects humans - a numerous, dense population of susceptible individuals must be present for the virus to spread via respiratory droplets from coughing and sneezing - In an unimmunized population, measles outbreaks typically occur in one- to three-year epidemic cycles as a critical number of susceptible individuals is reached

2 tick-borne diseases:

- human monocytic ehrlichiosis (HME) --> AKA "ehrlichiosis" - human granulocytic anaplasmosis (HGA) --> AKA "anaplasmosis"

two localized conditions resulting from immune complex-mediated hypersensitivity

- hypersensitivity pneumonitis - glomerulonephritis

Asthma (2) - LOCAL

- hypersensitivity reaction affecting the lungs and characterized by bronchial constriction and excessive mucus production - characterized by wheezing; coughing; excessive production of a thick, sticky mucus; and constriction of the smooth muscles of the bronchi

Diagnosis, Treatment, and Prevention of Histoplasmosis

- identification of budding yeast within macrophages or in stained samples of skin scrapings, sputum, cerebrospinal fluid, or various tissues --> diagnosis is confirmed by the observation of dimorphism in cultures grown --> produces distinctively spiny spores that are also diagnostic - antibody tests are not useful indicators of disease because many people have been exposed without becoming ill --> 90% of the US population has antibodies against H. capsulatum - immunocompetent patients often resolve without treatment - amphotericin B for one to two weeks followed by itraconazole for one year

Diagnosis, Treatment, and Prevention of amebiasis

- identification of microscopic, spherical cysts or pleomorphic trophozoites recovered from either fresh stool specimens or intestinal biopsies - Microscopic analysis is necessary to distinguish amebic dysentery from bacterial dysentery - Serological identification of antigens may be used to distinguish E. histolytica from nonpathogenic amoebae. - Treatment involves oral rehydration therapy (vital in severe cases) and antiamebic drugs. - Iodoquinol and paromomycin are effective for asymptomatic infections. - Physicians may prescribe metronidazole followed by iodoquinol for symptomatic amebiasis. - Antibacterial agents may also be prescribed to prevent secondary bacterial infections. - Antidiarrheal medications should be avoided because they may worsen the condition by retaining the organism in the intestinal tract.

Direct fluorescent immunoassays (5)

- immune test allowing direct observation of the presence of antigen in a tissue sample flooded with labeled antibody - If the suspected antigen is present, labeled antibody will adhere to it, and the scientist will see fluorescence - he amount of fluorescence observed is not directly related to the amount of antigen present - can identify small numbers of bacteria in patient tissues - Ex. detect Mycobacterium tuberculosis in sputum and to detect rabies viruses infecting a brain

Indirect fluorescent immunoassays (4)

- immune test allowing observation through a fluorescence microscope of the presence of antigen in a tissue sample flooded with labeled antibody - used to detect the presence of specific antibodies in an individual's serum via a three-step process - can detect antibodies against many viral, bacterial , or protozoan pathogens --> presence of antibodies indicates that the patients have been exposed to the pathogen and may need treatment or counseling on steps to take to lower their risk of future infection

Neutralization Tests - immune testing

- immune test that measures the ability of antibodies to neutralize the biological activity of pathogens and toxins

Contact Immunity (2)

- immunity beyond the individual receiving the vaccine - occurs when a newly vaccinated person infects another person

BCR

- immunoglobulin made of 6 polypeptide chains - 2 identical, long heavy chains and 2 identical, short light chains form two arms that extend outside the cell - 2 additional chains anchor the BCR into the membrane (transmembrane portion)

Memory (3)

- immunological memory for specific pathogens --> adapts to respond faster and more effectively in subsequent encounters with a particular type of pathogen or toxin - innate does NOT do this

How is lupus treated? (2)

- immunosuppressive drugs that reduce autoantibody formation - glucocorticoids that reduce the inflammation associated with the deposition of immune complexes

Naturally Acquired Passive Immunity (4)

- in the womb, IgG molecules cross the placenta from the mother's bloodstream - children receive secretory IgA in breast milk - a mother provides her baby with antibodies that protect it during its early months - baby is not actively producing its own antibodies

Minor Polio - polio conditions

- includes nonspecific symptoms such as temporary fever, headache, malaise, and sore throat. - 5% of all cases

Attenuated viruses in a attenuated vaccine (2)

- infect host cells and replicate - infected cells then process endogenous viral antigens

Epidemiology of Warts (papillomaviruses) (4)

- infect the skin through cuts or abrasions - transmitted via direct contact, including childbirth and sexually - transmitted via fomites too because they are stable outside the body - autoinoculation: patients can spread wart viruses from one location to another on their own bodies

Pityriasis versicolor - Superficial Mycoses (4)

- infection of Malassezia furfur - characterized by hypopigmented or hyperpigmented patches of scaly skin resulting from fungal interference with melanin production - typically occurs on the trunk, shoulders, and arms, and rarely on the face and neck - called versicolor in reference to the variable pigmentation seen in affected individuals

Folliculitis - Skin Disease (7)

- infection of a hair follicle - AKA "pimple" --> base of the follicle becomes red, swollen, and pus filled - AKA "sty" when it occurs at the eyelid base - "furuncle" or "boil" is a large, painful, raised nodular extension of folliculitis resulting from spread of the infection into surrounding tissues --> "carbuncle" when several furuncles join together, often in thick skin like back of the neck - when severe, body triggers fever

Prion

- infectious protein - Prions exist in one of two three-dimensional forms: -- normal form is anchored in lipid rafts in membranes of neurons of the CNS and is necessary for normal brain function -- abnormal prion acts as an enzyme to refold the normal form into a copy of the abnormal form --> Newly misfolded prions then proceed to make copies of themselves from surrounding normal prion molecules --> abnormal prions turn normal prion proteins into abnormal prions, which continue the process

Pneumonia

- inflammation of the lungs in which the alveoli and bronchioles become filled with fluid - typically caused by infection with Streptococcus pneumoniae - In some patients, this fluid is pus: a condition known as empyema

Bacterial gastroenteritis

- inflammation of the stomach or intestines caused by the presence of bacteria - associated with poorly prepared foods, contaminated washing or drinking water, and communities with poor living conditions General features - Similar manifestations despite different causative agents - Nausea, vomiting, diarrhea, abdominal pain, and cramps - Dysentery produces loose, frequent stool containing mucus and blood - diagnosed by s/s - ID bacterium form stool samples or from suspected food - replace fluids and electrolytes

Epidemiology of Herpes Infections (7)

- initial infections with herpesviruses are usually age specific --> Primary HHV-1 infections typically occur via casual contact during childhood and produce no signs or symptoms --> Most HHV-2 infections, by contrast, are acquired between the ages of 15 and 29 as a result of sexual activity, including oral sex - Whitlow is a hazard for children who suck their thumbs, for patients with genital herpes, and especially for health care workers in the fields of obstetrics, respiratory care, gynecology, and dentistry who come into contact with herpes lesions. - Spread between mucous membranes of mouth and genitals - Herpes infections in adults are not life threatening - Neonatal infections can be fatal

Attenuated (Modified Live) Vaccines - Types of Vaccines (6)

- inoculum in which pathogens are weakened so that, theoretically, they can no longer cause disease - residual virulence can be a problem in immunosuppressed people - contain active but generally avirulent microbes --> cause very mild infections but no serious disease under normal conditions - Because modified live vaccines contain active microbes, a large number of antigen molecules are available --> elicit vigorous antibody and cell-mediated immune responses

Virulence Factors of Chickenpox and Shingles (2)

- intracellular infection - ability to lie dormant within nerve cells for years

Does the body use cell-mediated immune responses to fight intracellular OR extracellular pathogens? (4)

- intracellular pathogens! - abnormal body cells (cancer) - intracellular parasitic protozoa - intracellular bacteria

Bacterial Meningitis

- involves inflammatory bacterial infection of the meninges, commonly the pia mater and arachnoid mater and, more rarely, the dura mater - Sudden high fever, severe headache, stiff neck, increased number of white blood cells in the CSF, intense meningeal inflammation --> inflammation accounts for most of the signs and symptoms: Swelling of the meninges retards the normal flow of CSF, putting pressure on the underlying organs --> Inflammation of the cranial meninges typically produces severe headache, nausea, vomiting, pain, and in many cases loss of various brain functions, leading to such conditions as drowsiness, confusion, fretfulness, or irritability --> Inflammation of the spinal meninges puts pressure on surrounding nerves and muscles, producing stiffness in the neck and affecting sensory input and muscular control - Encephalitis (brain infection) can result in blindness, deafness, behavioral changes, coma, and death - Can develop rapidly; can kill within 6 hrs of symptoms

Signs and Symptoms of bacterial intoxications (toxifications) (food poisoning)

- may range from mild to severe - may differ depending on the toxins present - can be confused with bacterial or viral gastroenteritis - nausea, vomiting, diarrhea, abdominal cramping, discomfort, bloating, loss of appetite, and fever - Some types of intoxications also produce weakness, headache, and difficulty in breathing - Dehydration resulting from fluid loss in diarrhea may become significant, but most cases, exemplified by staphylococcal food poisoning, are self-limiting and last no more than 24 hours

Malaria

- mild to potentially fatal disease caused by a bite from an Anopheles mosquito carrying any of four species of Plasmodium; characterized by fever, chills, hemorrhage, and potential destruction of brain tissue - Plasmodium is an apicomplexan which is a type of protozoan characterized by a form of asexual reproduction called schizogony --> In schizogony, the nucleus of a cell undergoes successive mitoses without cytoplasmic division, forming multinucleate cells called schizonts --> Eventually, a schizont divides to simultaneously form several offspring, each with a single nucleus

antibody sandwich ELISA - labeled immunoassay

- modification of the ELISA technique - can be used to detect antigen (direct testing) - used to quantify the amount of an antigen in a given sample, and they can be used to test for illegal drugs

Pathogen and Virulence Factors of Zika Virus

- mosquito-borne, enveloped, unsegmented, +ssRNA flavivirus with an icosahedral capsid - virus preferentially replicates in brain cells

Humoral Immune Response (3)

- mounted against exogenous pathogens and toxins - Activates only in response to specific epitopes - 2 types (T-dependent; T-independent)

Secondary Response (4)

- much faster and more effective than the primary response --> Because many memory cells recognize and respond to the antigen - subsequent exposure directly stimulates a population of memory cells, which proliferate and differentiate rapidly into plasma cells without having to be activated by antigen-presenting cells - Newly differentiated plasma cells produce large amounts of antibody within a few days

Diagnosis, Treatment, and Prevention of Primary Atypical (Mycoplasmal) Pneumonia

- mycoplasmas are so small that they're difficult to detect in samples - cultures take 2-6 weeks to grow - Complement fixation, hemagglutination, and immunofluorescent tests confirm a diagnosis, but such tests are nonspecific and are not by themselves diagnostic - treat primary atypical pneumonia with antimicrobials such as erythromycin or doxycycline - Prevention is difficult because patients are often infective for long periods without signs or symptoms, and they remain infective even while undergoing antimicrobial treatment - frequent handwashing, avoidance of contaminated fomites, and reducing aerosol dispersion - NO VACCINE

Peripheral Nervous System Components

- nerve plexus - spinal ganglion - mixed spinal nerve - *composed of nerves that transfer commands from the CNS to muscles and glands throughout the body and provide information to the CNS concerning events in the body - Cranial nerves extend from the brain through holes in the cranial bones - spinal nerves extend from the spinal cord through gaps between vertebrae - Sensory nerves primarily carry signals toward the CNS (optic nerves) - Motor nerves carry signals from the CNS to other organs of the body - mixed nerves carry signals both toward and away from the CNS

Inflammation (3)

- nonspecific response to tissue damage (heat, chems, UV sunburn, abrasions, cuts, pathogens) - Characterized by redness, heat, swelling, and pain - 2 types (acute & chronic)

Epidemiology of Staphylococcus aureus for Folliculitis (5)

- not a permanent resident; transient --> does grow on the skin or mucous membranes of most people at some time in their lives, particularly in the nostrils --> a fifth of the population carries the bacterium with no symptoms for a year or more - also intermittently colonizes moist skin folds such as in the armpits and around the groin --> often being transferred from the face via the hand

Two types of fingerlike cytoplasmic processes extend from a cell body:

- numerous, perhaps hundreds, of short dendrites - long, single axon

Glomerulonephritis - localized Type 3 (5)

- occurs when immune complexes circulating in the bloodstream are deposited in the walls of glomeruli, which are networks of minute blood vessels in the kidneys - Immune complexes damage the glomerular cells, leading to enhanced local production of cytokines that trigger nearby cells to produce more of the proteins that underlie the cells, impeding blood filtration - Sometimes, the immune complexes are deposited in the center of the glomeruli, where they stimulate local cells to divide and compress nearby blood vessels, again interfering with kidney function - net result is kidney failure; the glomeruli lose their ability to filter wastes from the blood, ultimately resulting in death - typically caused by infection with group A Streptococcus (GAS)

primary amebic meningoencephalopathy

- often fatal inflammation of the brain characterized by headache, vomiting, fever, and destruction of neurological tissue - caused by infection with Naegleria OR Acanthamoeba - signs same as meningitis or encephalitis caused by bacteria, viruses, or fungi --> headache, fever, stiff neck, altered mental state, and vomiting - Symptoms progressively worsen over a period of three to seven days until the patient dies

Neisseria meningitidis - pathogen of bacterial meningitis

- one of only two species of Gram-negative cocci that regularly causes disease in humans - 13 antigenic strains; strains A, B, C, and W135 cause most cases of disease in humans - nonmotile - diplococci (pairs) with their common sides flattened in a manner reminiscent of coffee beans - The bacterium is known as the meningococcus and its disease as meningococcal meningitis - fimbriae and polysaccharide capsules, as well as a major cell wall antigen called lipooligosaccharide , composed of lipid A (the toxic part of lipopolysaccharide, which is also known as endotoxin) and sugar molecules—all of which enable the bacteria to attach to human cells --> Cells of Neisseria that lack any of these three structural features are avirulent - polysaccharide capsules also resist lytic enzymes of the body's phagocytes, allowing phagocytized meningococci to survive, reproduce, and be carried throughout the body within neutrophils and macrophages - blebbing—a process in which the bacterium sheds extrusions of its outer membrane --> lipid A component of LOS thereby released into the body triggers fever, vasodilation, inflammation, shock, and widespread blood clotting

Processing Exogenous Antigens

- only APCs (usually dendritic cells) process exogenous antigens 1. dendritic cell phagocytizes an invading pathogen and clips the proteins into segments, producing peptide epitopes within a phagolysosome 2. Another vesicle, already containing MHC class II molecules in its membrane, fuses with the phagolysosome. MHC II molecules bind complementary epitopes 3. vesicle then fuses with the cytoplasmic membrane 4. results in MHC II-epitope complexes on the cell's surface 5. Empty MHC II molecules (those not bound to epitopes) are not stable on a cell's surface; they degrade.

Mycoses (3)

- opportunistic fungal disease - traditionally classified according to the locations within the body that they affect --> superficial (on the surface), cutaneous (in the skin), subcutaneous (in the hypodermis and muscles), or systemic (affecting numerous systems)

Schistosomiasis

- parasitic blood flukes of the genus Schistosoma are one of the more common parasitic helminths of humans in the world - a potentially fatal disease and one of the major public health problems in the world - may cause tissue damage in the liver, lungs, brain, or other organs - A transient dermatitis called swimmer's itch may occur in the area where infective larvae burrow into the skin - larvae migrate throughout the body via the vascular system; such migration produces no signs or symptoms - when the worms mature and mate, infections become dangerous as eggs lodge in the liver, lungs, brain, kidneys, and other organs - Trapped eggs die and calcify, leading to renal failure, splenomegaly, increased blood pressure in the pulmonary circulation, or heart failure - death can result - In some infections, movement of eggs into the bladder and ureters (tubes draining the kidneys into the bladder) causes bladder obstruction and bloody urine and has been tied to fatal bladder cancer

Foodborne Botulism

- patients become weak and dizzy one to two days following the consumption of botulism toxin in contaminated food, which may not appear or smell spoiled - Blurred vision with fixed dilated pupils, dry mouth, constipation, nausea, vomiting, and pain may also occur - Progressive paralysis of all voluntary (skeletal) muscles then begins on both sides of the body as peripheral nerves are affected - patient remains mentally alert - Death, if it occurs, is from paralysis of the diaphragm - Survivors recover very slowly as their nerve cells grow new endings over the course of months or years, replacing their nonfunctioning tips

lepromatous leprosy

- patients with a weak T cell immune response - signs and symptoms may take years to show (progressive tissue destruction) - the bacterium multiplies in skin and mucous membranes as well as nerve cells, gradually destroying tissue and leading to the progressive loss of facial features, digits (fingers and toes), and other body structures - death is rare and usually results from the infection of leprous lesions by other pathogens

Treatment of Necrotizing Fasciitis (4)

- physicians must remove dead tissue immediately, repeating the procedure daily until bacterial destruction of tissue is halted - intravenous broad-spectrum antimicrobial drugs to curb the severity of disease and inhibit any remaining bacteria --> IV combination of vancomycin, clindamycin, and/or penicillin if suspected or confirmed --> clindamycin and penicillin when used together had a cure rate of 83%, compared to a cure rate of only 41% for penicillin alone

Complications of Measles (5)

- pneumonia - encephalitis - otitis media (middle ear infection) - deafness - blindness - subacute sclerosing panencephalitis (SSPE)

Type I hypersensitivity site of LOCAL reaction depends on: (2)

- portal of entry - Small inhaled allergens may reach lungs and cause asthma

Necrotizing Fasciitis (5)

- potentially fatal condition marked by toxemia, organ failure, and destruction of muscle and fat tissue following infection with group A Streptococcus (GAS) - Redness, intense pain, and swelling at infection site --> patients initially report a hot, intensely painful, sunburn-like rash at the site of infection - As tissue is destroyed, blood pressure drops, and patients become mentally confused and ultimately comatose - Develop fever, nausea, malaise, and possible mental confusion

African trypanosomiasis

- potentially fatal disease caused by a bite from a tsetse fly carrying Trypanosoma brucei and characterized by formation of a lesion at the site of the bite, followed by cyclical waves of parasitemia and central nervous system invasion - PROGRESSED THROUGH 3 CLINICAL STAGES

Cellulitis (4)

- potentially life-threatening bacterial infection of the deeper dermis and subcutaneous fa - appears as a red, swollen area that feels hot and is tender to the touch - Like erysipelas, cellulitis typically occurs on only one side of the body - unlike erysipelas, cellulitis does not involve lymphatic tissue, and the margins of the inflamed tissue are not well defined - GAS causes most cases

Kinins (2)

- powerful inflammatory chemicals released by mast cells - Cause smooth muscle contraction, inflammation, and irritation

serological methods (6)

- precipitations - turbidimetry - nephelometry - agglutination - neutralization - labeled immunoassays

Common Immunochromatographic assays

- pregnancy testing, which tests for human chorionic gonadotropin—a hormone produced only by an embryo, fetus, or placenta - rapid identification of infectious agents such as HIV, Escherichia coli O157:H7, group A Streptococcus, respiratory syncytial virus (RSV), and influenzaviruses

Rh antigen (4)

- present on the red blood cells of about 85% of humans (Rh+) - preexisting antibodies against Rh antigen do not occur - Rh reactions are usually minor because Rh antigen molecules are less abundant than A or B antigens - primary problem posed by incompatible Rh antigen is the risk of Hemolytic disease of the newborn

HIV-2 (3)

- prevalent in West Africa - shares about 50% of the nucleic acid sequence of HIV-1 - reproduces more slowly than HIV-1

self-tolerance (2)

- prevents the body from mounting an immune response against itself - immune cells that treat autoantigens as if they were foreign are normally eliminated during the development of the immune system

Epidemiology of Staphylococcal Scalded Skin Syndrome (SSSS) (3)

- primarily a disease of infants and children under age five - can also affect the elderly and immunosuppressed patients, such as those with AIDS --> antibodies apparently protect people with well-developed immune systems

Antigen-Presenting Cells (APCs) (4)

- process antigens and activate cells of the immune system - includes: B lymphocytes, macrophages, dendritic cells - "Professional" antigen-presenting cells regularly present antigens --> specialize in presenting antigen to T cells

Attenuation (3)

- process of reducing pathogen virulence for vaccines - culture viruses for generations within inhospitable environments; they an lose the ability to produce disease in humans as they adapt - bacteria virulence is reducing by culturing them under unusual conditions or by using genetic manipulation

Antiviral Proteins (AVPs) (6)

- produced by IFNs binding to viral-infected cell cyto-membranes - remain inactive within these cells until AVPs encounter viral nucleic acids (helix RNA) (common in viruses, absent in Euk) - oligoadenylate synthetase destroys RNA - protein kinase R inhibits protein synthesis by ribosomes - AVPs destroy the protein production system of the cell, preventing viruses from being replicated (cell metabolism IS affected) - antiviral state lasts 3-4 days

Type II (Gamma) Interferons (4)

- produced by active T lymphocytes and NK lymphocytes - appear later (bc T lymph are activated in adaptive response days after infection start) - AKA "macrophage activation factor" - regulates the immune system by activating phagocytic activity

Endogenous Antigens (4)

- produced by intracellular microbes and are typically incorporated into a host cell's cytoplasmic membrane - Protozoa, fungi, bacteria, and viruses that reproduce inside a body's cells - immune system cannot assess the internal health of the body's cells --> responds to endogenous antigens only if the body's cells incorporate such antigens into their cytoplasmic membranes, leading to their external display

pneumonic plague

- produced by the bubonic plague bacillus, Yersinia pesti - Fever, chills, cough, difficulty breathing, and frothy bloody sputum - bacterium can enter the lungs in respiratory droplets or via the blood and can cause pneumonia in just a few hours - mortality is reduced to about 5% with treatment with streptomycin or gentamicin

Campylobacter Diarrhea

- responsible for more cases of diarrhea that send people to doctors in the United States than any other bacterium - Campylobacter jejuni --> Gram-negative, slightly curved bacterium with polar flagella --> adhesins, cytotoxins, and endotoxin - study found Campylobacter in 81% of chickens, which are the primary source of human infections - The virulence factors of Campylobacter enable colonization and invasion of the jejunum, ileum, and colon, producing bleeding lesions and triggering inflammation - Campylobacter infections sometimes trigger long-term consequences, such as arthritis or irritable bowel syndrome (IBS) --> 1/1000 cases leads to Guillain-Barre syndrome --> rare autoimmune disorder that damages nerves, resulting in muscle weakness and sometimes paralysis that can last for a few weeks or even for several years - Toxin A mediates inflammation and toxin B kills colon cells producing lesions pseudomembrane formation

DiGeorge syndrome - Primary Immunodeficiency Diseases (5)

- results from a failure of the thymus to develop --> no T cells are created - patients generally die of viral infections while remaining resistant to most bacteria --> phenomenon that underscores the importance of T cells in protecting against viruses - treat DiGeorge syndrome with a thymic stem cell transplant

Diagnosis, Treatment, and Prevention of Campylobacter Diarrhea

- s/s combined with bacteria in xTAG GPP analysis of stool - severe cases require supportive therapy and the use of antimicrobial drugs such as erythromycin - no vaccine

Viral Neutralization (4)

- serum is tested for antibodies against a particular virus in which test serum is mixed with the virus, and then the mixture is added to a cell culture - cell survival indicates that the antibodies in the serum have neutralized the viruses - can identify viruses --> Viral neutralization tests are sufficiently sensitive and specific to ascertain whether an individual has been exposed to a particular virus or viral strain, which may lead a physician to a diagnosis or treatment or to recommendations to prevent future infection or disease

C. diff. (Antimicrobial-Associated) Diarrhea

- severe form of diarrhea, which is often accompanied by intense inflammation and formation of lesions in the colon, frequently develops in hospitalized patients taking antimicrobial drugs - ranges from 5 to 10 clear, watery, foul-smelling bowel movements per day to a most severe form of intestinal disease called Pseudomembranous colitis - Clostridioides difficile --> Gram-positive, endospore-forming, anaerobic bacillus is part of the normal microbiome of the large intestine - when antimicrobials kill the good bacteria, C. difficile endospores germinate and reproduce out of control, presumably because they have no competition - toxins A & B

Shigellosis

- severe form of dysentery - characterized primarily by fever, abdominal cramps, diarrhea, and sometimes a bloody stool - shigella; 4 types --> Gram-negative, nonmotile bacillus --> S. dysenteriae (produces shiga toxin, causes dysentary), S. flexneri (developing countries), S. boydii, and S. sonnei (in industrialized nations) (most common) - produce type III secretion systems and diarrhea-producing enterotoxins - insert into a host cell's cytoplasmic membrane, forming a channel through which bacterial proteins are introduced into the host cell - bind to surface proteins on epithelial cells lining the intestines, triggering the loss of electrolytes and water - S. dysenteriae secretes Shiga toxin, which is an exotoxin that stops protein synthesis in a host's cells, resulting in a more severe form of shigellosis with a mortality rate as high as 20%

Dysentery

- severe gastroenteritis - characterized by severe diarrhea, often with loose stools containing blood and mucus

One classic feature of hemolytic disease of the newborn (3)

- severe jaundice from excessive bilirubin, which is a yellowish blood pigment released during the degradation of hemoglobin from lysed red blood cells - liver is normally responsible for removing bilirubin - because of the immaturity of the fetal liver and overload from the hemolytic process, the bilirubin may instead be deposited in the brain, causing severe neurological damage or death during the last weeks of pregnancy or shortly after the baby's birth

Diagnosis, Treatment, and Prevention of Respiratory syncytial virus (RSV) infection

- signs of respiratory distress provide some diagnostic clues, but verification of RSV infection is made by immunoassay - Specimens of respiratory fluid may be tested by immunofluorescence, ELISA, or complementary nucleic acid probes - For younger children, supportive treatment includes administration of oxygen, intravenous fluids, drugs to reduce fever, and antibiotics to reduce secondary bacterial infections - Immunoglobulins against RSV, derived from blood donations, have proven effective for treating severe cases - Ribavirin via inhalation in mist form is used to treat extreme cases in premature and immunocompromised infants - Older children and most adults require no treatment because their disease is mild - Control of RSV is limited to attempts to delay infection of susceptible infants through proper aseptic techniques - NO vaccine because the vaccine enhances the severity of the cellular immune response and lung damage

Lymph Nodes (4)

- sites to facilitate interactions among immune cells and between immune cells and material arriving at lymph nodes from throughout the body - afferent vessels inbound - efferent vessels outbound - concentrated in the cervical (neck), inguinal (groin), axillary (armpit), and abdominal regions

Scabies (5)

- skin disease caused by a burrowing mite arachnid - Characterized by intense itching and rash at infection site (ESPECIALLY AT NIGHT??) - rash appears as pimple-like irritations or short, slightly raised burrows under the surface of the skin - Lesions common between the fingers; around the genitalia; and on the wrists, elbows, and knees - Scratching often compounds the symptoms by introducing Staphylococcus or Streptococcus into the wounds, which triggers bacterial infections, including impetigo

potential causes of autoimmune hemolytic anemia (2)

- some cases follow infections with viruses or treatment with certain drugs - both of which alter the surface of red blood cells such that they are recognized as foreign and trigger an immune response

Epidemiology of Rubella (3)

- spreads through respiratory secretions and infects humans only - Patients shed virions (complete virus particles) in respiratory droplets for approximately two weeks before and two weeks after the rash - The most severe form of rubella is in a fetus under 20 weeks old

Histamine (4)

- stimulates strong contractions in the smooth muscles of the bronchi, gastrointestinal tract, uterus, and bladder, and it also makes small blood vessels dilate (expand) and become leaky - stimulates nerve endings, causing itching and pain - stimulator of bronchial mucus secretion, tear formation, and salivation - tissues in which mast cells degranulate become red and swollen

Antibody-Epitope bond (2)

- strong, highly specific, noncovalent interaction - hydrogen bonds and other molecular attractions mediate antibody binding to epitope

Treatment of Chickenpox and Shingles (3)

- supportive therapy and antiviral drug ayclovir or its derivatives - symptoms may be treated with acetaminophen and/or antihistamines - aspirin should never be given to children with viral infections

Diagnosis of Folliculitis (4)

- the detection of Gram-positive bacteria in grapelike arrangements isolated from pus - If staphylococci isolated from an infection are able to clot blood, then they are coagulase-positive S. aureus - Coagulase-negative staphylococcus is usually S. epidermidis --> its presence in a clinical sample is not normally indicative of staphylococcal disease

Smallpox (Variola virus) (3)

- the first human disease eradicated (declared in 1980) - Edward Jenner first demonstrated immunization using the relatively mild cowpox virus to protect against smallpox --> antigens of cowpox virus are chemically similar to those of smallpox virus, so that exposure to cowpox results in immunological memory and subsequent resistance to both cowpox and smallpox

Systemic Lupus Erythematosus (SLE) - systemic Type 3 (8)

- the individual produces autoantibodies against numerous antigens, including nucleic acids (esp DNA) --> autoantibodies combine with free DNA released from dead cells to form immune complexes that are deposited in glomeruli, causing glomerulonephritis and kidney failure --> Immune complexes may also be deposited in joints, where they give rise to arthritis - immune system attacks multiple organs, giving rise to many different pathological lesions and clinical manifestations - characteristic red, butterfly-shaped rash that develops on the face of many patients --> caused by deposition of nucleic acid-antibody complexes in the skin and is worse in skin areas exposed to sunlight - due to its variety of symptoms, SLE can be misdiagnosed - trigger unknown; some drugs can induce a lupus-like disease; likely has many causes

clinical manifestations of leishmaniasis depend on: (3)

- the species of pathogen - the geographical location of hosts and vectors - the immune response of the infected host

How do these chemicals make venules more permeable? (4)

- they cause cells lining the vessels to contract and pull apart, leaving gaps in the walls through which phagocytes can move into the damaged tissue and fight invaders - Increased permeability also allows delivery of more bloodborne antimicrobial chemicals to the site - fluid leaking from these gaps caused edema --> puts pressure on nerve endings, producing much of the pain of inflammation

Hybridomas (6)

- tumor cells created by fusing antibody-secreting plasma cells with cancerous plasma cells called Myelomas - divides continuously as clones "monoclonal antibodies" - each clone secretes large amounts of a single antibody molecule - maintained in tissue culture to produce the antibodies needed for passive immunotherapy - Hybridomas made with cells from these mice secrete antibodies identical to those of humans, eliminating rejection - Ex. physicians use such a monoclonal antibody to treat newborns infected with respiratory syncytial virus

cytokines - Potential effects of endotoxin

- tumor necrosis factor (TNF) --> causes tissue damage and is pyrogenic (produces fever) - interleukins (ILs) --> immue system cytokines that signal among leukocytes --> IL-1 also triggers fever and causes the bone marrow to release a large number of immature neutrophils, which attach to and damage blood vessel walls. IL-6 and IL-8 damage circulating neutrophils and further injure cells lining blood vessels, allowing plasma to escape the vascular system, precipitously reducing blood pressure. The drop in blood pressure reduces blood flow and oxygen delivery to vital organs, which can succumb, resulting in death - platelet activating factor (PAF) --> a potent trigger for blood coagulation

autoimmune hemolytic anemia - Single-Organ Autoimmune Diseases (6)

- type 2 hypersensitivity - produce antibodies against their own red blood cells --> speed up the destruction of the red blood cells; patient is severely anemic - IgM autoantibodies, which bind to red blood cells and activate the classical complement pathway; the red blood cells are lysed, and degradation products from hemoglobin are released into the bloodstream - IgG autoantibodies, which serve as opsonins that promote phagocytosis. In this case, red blood cells are removed by macrophages in the liver, spleen, and bone marrow --> these latter patients have no hemoglobin in their urine, they are still severely anemic

Type 1 Diabetes Mellitus - Single-Organ Autoimmune Diseases (5)

- type 4 hypersensitivity - autoimmunity against endocrine organs - Immunological attack on the islets of Langerhans results in a loss of the ability to produce the hormone insulin - could follow severe viral infection - could be genetic predisposition associated with the possession of certain class I MHC molecules

Multiple Sclerosis - Single-Organ Autoimmune Diseases

- type 4 hypersensitivity - possible cause: a cell-mediated immune response against a bacterium or virus generates cytotoxic T cells that mistakenly attack and destroy the myelin sheaths that normally insulate brain and spinal cord neurons and increase the speed of nerve impulses along the length of the neurons --> Consequently, MS patients experience deficits in vision, speech, and neuromuscular function that may be quite mild and intermittent or may be progressive, paralytic, and perhaps fatal

Structure of HIV-1 (6)

- typical retrovirus in shape, components, and size - Two antigenic glycoproteins characterize its envelope - The larger glycoprotein, named gp120 is the primary attachment molecule of HIV --> its antigenicity changes during the course of prolonged infection, making it difficult for the body to make an effective antibody response against gp120 - smaller glycoprotein, gp41, promotes fusion of the viral envelope with the cytoplasmic membrane of a CD4+ cell - The effects of these structural characteristics—antigenic variability and the ability to fuse with host cells—interfere with clearance of HIV from a patient.

Physicians diagnose AIDS on the basis of:

- unexplained weight loss - fatigue - fever - fewer than 200 CD4+ lymphocytes per microliter (μl) of blood - the demonstration of antibodies against HIV - combined with other signs and symptoms, which vary according to the diseases involved.

Diagnosis, Treatment, and Prevention of Rubella (4)

- usually diagnosed by observation of rash, which is confirmed by serological testing for IgM against rubella - No treatment is available, but immunization has proven effective at reducing the incidence of rubella in industrialized countries - immunization is aimed at reducing the number of rubella cases that might serve to introduce rubella to pregnant women - Rubella vaccine (combined with vaccine against measles and mumps as MMR) is made from a live, weakened virus and therefore should never be given to pregnant women or immunocompromised patients

Vaccine Safety - Problems associated with immunization (7)

- vaccines containing adjuvant may cause injection-site pain - Mild toxicity --> rarely, toxicity may result in general malaise and possibly a fever high enough to induce seizures - Risk of anaphylactic shock (severe allergic reaction) (egg proteins, adjuvants, or preservatives) - Residual virulence from attenuated viruses - Allegations that certain vaccines cause autism, diabetes, and asthma --> Research has not substantiated these allegations

Adaptive Immunity

- vertebrate's ability to recognize and then mount a defense against specific invaders and their products

Paralytic Polio - polio conditions

- viral invasion of cells of the spinal cord and the portion of the cerebrum that controls skeletal muscles - paralysis by limiting nerve impulse conduction --> produces complete paralysis that may or may not reverse - degree of paralysis varies with the strain of poliovirus involved, the infective dose, and the health and age of the patient

Mycobacteria

-- Grow slowly (in part because of the time required to synthesize numerous molecules of mycolic acid). The generation time varies from hours to several days. -- Are protected from lysis once they are phagocytized. -- Are capable of intracellular growth. -- Are resistant to Gram staining, detergents, many common antimicrobial drugs, and drying out. Because mycobacteria stain only weakly with the Gram procedure (if at all), the acid-fast staining procedure was developed to stain them

Virulence Factors of Streptococcal Respiratory Diseases - BOOK

-- M protein causes inhibition of complement component C3b, thereby interfering with opsonization and lysis -- The hyaluronic acid capsule may "camouflage" the bacterium from phagocytes. -- Streptokinases are enzymes that break down blood clots, presumably enabling group A streptococci to spread rapidly through damaged tissues. -- C5a peptidase is an enzyme that breaks down complement protein C5a, which is a chemotactic factor. With this enzyme, S. pyogenes decreases the movement of leukocytes into the site of infection. -- Pyrogenic toxins (also called erythrogenic toxins) stimulate leukocytes to release cytokines that in turn stimulate fever, rash, and shock. -- Streptolysin O lyses human cells such as erythrocytes, leukocytes, and platelets.

4 toxins of Pertussis (Whooping Cough)

-- Pertussis toxin, an AB toxin that interferes with ciliated epithelial cells' metabolism, resulting in increased mucus production. (Note that pertussis toxin is both an adhesin and a toxin.) -- Adenylate cyclase toxin, which triggers increased mucus production and inhibits leukocyte movement, phagocytosis, and killing. -- Dermonecrotic toxin, which causes localized constriction and hemorrhage of blood vessels, resulting in cell death and tissue destruction. -- Tracheal cytotoxin, which at low concentrations inhibits the movement of cilia on respiratory cells.

Genetic Traits that Increase Resistance to Malaria

-- Sickle-cell trait. Individuals with a sickle-cell gene produce an abnormal type of hemoglobin called hemoglobin S (hemoglobin A is normal). Hemoglobin S causes erythrocytes to become sickle shaped and makes erythrocytes resist Plasmodium. -- Hemoglobin C. Humans with two genes for hemoglobin C are invulnerable to malaria. The mechanism by which this mutation provides protection is unknown. -- Genetic deficiency of glucose-6-phosphate dehydrogenase. In order to synthesize DNA, trophozoites must acquire this enzyme from their human host; thus, inherited enzyme deficiency inhibits Plasmodium replication. -- Lack of so-called Duffy antigens on erythrocytes. Because P. vivax attaches to Duffy antigens to infect erythrocytes, Duffy-negative individuals are resistant to P. vivax.

Unusual Cell Walls of Mycobacterium lepraeis - pathogen of Hansen's Disease

-- Slow growth rate (due to the time required to synthesize numerous molecules of mycolic acid). Cellular generation time varies from hours to several days. -- Protection from lysis once the bacteria are phagocytized. -- Growth within phagocytes. -- Resistance to Gram staining, detergents, many common antimicrobial drugs, and drying. Because mycobacteria Gram stain only weakly, the acid-fast staining procedure was developed to differentially stain mycobacteria

Virulence factors of Plasmodium - Malaria

-- The reproductive cycle occurs within red blood cells, which hides the parasite from the immune surveillance since red blood cells do not present antigen in conjunction with major histocompatibility protein. -- A special protein assemblage called the malaria secretome injects toxins and enzymes into host cells. -- Adhesins enable infected red blood cells to adhere to certain body tissues such as brain tissue and the linings of blood vessels, which allows the parasite to avoid clearance by the spleen. -- Merozoites form within vesicles of liver cells that are secreted directly into blood vessels, thereby avoiding immune cells of the liver. -- The gametocytes of at least one strain (P. falciparum) trigger changes in human body chemistry, presumably breath or body odor, such that Anopheles mosquitoes are more attracted; thus Plasmodium induces a "bite me" signal in humans carrying the very stage ready to be picked up by a mosquito.

Problems to Overcome Creating and HIV Vaccine

--- A vaccine must generate both cell-mediated immunity (so that cytotoxic T lymphocytes would be able to eliminate infected cells) and antibody immunity (especially secretory antibody [IgA], whose presence in mucus would reduce sexual transmission of the virus). --- Induction of synthesis of gamma class antibodies (IgG), a necessary function of a vaccine, can actually be detrimental to a patient. Because IgG-HIV complexes bind to B cells and also remain infective inside phagocytic cells, a vaccine must stimulate cell-mediated immune response more than antibody immune response so as to kill infected cells. --- HIV is highly mutable, generating antigenic variants that enable it to evade the immune response. Scientists estimate the diversity of HIV sequences found in one person at any one time is greater than the diversity of flu viruses in everyone worldwide during a full year. --- HIV can spread directly from cell to cell because gp41 remains on an infected cell's cytoplasmic membrane after HIV has entered. Glycoprotein 41 can fuse the HIV-infected cell to neighboring cells, allowing HIV access to the neighbor and enabling it to evade some immune surveillance. - HIV infects and inactivates macrophages, dendritic cells, and helper T cells—cells that combat infections. --- Testing a vaccine presents ethical and medical problems because HIV is a pathogen of humans only. For example, researchers stopped a study in 1994 when HIV infected five volunteers despite their having received an experimental vaccine

Pathogenesis and epidemiology of coronaviruses

-Coronavirus spreads via respiratory droplets --> Face masks/coverings prevent spread of respiratory droplets and can slow epidemics -Binds to lung cells, causes death and triggering the respiratory symptoms. Then spreads via blood to the heart and kidneys. -SARS mortality ~10%; MERS mortality ~35%

Diagnosis, treatment, and prevention of coronaviruses

-Diagnosis based on signs and symptoms -Confirmed by isolating the virus or antibodies against the virus -Treatment is supportive

Lyme Disease Signs and Symptoms - 3 Phases

1) Bull's-eye rash at infection site --> occurs at the site of infection within 3-30 days --> Other early signs and symptoms include malaise, headaches, dizziness, stiff neck, severe fatigue, fever, chills, muscle and joint pain, and lymphadenopathy 2) Neurological symptoms: stiff neck, headache, facial paralysis, numbness, pain, memory loss, personality changes, difficulty concentrating 3) Severe arthritis: in 80% of patients, 20% will have lifetime arthritis --> the latter phases of Lyme disease are due in large part to the body's immunological response

Steps of T-dependent antibody response (LONG)

1. Antigen presentation for Th activation and proliferation - Antigen presentation, in which an APC, typically a dendritic cell, presents antigen to a complementary Th cell - Antigen presentation depends on chance encounters between Th cells and the dendritic cells - Once they have established an immunological synapse, CD4 molecules in membrane rafts of the Th cell's cytoplasmic membrane recognize and bind to MHC II, stabilizing the synapse - a second signal helps prevent accidental inducement of an immune response - APC imparts the second signal by displaying an integral membrane protein in the immunological synapse. This induces the Th cell to proliferate, producing clones 2. Differentiation of helper T cells into Th2 cells - the cytokine interleukin 4 (IL-4) acts as a signal to the Th cells to become type 2 helper T cells (Th2 cells) 3. Activation of B cells - A Th2 cell binds to the B cell with an MHC II protein-epitope complex that is complementary to the TCR of the Th2 cell. - CD4 glycoprotein again stabilizes the immunological synapse - Th2 cells secrete more IL-4, which induces the selected B cell to move to the cortex of the lymph node - Th2 cell in contact with an MHC II protein-epitope on the B cell is stimulated, expresses new gene products, and inserts a protein called CD40L into its cytoplasmic membrane - CD40L binds to CD40, which is found on B cells triggering Clonal Selection 4. Proliferation and Differentiation of B Cells - memory B cells - antibody-secreting plasma cells

5 mechanism steps of type III (immune complex-mediated) hypersensitivity

1. Antigens combine w/ antibodies (IgG) to form antigen-antibody complexes (immune complexes) 2. Phagocytes remove most of the complexes, but some lodge in the walls of blood vessels 3. There, the immune complexes activate complement 4. Immune complexes and activated complement attract and activate neutrophils, which release enzymes 5. Enzymes and inflammatory chemicals damage underlying tissues

Infant Botulism - Disease at a Glance

1. Baby inhales or ingests C. botulinum endospores, particularly in honey 2. Endospores germinate in anaerobic environment of intestinal tract. Vegetative cells grow, reproduce, and release botulism toxin. 3. Toxin is absorbed into blood and circulates throughout the body 4. Botulism produces constipation and weak cry 5. Gradually the toxin paralyzes muscles, including neck muscles and the diaphragm Cause: Clostridium botulinum (anaerobic, endospore-forming, Gram-positive rod) Virulence Factors: - Endospores survive improper canning and resist antimicrobial drugs, seven antigenitcally distinct forms of botulism toxin Portal of Entry - inhalation of endospores or ingestion of contaminated food Signs and Symptoms: - Constipation is the first symptom. Muscle weakness, described as "floppy baby syndrom", causes weak cry, poor feeding (weak suckling), loss of head control, and respiratory distress. Infant may experience lethargy and descending paralysis. Incubation Period UNKNOWN Susceptibility: - infants, esp those under 6 months old Treatment: - supportive therapy, including keeping the airway clear and monitoring respiratory functions. Botulism immune globulin (BIG) reduces the length of the disease Prevention: - don't feed honey to babies less than a year old

ELISA steps

1. Each of the wells in the plate is coated with antigen molecules in solution. 2. Excess antigen molecules are washed off, and another protein (such as gelatin) is added to the wells to completely coat any of the surface not coated with antigen. 3. One well is assigned to each serum being tested, and a sample of the serum is added to that well. Whenever a serum sample contains antibodies against the antigen, the antibodies bind to the antigen affixed to the plate. 4. Anti-antibodies labeled with an enzyme are added to each well. 5. The enzyme's substrate is added to each well. The enzyme and substrate are chosen because their reaction results in products that cause a visible color change.

Bacteria cause disease in two ways:

1. Infect cells of the nervous system - Ex. Meningitis & Leprosy 2. Bacteria growing elsewhere release toxins that affect neurons - Ex. Botulism & Tetanus

Pathogenesis of Dengue Fever

1. Infected mosquito bites human 2. Dengue virus infects monocyte 3. Dengue fever 4. Recovery, resulting in antibodies against dengue virus in blood

4 Steps of Pathogenesis for Spotted Fever Rickettsiosis

1. Infected tick introduces R. rickettsii in its saliva. This occurs only after the tick has fed for at least 6 hours. Active bacteria are released into the mammalian host's circulatory system. 2. R. rickettsii triggers endocytosis from cells lining blood vessels (endothelium); then it lyses the endosome's membrane, escaping into the cytosol 3. Rickettsias divide every 8-12 hours in the host cell's cytosol. Daughter rickettsias escape from long cytoplasmic extension of the host cell and infect other endothelial cells. 4. R. rickettsii secretes no tozins, and disease is NOT THE product of immune response. Apparently, damage to the endothelial cells leads to leakage of blood into the tissue which results in low blood pressure and insufficient nutrient and oxygen delivery to the body's organs

9 Steps of Chickenpox and Shingles

1. Inhalation of varicella-zoster virus 2. Infected cells replicate and release virus into the blood (viremia) and lymph 3. Viruses infect liver, spleen, and lymph nodes throughout the body 4. Second viremia spreads viruses to skin, causing extensive rash 5. Viruses shed through respiratory droplets and fluid from skin lesions 6. Immune systems eliminates viruses from blood and most cells 7. Some viruses become latent (dormant) in nerve ganglia 8. Upon reactivation, viruses travel inside nerve cells down the nerve to infect skin cells 9. Rash develops in the band of skin innervated by the infected nerve

Poxvirus Disease Progression (6 steps)

1. Macule (flat, reddened skin lesion) turns into 2. Papule (raised red sore/lesion progressed from macule) 3. Vesicle (previous lesion fills w/ clear fluid) 4. Pustule (vesicle progress to pus-filled lesions) 5. Crust (poxvirus pustules dry to form crusts) 6. Scar (because the lesions penetrate the dermis)

Primary Tuberculosis Pathogenesis

1. Mycobacterium typically infects the respiratory tract via inhalation of respiratory droplets from infected individuals. 2. Macrophages in alveoli phagocytize mycobacteria but are unable to digest them, in part because the bacterium inhibits fusion of lysosomes to endocytic vesicles 3. Instead, bacteria replicate freely within macrophages, gradually killing the phagocytes. Bacteria released from dead macrophages are phagocytized by other macrophages, beginning the cycle anew. 4. Infected macrophages present antigen to T cells which produce lymphokines that attract an activate more macrophages and trigger inflammation. Tightly packed macrophages surround the site of infection, forming a tubercle over a two- to three-month period. 5. Other cells deposit collagen fibers, enclosing infected macrophages and lung cells within the tubercle. Infected cells in the center die, releasing M. tuberculosis and producing caseous necrosis- the death of tissue that takes on a cheese-like consistency due to protein and fat released from dying cells. A stalemate between the bacterium and the body's defenses develops.

Development of Acne (4 steps)

1. Normal Skin - oily sebum produced by glands reaches the hair follicle and is discharged onto the skin surface via the pore 2. Whitehead - Inflamed skin swells over the pore when bacteria infect the hair follicle, causing the accumulation of colonizing bacteria and sebum 3. Blackhead - Dead and dying bacteria and sebum form a blockage of a pore 4. Pustule Formation - Sever inflammation of the hair follicle causes pustule formation and rupture, producing cystic acne, which is often resolved by scar tissue formation

The life cycle of Toxoplasma gondii

1. Sexual reproduction of parasite occurs in cat's digestive system, and immature oocysts are shed in cat feces 2. Oocyst produces internal sporozoites 3a. Rodent or bird injests sporulated oocysts, or 3b. livestock or human consumes them, becoming accidental hosts 4a (rodent). Sporozoites invade tissue, developing into bradyzoites within cells. Masses of bradyzoites become pesudocysts, or 4b (livestock). sporozoites invade tissue, developing into bradyzoites and forming pseudocysts 5a. (rodent) pseudocysts are ingested by cat in wild prey or undercooked meat 5b. (livestock) Pseudocysts are ingested by humans in undercooked meat

3 Clinical Stages of African Sleeping Sickness

1. Site of bite becomes lesion containing necrotic (dead) tissue and rapidly dividing parasites 2. Parasites in the blood create fever, lymph node swelling, headache, muscle and joint aches 3. After 1-2 years, meningoencephalitis results when protozoa invade the CNS, partial paralysis, confusion, daytime sleepiness with nighttime sleep disturbance

The life cycle of Plasmodium

1. Sporozoites are injected into host during blood meal 2. Sporozoites invade liver cells and undergo schizogony 3. Liver cell ruptures and releases numerous merozoites into blood 4. Erythrocytic Cycle - Trophozoites undergo schizogony to produce merozoites, which are released. - Free merozoites penetrate erythrocytes - A merozoite becomes a trophozoite - (this cycle repeats) 5. Some merozoites develop into gameocytes within erythrocytes 6. Mosquito ingests gameocytess during blood meal 7. Gametocytes become gametes that fuse to form zygote 8. Zygote differentiates into ookinete, which becomes an oocyst in gut wall 9. Oocysts forms sporozoites, ruptures, and sporozoites migrate to salivary glands of mosquito (cycle repeats)

Pathogenesis of dengue hemorrhagic fever (DHF)

1. Subsequent infection with a different strain of dengue virus 2. Virus-antibody complexes form 3. Virus-antibody complexes phagocytized by Antigen-Presenting Cells 4. Activation of Memory T cells 5. Increased production of inflammatory cytokines 6. Dengue hemorrhagic fever, severe illness, shock, hemorrhage, death (10-50%)

The life cycle of Schistosoma, a blood fluke.

1. The free-swimming larvae are infective and can penetrate human skin 2. Larvae lose their tails and develop into adults in blood vessels of the liver or bladder; the adults mate 3. Eggs are passed into the environment via feces or urine 4. In water, eggs hatch into free-swimming larvae 5. Larvae penetrate freshwater snails 6. Larvae reproduce asexually in snail, forming a different larval form 7. These different larvae escape the snail host and swim in the water

4 stages of American trypanosomiasis

1. The site of the bug's bite swells. 2. The generalized stage is characterized by fever, swollen lymph nodes, myocarditis (inflammation of the heart muscle), splenomegaly, and enlargement of the esophagus and colon. 3. The chronic stage is asymptomatic and can last for years. 4. A final symptomatic stage is characterized primarily by congestive heart failure following the formation of pseudocysts, which are clusters of parasites in heart muscle tissue.

The life cycle of Trypanosoma cruzi

1. Trypanosomes become infective in hindgut of kissing bug 2. Infective trypanosomes are deposited in feces of kissing bug at bite wound site 3. Scratching introduces trypanosomes into the blood 4. Trypanosomes travel in blood, penetrate cells, and transform into a nonflagellated form 5. Nonflagellated trypanosome multiplies bu binary fission inside cells 6. Nonflagellated trypanosomes transform, each developing a flagellum attached to the parasite's body with an undulating membrane; these flagellated forms burst out of infected cells into the blood. Flagellated trypanosomes do not multiply in the blood 7. Some flagellated cells infect other body cells, becoming nonflagellated in the process 8. Flagellated trypanosomes in the blood are ingested by kissing bug while it feeds 9. Flagellated parasites might develop in the midgut of the bug into a different flagellated form that multiplies by binary fission

Events Leading to Hemolysis

1. antibodies against a foreign ABO antigen combine with the antigen on transfused red blood cells (transfusion) 2. cells are agglutinated, and the complexes bind complement (agglutination and complement binding) 3. resulting hemolysis releases large amounts of hemoglobin into the blood stream

Steps for Processing Endogenous Antigens (6)

1. each polypeptide is cut into smaller 8-12 AA pieces by proteases 2. the pieces, including the epitopes, move into the endoplasmic reticulum and bind onto complementary antigen-binding grooves of MHC class I molecules that were previously inserted into the membrane of the ER 3. The ER membrane, now loaded with MHC class I proteins and epitopes, is packaged by a Golgi body to form vesicles 4. The vesicles fuse with the cytoplasmic membrane 5. The result is that the cell displays the MHC I protein-epitope complex on the cell's surface **Since every nucleated cell in the body makes MHC class I, each cell displays epitopes from every endogenous antigen and every autoantigen inside that cell. This allows immune cells to detect all the antigens inside cells

Pathogenesis of Shigellosis

1. pathogen attaches to epithelial cells in the large intestine 2. shigella triggers endocytosis 3. shigella multiplies in cytosol 4. shigella invades neighboring epithelial cells, thus avoiding immune defenses --> polymerizes the host's actin fibers, propelling itself out of the host cell and into adjacent cells 5. an abscess forms as epithelial cells are killed by the infection 6. shigella that enters the blood is quickly phagocytized and destroyed. No bacteremia.

steps of antibody sandwich ELISA

1. the plates are first coated with antibody rather than antigen. 2. the sera from individuals being tested are added to the wells, and any virus in the sera will bind to the antibody attached to the well 3. Finally, each well is flooded with enzyme-labeled antibodies specific to the antigens of the virus.

Actions of Alpha and Beta Interferons (picture)

1. virus infects cell 2. viral components trigger activation of type I IFN genes 3. IFN alpha and bet are released and bind to receptors on the same and nearby cells 4. Binding activates genes for AVPs, though AVPs remain inactive at this time (IN NEIGHBOR UNINFECTED CELLS) 5. Infected cell dies, releasing viruses 6. If a new cell is infected, viral components activate the AVPs (that were already in there by step 4) 7. Active AVPs degrade mRNA and bind to ribosomes, which stops protein synthesis, preventing viral replication

Review - Which fungal disease is found almost exclusively in the southwestern United States? A. Coccidioidomycosis. B. Blastomycosis. C. Histoplasmosis. D. Pneumocystis pneumonia.

A - Coccidioidomycosis is found in the southwestern United States and northern Mexico.

Review - Which of these types of virus is most likely to cause human cancer? A. A DNA virus. B. A lytic bacteriophage. C. A lysogenic bacteriophage. D. An RNA virus.

A - DNA viruses are most likely to cause cancer because their DNA can integrate into the human genome, activating proto-oncogenes or interfering with repressor genes (tumor suppressor genes). Among RNA viruses, retroviruses are most likely to cause cancer, since they convert their RNA genomes to DNA through reverse transcription.

Review - Which parasite is diagnosed by applying transparent sticky tape to the anus and perianal region followed by microscopy? A. Enterobius. B. Anisakis. C. Cysticerci. D. Cryptosporidium.

A - Female Enterobius vermicularis (commonly called pinworm) migrates to the anus at night to deposit her eggs perianally; such eggs can be observed on sticky tape that has been applied to the anus.

Review - What is a tubercle? A. A cluster of tightly packed macrophages surrounding Mycobacterium tuberculosis bacteria. B. A leftover alveolus after death due to Mycobacterium tuberculosis infection. C. A group of T lymphocytes surrounding Mycobacterium tuberculosis cells. D. A group of bacteria, of which the outer layer dies, providing protection to bacteria deeper inside the group.

A - Macrophages recruited to the site of infection by M. tuberculosis surround the bacteria; they develop into a tubercle over a two- to three-month period.

Review - Which form of plague can be transmitted from person to person? A. Pneumonic plague only. B. Bubonic plague only. C. None of these forms of plague is communicable. D. "Black Death" plague.

A - Pneumonic plague can be transmitted from one person to another through respiratory droplets.

Review - What is the best way to prevent measles? A. Immunization. B. Excellent hand hygiene. C. Avoiding contact with measles patients. D. Respiratory precautions.

A - The MMR vaccine is the best way to prevent measles

Review - Which people are at highest risk of contracting toxoplasmosis? A. People who eat infected meat. B. A male fetus. C. Pregnant women who own cats. D. Immunocompromised people.

A - Toxoplasmosis is most commonly transmitted by consumption of undercooked meat; therefore, carnivores are at highest risk.

Review - What is the most common cause of bacterial endocarditis? A. Viridans streptococci. B. Staphylococcus aureus. C. Streptococcus pneumoniae. D. Escherichia coli.

A - Viridans streptococci are members of a group of Gram-positive bacteria belonging to the genus Streptococcus that produce a green pigment when cultured on blood agar.

transfusion reaction develop as follows:

A. If the recipient has preexisting antibodies to foreign antigens, then the donated blood cells will be destroyed immediately --> either the antibody-bound cells will be phagocytized by macrophages and neutrophils, or the antibodies will agglutinate the cells and complement will rupture them (a process called hemolysis) B. In most people, production of antibodies against foreign ABO antigens is stimulated not by exposure to foreign blood cells but instead by exposure to antigenically similar molecules found on a wide range of plants and bacteria --> Individuals encounter and make antibodies against these antigens on a daily basis, but only upon receipt of a mismatched blood transfusion do the antigens cause problems C. If the recipient has no preexisting antibodies to the foreign blood group antigens, then the transfused cells circulate and function normally, but only for a while—that is, until the recipient's immune system mounts a primary response against the foreign antigens and produces enough antibody to destroy the foreign cells --> This happens gradually over a long enough time that the severe symptoms and signs mentioned above do not occur

Cytotoxic Drugs - Immunosuppressive Drugs (4)

Action: Block cell division nonspecifically - inhibit mitosis and cytokinesis (cell division) - Given that lymphocyte proliferation is a key feature of specific immunity, blocking cellular reproduction is a powerful, although very nonspecific, method of immunosuppression - Ex. Cyclophosphamide, Azathioprine, mycophenolate mofetil, brequinar sodium, and leflunomide

lymphocyte-depleting therapies - Immunosuppressive Drugs (7)

Action: Kill T cells nonspecifically, or kill activated T cells, or inhibit IL-2 reception - an attempt to reduce the many adverse side effects associated with the use of less specific immunosuppressive drugs - Because they target a narrow range of cells, they produce fewer undesirable side effects than less specific drugs - effective in reversing graft rejection - Ex. antiserum called antilymphocyte globulin, which is specific for lymphocytes - Ex. Another, more specific, antilymphocyte technique uses monoclonal antibodies against CD3, which is found only on T cells - Ex. even more specific monoclonal antibody is directed against the interleukin 2 receptor (IL-2R), which is expressed mainly on activated T cells

Active or Passive Acquired Immunity

Active - either the immune system responds actively to antigens via antibody or cell-mediated responses Passive - or the body passively receives antibodies from another individual

What can happen as a result of many mast cells degranulating at once, releasing large amounts of histamine and inflammatory mediators? Is this response considered local or systemic?

Acute anaphylaxis AKA "anaphylactic shock" - systemic!

Which of the following statements is true? - Memory B cells are typically established when the B cell binds to an antigen. - Adaptive defenses include both humoral and cellular immunity. - Adaptive defenses include humoral immunity only. - Innate defenses are enough to keep a person healthly

Adaptive defenses include both humoral and cellular immunity - This answer is correct. Adaptive defenses are operating optimally when both humoral and cellular immunity are working together in response to a pathogen.

Comparison of the Polio Vaccines - Salk Vaccine Inactivated polio vaccine (IPV)

Advantages: Effective; inexpensive; stable during transport and storage; poses no risk of vaccine-related disease Disadvantages: Requires booster to achieve lifelong immunity; must be injected; requires higher community immunization rate than does OPV

What is meant by the clonal expansion of a B cell? - An activated B cell will immediately begin to produce antibodies. - An activated B cell will engulf and digest anything foreign. - An activated B cell will kill infected host cells. - An activated B cell divides into cells that give rise to memory B cells and plasma cells.

An activated B cell divides into cells that give rise to memory B cells and plasma cells. - This answer is correct. The activated B cell divides until there are many clones. Some differentiate into memory cells, other become plasma cells that produce and secrete antibodies.

What is the primary benefit of vaccination? - An immune response will occur quicker upon future exposure to the pathogen. - Vaccinated persons get used to the symptoms of a disease. - Vaccines provide antibodies against the pathogen that persist forever in the body. - Unvaccinated persons can never mount an immune response to a pathogen.

An immune response will occur quicker upon future exposure to the pathogen

* MHC I and II are nonspecific. What determines their binding diversity? (5)

An individual's genes! - Some epitopes won't be bound to the MHC of a particular person --> such epitopes typically don't trigger an immune response - MHC molecules determine which epitopes might trigger immune responses - explains why some people are allergic to peanuts and others are not

Synthesis of RNA and polypeptides of HIV

An infected cell transcribes integrated HIV genes to produce messengerr RNA and multiple copies of viral ssRNA that will act as genomes for new viruses. Ribosomes within the infected cell translate mRNA to make viral-encoded polypeptides. These include attachment proteins, integrase, and a large polypeptide composed of inactive reverse transcriptase and capsomeres. The attachment proteins are inserted in the host's cytoplasmic membrane.​

Review - Which type of vaccine most closely mimics a real infection with a pathogen? A. Subunit vaccines B. Attenuated vaccine C. Whole agent vaccines D. Toxoid vaccines

Attenuated (modified live) vaccine consists of weakened pathogens that can infect the host without causing (severe) disease. They most closely mimic a real infection

Review - Under which conditions can dengue hemorrhagic fever occur? A. A person develops an exceptionally strong immune response to an initial dengue virus infection. B. A person who previously had dengue fever is infected with a different serotype of dengue virus. C. An infected patient has a poor adaptive immune response. D. A person is infected with dengue virus 1.

B

Review - What are the major signs and symptoms of the last stage of Lyme disease? A. Death. B. Severe arthritis. C. The expanding rash at the bite site. D. Neurological symptoms and cardiac dysfunction.

B

Review - What is a major drawback of treatments of Cytomegalovirus (CMV) infection? A. The treatments have serious side effects. B. The treatments limit spread of the disease but do not cure it. C. The treatments are very expensive. D. The treatments cure the disease, but they do not limit the transmission of the virus.

B

Review - What is a mechanism by which human herpesvirus 4 (HHV-4, Epstein-Barr virus) causes cancer? A. HHV-4 encourages rapid replication of infected cells. B. HHV-4 suppresses apoptosis in infected cells. C. HHV-4 causes cells to migrate throughout the body. D. HHV-4 causes mutations in an infected cell's genome.

B

Review - What is dysentery? A. Severe diarrhea with vomiting. B. A severe diarrhea with blood and mucus. C. Severe diarrhea with rash. D. Severe diarrhea with fever.

B

Review - Which is the most common type of pneumonia? A. Staphylococcal pneumonia. B. Pneumococcal pneumonia. C. Mycoplasmal pneumonia. D. Ventilator-associated pneumonia.

B

Review - Which of these factors complicates the elimination of yellow fever in the tropics? A. It is not possible to eradicate mosquitoes. B. Jungle monkeys are a natural reservoir for yellow fever virus. C. It is hard to eliminate the breeding locations of mosquitoes. D. There is no effective vaccine available.

B

What is the most effective way to prevent African sleeping sickness? A. Immunization. B. Widespread tsetse fly control. C. Spraying the skin with antibiotics. D. Prophylactic drugs.

B

Review - What is the major difference between the epidermis and the dermis of the skin? A. The epidermis receives more blood than the dermis. B. Cells of the dermis are alive, whereas the epidermis consists of dead, keratinized cells. C. The epidermis secretes more sebum than the dermis. D. The epidermis is more hospitable to microbes than the dermis.

B - Cells of the dermis divide continuously; new cells push the epidermal layers toward the surface, replacing the outer layer, which is shed.

Review - If a person has had gonorrhea, what is the best way to prevent the disease from recurring? A. Oral contraceptives. B. Abstinence, monogamy, or use of condoms. C. Prophylactic (preventive) drugs. D. Immunization.

B - Contracting gonorrhea does not confer long-term specific immunity, so patients can be reinfected; abstinence, monogamy, or use of condoms reduce the likelihood of reinfection.

Review - How do enveloped viruses enter human cells? A. By direct penetration. B. By fusion of the viral envelop with the cell membrane. C. They do not enter cells; instead, they remain outside and only inject their nucleic acid into the cell. D. Budding

B - Enveloped viruses fuse their envelope with the cell membrane after attaching to cell receptors. Glycoproteins on the surface of enveloped viruses bind to receptors on the surface of a host cell. The viral envelop fuses with the host cell membrane, so that the virus enters the cell in a membrane vesicle. After synthesis of viral genomes and proteins, viruses leave the cell by budding slowly from the cell without killing it. The results in persistent infections.

Review - What is the best way to prevent cervical cancer? A. Safe sex. B. Immunization. C. Oral contraceptives. D. Proper genital hygiene.

B - Immunization is the best way to prevent cervical cancer, which is caused by human papillomaviruses

Review - Where are Koplik's spots located? A. On the face. B. Inside the mouth. C. On the chest. D. On the back.

B - Koplik's spots are found on the mucous membranes inside the mouth.

Review - How are the manifestations of inhalational anthrax different from those of influenza? A. Inhalational anthrax does not cause a fever, whereas influenza does. B. Chest discomfort is a symptom of anthrax, but not influenza. C. Rhinorrhea is a sign of inhalational anthrax, but not influenza. D. Inhalational anthrax causes coughing, whereas influenza does not.

B - One symptom that is common in inhalational anthrax but not in influenza is chest discomfort.

Review - What is the term used for microbiota that normally do not cause disease but that might cause disease when the balance of microbiota is disrupted by use of antimicrobial drugs? A. Transient pathogens. B. Opportunistic pathogens. C. True pathogens. D. Commensal pathogens.

B - Opportunistic pathogens do not normally cause disease but can do so when the balance of microbiota is disrupted. Opportunistic pathogens do not normally cause disease but can do so when a patient is immune compromised or when the balance of normal microbiota is disrupted. The microbes may be commensal, mutualistic, or transient; however, if they cause disease, they are referred to as opportunistic pathogens.

Review - Why are blood cells infected by the intracellular parasite Plasmodium not destroyed by cytotoxic T cells? A. Plasmodium neutralizes the chemicals that cytotoxic T cells inject into infected cells. B. Infected cells do not present antigens on major histocompatibility complexes on their surface. C. Plasmodium changes the major histocompatibility proteins of the cells they infect, so that cytotoxic T cells cannot recognize them. D. Plasmodium infects and kills cytotoxic T cells.

B - Plasmodium infects red blood cells, which do not present antigens on major histocompatibility complexes on their surface. Without the presence of surface antigens, cytotoxic T cells do not recognize infected cells.

Review - Why is the liver considered part of the digestive system? A. It produces hydrochloric acid, which limits microbial growth in the stomach. B. It produces bile, which helps digest fats. C. Food passes through the liver, which helps grind up the food. D. It produces gastric juices, which help digest food in the stomach.

B - The liver produces bile, which is excreted into the duodenum, where it breaks up fats

Review - How is Lyme disease transmitted? A. From contact with contaminated deer. B. By direct contact. C. Via tick bites. D. Via inhalation.

C

Which of the following statements about lymphocytes is FALSE? - Lymphocytes have different types of CD molecules in their cytoplasmic membranes. - Once they are mature, they migrate to secondary lymphoid organs. - B and T lymphocytes can be differentiated using a bright-field light microscope. - Lymphocytes have integral surface proteins by which they can be recognized. - The glycoproteins on the surface of a lymphocyte are designated with the prefix CD, for "cluster of differentiation."

B and T lymphocytes can be differentiated using a bright-field light microscope - FALSE STATEMENT

Review - Which lymphocyte controls Humoral immune response?

B cells

Review - Why are infections caused by Pseudomonas aeruginosa rare? A. Because the bacterium does not have a lot of virulence factors. B. Because the bacterium cannot readily bypass intact skin. C. The bacterium cannot withstand soap, so general hygiene is a good preventive measure. D. The bacterium is rarely present in the environment.

Because the bacterium cannot readily bypass intact skin.

What is the function of the CD8 receptor? - Bind to MHC molecules - Activate cytokines - Produce gamma interferon - Produce IL-2

Bind to MHC molecules

Review - How does Shiga toxin damage cells? A. It helps Shigella bacteria attach to host intestinal cells. B. It causes leakage of cell membranes so that cells die. C. It stops protein synthesis in cells, killing them. D. It damages mitochondria so that cells do not produce enough energy and subsequently die.

C

Review - What is the epiglottis? A. An air-filled, hollow cavity in the bones of the skull. B. A flap descending from the roof of the mouth. C. The structure that closes off the larynx while swallowing. D. Lymphoid tissue near the junction of the nasal cavity and the pharynx.

C

Review - What is the natural reservoir of Legionella pneumophila? A. Humans. B. Air conditioning ducts. C. Freshwater amoebas. D. Aquatic bacteria.

C

Review - Which organism causes the form of gastroenteritis known as traveler's diarrhea? A. Salmonella enterica. B. Shigella dysenteriae. C. Escherichia coli. D. Clostridium difficile.

C

Review - Why is infection with human herpesvirus 4 (HHV-4, Epstein-Barr virus) usually asymptomatic in young children? A. The virus does not replicate well in young children. B. Young children do not have many lymphocytes than can be infected by the virus. C. The immature immune system of young children does not produce severe tissue damage. D. The strong immune response of young children effectively stops the infection before signs and symptoms occur.

C

Review - What do the five bacterial species responsible for 90% of all cases of meningitis have in common? A. They all have capsules. B. They are all intracellular pathogens. C. They all resist phagocytosis. D. They are all Gram-negative bacilli.

C - All the bacteria responsible for most cases of meningitis have virulence factors that allow them to resist phagocytosis.

Review - Who is at greatest risk of contracting tularemia? A. People who drink unpasteurized milk. B. Pregnant women. C. Animal handlers and rabbit hunters. D. Young children.

C - Animal handlers and rabbit hunters are often in contact with the most common reservoirs of the pathogen, so they are at highest risk

Review - What is the main difference between superficial and cutaneous mycoses? A. Superficial mycoses do not involve secreted toxins, whereas cutaneous mycoses do. B. Superficial fungi are diagnosed using potassium hydroxide preparations of skin or nail scrapings, whereas cutaneous mycoses are more easily diagnosed by observing fluorescence under ultraviolet radiation. C. Superficial mycoses do not trigger immune responses, whereas cutaneous mycoses do. D. Superficial mycoses are caused by soil fungi, whereas cutaneous mycoses are caused by normal fungal microbiota.

C - Because superficial fungi do not penetrate tissues, they do not trigger the body's immune responses.

Review - Which of these virulence factors allows Staphylococcus aureus to hide from phagocytes? A. Hyaluronidase. B. Beta-lactamase C. Coagulase. D. Lipase.

C - Coagulase clots blood, which hides S. aureus from phagocytes.

Review - Which pathogen of the digestive system uses a ventral adhesive disk to attach to the intestinal wall, scarring the wall? A. Enterobius vermicularis. B. Taenia solium. C. Giardia intestinalis. D. Cryptosporidium parvum.

C - Giardia intestinalis attaches to the intestinal wall with a ventral adhesive disk, causing scarring of the intestinal wall

Review - Which hepatitis virus causes most hepatitis deaths in the United States? A. Hepatitis A virus. B. Hepatitis B virus. C. Hepatitis C virus. D. Hepatitis E virus.

C - Hepatitis C virus kills 10,000 to 20,000 Americans each year.

Review - At what stage of the disease are syphilis patients most contagious? A. The latent phase. B. The secondary phase. C. The primary phase. D. The tertiary phase.

C - In the early stages of the disease, the spirochetes are more numerous, so patients are most contagious.

Review - How is legionellosis different from most other forms of pneumonia? A. It is rarely fatal, compared to other forms of pneumonia. B. It is preventable by immunization. C. It is not communicable. D. It infects only healthy people rather than those whose immune system is compromised.

C - Legionellosis is contracted from inhaling contaminated water; it is acquired by airborne transmission

Review - How can bacteriophages increase the ability of bacteria to cause disease in humans? A. By enhancing bacterial growth. B. Through destruction of the host genome. C. Through lysogenic conversion. D. By becoming a provirus.

C - Lysogenic conversion refers to the ability of some lysogenic phages to change the phenotype of bacteria. Lysogenic phages can insert their genome into the genome of their bacterial hosts, resulting in lysogenic conversion. They can introduce toxin-encoding genes or other virulence factors into the bacterial genome, increasing the ability of the bacteria to cause disease.

Review - The environment inside the human intestinal tract lacks oxygen. Name all of the following groups of microbes can grow in the intestines. A. Obligate anaerobes and aerotolerant anaerobes. B. Obligate anaerobes and facultative anaerobes. C. Obligate anaerobes, facultative anaerobes, and aerotolerant anaerobes. D. Microaerophiles, obligate anaerobes, and facultative anaerobes.

C - Obligate anaerobes, facultative anaerobes, and aerotolerant anaerobes can all grow in the absence of oxygen. Obligate aerobes and microaerophiles require the presence of oxygen, whereas obligate anaerobes, facultative anaerobes, and aerotolerant anaerobes can all grow in the absence of oxygen.

Review - How do herpesviruses enter a host cell? A. By direct injection of the capsid and its contents. B. The virus does not enter; it injects only its DNA into a host cell. C. By fusion of their viral envelope with the host cytoplasmic membrane. D. Through endocytosis.

C - The envelope of human herpesvirus fuses with the cytoplasmic membrane to introduce the capsid into the host cell.

Review - Which is the active, feeding stage of a protozoan? A. An apicomplexan. B. A cyst. C. A trophozoite. D. A mitosome.

C - The feeding stage of a protozoan is a trophozoite. The trophozoite is the active, feeding stage of protozoa that can cause disease.

Review - Which sexually transmitted pathogen is a protozoan? A. Candida albicans. B. Neisseria gonorrhoeae. C. Trichomonas vaginalis. D. Treponema pallidum.

C - Trichomonas vaginalis is a parabasalid protozoan.

Disease at a Glance - Pertussis (Whooping Cough)

Cause -- Bordetella pertussis (Gram-negative coccobacillus). Virulence factors -- Adhesins that attach to tracheal cells; survives within phagosome; pertussis toxin causes human cells to make more receptors for Bordetella. Portal of entry -- Inhalation. Signs and symptoms -- Catarrhal stage begins with signs and symptoms resembling the common cold that last one to two weeks. The following paroxysmal stage lasts two to four weeks and is characterized by persistent, violent coughing spells that consist of three or four coughs without a breath, followed by a high-pitched, wheezing inhalation, or "whoop." The convalescent stage lasts several weeks as the cough subsides. Incubation period -- 6-20 days, with an average of 7-10 days. Susceptibility -- Unimmunized children. Treatment -- Supportive care; erythromycin has only little effect on the course of disease but helps eliminate B. pertussis in the respiratory tract and thus helps reduce spread of pertussis to others. Prevention -- DTaP vaccine.

Disease at a Glance - Lyme Disease

Cause -- Borrelia burgdorferi (Gram-negative spirochete). Virulence factors -- Uses manganese in place of iron; changes outer membrane antigens frequently; endotoxin. Portal of entry -- Skin via bite of infected tick. Signs and symptoms -- "Bull's-eye" rash, malaise, headache, dizziness, stiff neck, severe fatigue, fever, chills, muscle and joint pain, and lymphadenopathy. Incubation period -- 7 to 14 days. Susceptibility -- People in highly endemic areas are particularly susceptible because of increased exposure. Treatment -- Doxycycline or amoxicillin antibiotic treatment for three to four weeks if the disease is caught early. Later disease may require intravenous treatment, depending on severity. Prevention -- Wear light-colored, tight-fitting clothes outdoors to limit tick exposure, use tick repellent, promptly remove ticks, examine skin for ticks and bites, and avoid tick-infested areas. The Lyme disease vaccine for humans is no longer commercially available.

Disease at a Glance - Pelvic Inflammatory Disease (PID)

Cause -- Chlamydia trachomatis (Gram-negative obligate intracellular bacterium); Neisseria gonorrhoeae (Gram-negative diplococcus bacterium); or Gardnerella vaginalis (Gram-positive coccobacillus bacterium) in rare instances. In 30-40% of cases, PID is caused by infection with multiple bacteria simultaneously. Virulence factors -- Chlamydia—small size, intracellular lifestyle; Neisseria—capsule, fimbriae, lipid A; Gardnerella—ability to inhibit movement of neutrophils, adhesins, formation of biofilm. Portal of entry -- Mucous membrane of vagina, sexual transmission, and then migration ascending into the uterus or uterine tubes. Signs and symptoms -- Inflammation, fever, abdominal pain. Left untreated, PID can lead to ectopic pregnancies and sterility. Incubation period -- Months to years after initial infection. Susceptibility -- Women with untreated gonorrhea or chlamydial infections, especially those under age 20. Treatment -- Antimicrobial drugs such as ofloxacin, metronidazole, doxycycline, and/or ceftriaxone. Prevention -- Abstinence or mutual monogamy with an uninfected partner; early treatment of all STDs. Condoms provide some protection from Neisseria infection.

Gas Gangrene - Disease at Glance

Cause -- Clostridium species, particularly C. perfringens (anaerobic, Gram-positive, endospore-forming rod). Virulence factors -- Endospore, 11 toxins, rapid growth, and cell division. Portal of entry -- Clostridium endospores are introduced into dead tissue via a traumatic event such as surgical incision, puncture, gunshot wound, crushing trauma, abortion, or broken bones punching through the skin. Signs and symptoms -- Increased pain and swelling around injury, fever, initially pale skin that turns dusky and then progresses to dark red or purple, foul-smelling drainage from tissues, crepitation (crackly sound due to gas under the skin), and tachycardia. Untreated gas gangrene causes shock, coma, and death, often within a week of infection. Incubation period -- Generally less than 24 hours and no more than three days. Susceptibility -- Individuals with deep, lacerating wounds, particularly "dirty" wounds. Treatment -- Gas gangrene is a medical emergency, and prompt identification and treatment are crucial. Dead tissue must be surgically removed, and antitoxin, penicillin, and clindamycin administered. -- Oxygen applied under high pressure may also be effective Prevention -- Difficult to prevent because the organism is common in soil -- Proper cleaning of wounds.

Review - Consider antigenic drift and antigenic shift. Which is the reason that a new influenza vaccine is necessary every year? A. Both antigenic drift and antigenic shift. B. Neither antigenic drift nor antigenic shift. C. Antigenic shift only. D. Antigenic drift only.

D

Disease at a Glance - Cryptococcal Meningitis

Cause -- Cryptococcus neoformans (spherical, single-celled basidiomycete yeast). Virulence factors -- Polysaccharide capsule resists phagocytosis; produces melanin, which inhibits intracellular digestion of the yeast. Portal of entry -- Inhalation of spores and/or dried yeast cells. Signs and symptoms -- Prolonged cough (lasting weeks or months), chest pain, fever, shortness of breath, night sweats, weight loss; proceeds to headache and meningitis. Incubation period -- Unknown, but probably two to nine months. Susceptibility -- Immunocompromised persons, especially HIV-positive individuals and AIDS patients; people exposed to bird droppings. Treatment -- Amphotericin B and 5-fluorocytosine coadministered for 6 to 10 weeks. Prevention -- It is difficult to avoid infection by this prevalent fungus; therefore, you should protect your immune system with healthy lifestyle choices.

Disease at a Glance - Toxic Shock Syndrome

Cause -- Exotoxin-producing strains of Staphylococcus aureus (Gram-positive coccus). Virulence factors -- Exotoxins, enterotoxins. Portal of entry -- Staphylococcus either grows in the vagina or enters the body through a wound, grows, and produces toxin that enters the bloodstream. Signs and symptoms -- Sudden onset of high fever, vomiting, rash, extremely low blood pressure, and sore throat. Incubation period -- Two to three days. Susceptibility -- Menstruating women who use highly absorbent tampons for extended periods, newly delivered mothers, and surgery patients are at higher risk. Treatment -- Supportive therapy is extremely important; administration of vancomycin and antistaphylococcal immunoglobulin. Prevention -- Avoid vaginal insertions such as highly absorbent tampons, vaginal sponges, or diaphragms, or use them intermittently and for shorter periods.

Disease at a Glance - Yellow Fever

Cause -- Flavivirus yellow fever virus (enveloped, positive, single-stranded RNA arbovirus with an icosahedral capsid). Virulence factors -- Intracellular replication cycle; adhesins. Portal of entry -- Injected by the mosquito Aedes aegypti; travels in blood to liver. Signs and symptoms -- Slight fever, muscle ache, headache, nausea, and vomiting for three to four days; about 20% of patients subsequently develop delirium, seizures, hemorrhaging, nosebleed, shock, and pronounced jaundice and severe fever, which give the disease its name. Incubation period -- Three to six days. Susceptibility -- Travelers to endemic regions of South America and Africa. Treatment -- No specific treatment; supportive nursing care. Prevention -- Avoid travel to endemic areas, or obtain immunization with live attenuated virus, effective for 10 years or more, and avoid mosquito bites by wearing protective clothing, using an insect repellent, and using mosquito netting.

Disease at a Glance - Tularemia

Cause -- Francisella tularensis (aerobic, Gram-negative coccobacillus). Virulence factors -- Intracellular pathogen of many mammals, birds, fish, arachnids, and insects; capsule discourages phagocytosis; inhibits lysosome fusion with phagosome; endotoxin. Portal of entry -- Via the bite of an infected tick, consumption of contaminated meat or water, inhalation, or direct contact with an infected animal. Signs and symptoms -- Sudden fever, chills, headaches, diarrhea, muscle and joint pain, and progressive weakness and fatigue. Inhalation cases may also exhibit chest pain, bloody sputum, and difficulty breathing. Skin ulcers may develop near the site of an infected tick bite. Tender, swollen lymph nodes appear near the site of infection within five days of infection. Incubation period -- Generally three to five days but can be up to two weeks. Susceptibility -- Animal handlers and rabbit hunters are at greatest risk, especially in the endemic areas of the southeastern United States. Treatment -- Intramuscularly administered streptomycin and tetracycline. Prevention -- Use insect repellent, and check for ticks. Wash hands after handling animal carcasses. Cook game thoroughly, and ensure water is from a safe source or sterilized.

Disease at a Glance - Hantavirus Pulmonary Syndrome (HPS)

Cause -- Hantavirus (enveloped, segmented, negative, single-stranded RNA (-ssRNA)(-ssRNA) virus). Virulence factors -- Intracellular replication helps avoid immune surveillance, proteins inhibit interferon responses. Portal of entry -- Inhalation of infected rodent excrement or saliva. Signs and symptoms -- Sudden onset of fever, fatigue, muscle aches, headache, chills, abdominal pain; followed by coughing and severe difficulty in breathing. Incubation period -- 14-30 days. Susceptibility -- People exposed to rodents in endemic areas. Treatment -- Supportive therapy for symptoms must occur under hospital supervision. Prevention -- Avoid rodent droppings, camp on ground sheet, carefully clean out potential rodent nesting sites at home, and keep home clean.

Disease at a Glance - Peptic Ulcer Disease

Cause -- Helicobacter pylori (Gram-negative, slightly helical motile bacterium). Virulence factors -- Flagella, adhesins, enzymes that inhibit phagocytosis, protein that blocks stomach acid production, urease. Portal of entry -- Probably through the mouth from fecal contamination of food or drink. Signs and symptoms -- Abdominal pain 30 minutes to several hours after eating or skipping a meal, pain that is relieved with antacids or milk, heartburn, indigestion, nausea, vomiting of blood, weight loss, fatigue, and dark or bloody stools. Incubation period -- Variable. Susceptibility -- Anyone who becomes colonized with H. pylori, particularly people with a family history of ulcers, who use tobacco, aspirin, ibuprofen, or other nonsteroidal anti-inflammatory medications, or who consume excessive alcohol. Treatment -- Amoxicillin and clarithromycin given in conjunction with acid-blocking drugs for one to two weeks. Prevention -- Good personal hygiene, adequate sanitation and proper food handling to decrease fecal-oral transmission, and lifestyle changes to reduce risk, including dietary changes to reduce stomach acid imbalances and reducing consumption of alcohol, tobacco, and aspirin-like pain medication.

Disease at a Glance - Herpes

Cause: -- Human herpesvirus 1 and human herpesvirus 2 (enveloped double-stranded DNA viruses). Virulence factors: -- Glycoproteins that allow viral attachment and entry, intracellular infections, proteins that inactivate complement and IgG. Portal of entry: -- Usually mucous membranes of the mouth or genitals. Signs and symptoms: -- A prodromal period of malaise, fever, and/or muscle pain may precede the typical blisters of a herpes infection. The blisters break, leaving a tender ulcer that may take several weeks to heal. Incubation period: -- 10 to 14 days. Susceptibility: -- Sexually active people have a greater risk of exposure to the disease, as does a baby during delivery by an infected mother. Treatment: -- Topical or oral administration of antivirals such as valacylovir, acyclovir, or peniciclovir can shorten outbreaks, but there is currently no cure. Prevention: -- Sexual abstinence, mutual monogamy, use of condoms, use of latex gloves by health care workers, and cesarean sections in infected mothers.

Disease at a Glance - Viral Hepatitis

Cause -- Hepatitis A virus (naked, positive, single-stranded RNA virus); hepatitis B virus (enveloped, partly double-stranded DNA virus); hepatitis C virus (enveloped, positive, single-stranded RNA virus); hepatitis delta virus (delta agent) (incomplete negative, single-stranded RNA virus); hepatitis E virus (naked, positive, single-stranded RNA virus). Virulence factors -- Intracellular replication cycle, adhesins. Portal of entry -- A and E—ingestion via fecal-oral route; B, C, delta—parenteral (blood- and fluid-borne) transmission. Signs and symptoms -- Jaundice, fatigue, abdominal pain, loss of appetite, nausea, and diarrhea. Additional symptoms: A—fever; B—vomiting and joint pain; C—dark urine; delta—vomiting and dark urine, E—vomiting and dark urine. Incubation period -- A—15 to 45 days; B—70 to 100 days; C—42 to 49 days; delta—7 to 24 days; E—15 to 60 days. Susceptibility -- Adults generally display more symptoms than children do and are at greater risk because of behavioral activities, though children are more at risk for chronic infections and complications thereof. Treatment -- For all—supportive therapy and rest; also: A—anti-HAV immunoglobulin; B—alpha interferon, adefovir dipivoxil, and lamivudine; C—sofosbuvir, ribavirin, and ledipasvir; delta— control of HBV coinfection. Prevention -- Practice good hygiene and drink sterilized water, especially when traveling in areas endemic for hepatitis A and E. Limit activities where body fluids may be acquired (such as sexual intercourse, sharing needles) to help prevent transmission of hepatitis B, C, and delta. Vaccines against hepatitis A virus and hepatitis B virus are available.

Disease at a Glance - Gonorrhea

Cause -- Neisseria gonorrhoeae (Gram-negative diplococcus). Virulence factors -- Capsule, fimbriae, lipooligosaccharide (lipid A, sugar), highly variable surface antigens among strains. Portal of entry -- Mucous membranes of genitalia; sexual transmission. Signs and symptoms -- Men generally experience painful urination and pus-filled discharge. Women are generally asymptomatic. Incubation period -- Two to five days. Treatment -- Simultaneous ceftriaxone and azithromycin. Prevention -- Effective: Sexual abstinence, mutual monogamy. Somewhat effective: Proper, consistent use of condoms.

Disease at a Glance - Schistosomiasis

Cause -- Parasitic helminth: Schistosoma mansoni (Caribbean, South America, and Africa), S. haematobium (Africa and India), and S. japonicum (Asia). Virulence factors -- Can burrow through human skin. Portal of entry -- Larvae burrow through skin. Signs and symptoms -- Swimmer's itch may occur at site of infection. There are no signs or symptoms as larvae travel the vascular system, but once the worms mature and mate, fever, chills, cough, and muscle aches occur. As trapped eggs die and calcify, renal failure, splenomegaly, increased blood pressure, bladder obstruction, distended abdomen, and heart failure may occur. Incubation period -- A few days for transient dermatitis; one to two months for acute symptoms. Susceptibility -- Individuals coming into contact with freshwater (lakes, rivers, or canals) in endemic areas are at risk. Treatment -- Praziquantel. Prevention -- In endemic areas, avoid swimming and wading in freshwater, boil water for one minute before drinking, and heat bath water to 150°F for five minutes before bathing.

Disease at a Glance - Polio

Cause -- Poliovirus [Enterovirus: naked, positive, single-stranded RNA (1ssRNA) virus]. Virulence factors -- Attaches to human intestinal cells; intracellular replication cycle; is relatively stable outside body. Portal of entry -- Ingestion in contaminated water. Signs and symptoms -- Five possibilities: asymptomatic; minor polio with temporary flulike signs and symptoms; nonparalytic polio with muscle spasms and neck pain; paralytic polio that infects the brain or spinal cord, resulting in paralysis of skeletal muscles; and postpolio syndrome, which is a crippling degeneration that occurs 30-40 years after infection. Incubation period -- 6 to 20 days. Susceptibility --Children are most at risk for acute, severe polio. Treatment -- Physical therapy for rehabilitation of weakened muscles; noninvasive ventilation to assist the patient's breathing. Prevention -- Inactivated (Salk) vaccine or attenuated oral (Sabin) vaccine.

Disease at a Glance - Variant Creutzfeldt-Jakob Disease (vCJD)

Cause -- PrP prion (infectious protein). Virulence factors -- Ability of abnormal, disease prion protein to convert normal prion protein into abnormal form; survives cooking and normal autoclaving. Portal of entry -- Ingestion of infected meat; transplant or transfusion of infected tissues. Signs and symptoms -- Irrational behavior; loss of muscle control; increasing inability to walk, talk, or maintain posture; muscle spasms; and a continuous writhing of the extremities. Death is inevitable. Incubation period -- Unknown, but most likely decades. Susceptibility -- At greatest risk are individuals who consumed beef in the United Kingdom between 1980 and 1996. Treatment -- None. Prevention -- Do not eat meat contaminated with infected nervous tissue. Destruction of potentially infected herds is necessary to prevent the spread of the infectious prion.

Disease at a Glance - Rabies

Cause -- Rabies virus (Lyssavirus, enveloped, negative, single-stranded RNA [2ssRNA] virus). Virulence factors -- Glycoprotein spikes on envelope serve as attachment proteins; triggers its own endocytosis by body cells; intracellular replication cycle. Portal of entry -- Via the bite or scratch of an infected animal. Signs and symptoms -- Pain or itching at site of infection, fever, headache, malaise, anorexia. Neurological manifestations include hydrophobia, seizures, disorientation, hallucinations, paralysis, and death. Incubation period -- Variable, generally one to two months, sometimes up to seven years. Dogs have been known to exhibit symptoms within 10 days of infection. Susceptibility -- Wild animals are particularly susceptible, but any unimmunized mammal may be infected. Animal handlers are at an increased risk of infection. Treatment -- Immediately wash the wound with soap and water, and begin postexposure prophylaxis (PEP) via administration of one dose of human rabies immunoglobulin (HRIG) and four doses of rabies vaccine (HDCV) over the course of one month. In cases where PEP was not administered and symptoms develop, treatment is supportive therapy. Prevention -- Immunization of dogs and cats. Animal handlers may also be immunized.

Disease at a Glance - Measles

Cause: -- Morbillivirus (rubeola virus) (enveloped, negative, single-stranded RNA virus). Virulence factors: -- Adhesion proteins, fusion proteins, intracellular infection. Portal of entry: -- Respiratory tract. Signs and symptoms: -- Fever, sore throat, headache, dry cough, conjunctivitis, Koplik's spots, and maculopapular rash. Incubation period: -- 8 to 12 days. Susceptibility: -- Unimmunized individuals. Treatment: -- Supportive therapy, ribavirin, vitamin A, and antibodies against the virus. Prevention: -- Immunization with the combined MMR (measles, mumps, and rubella) vaccine. The vaccine contains live, attenuated measles virus.

Disease at a Glance - Salmonellosis and Typhoid Fever

Cause -- Serotypes Typhi or Paratyphi of Salmonella enterica (Gram-negative, peritrichous bacillus) cause typhoid fever; serotypes Enteritidis and Typhimurium commonly cause salmonellosis. Virulence factors -- More than 2000 serotypes; ability to tolerate low pH; adhesins; type III secretion system; toxins that disrupt mitochondria, inhibit phagocytosis, rearrange cytoskeletons of eukaryotic cells, or induce apoptosis. Portal of entry -- Mouth and mucous membranes of the intestine by fecal-oral transmission; this involves ingestion of food or water contaminated with sewage from a carrier or ingestion of food directly handled by an asymptomatic carrier. Signs and symptoms -- Gradually increasing fever, headache, muscle pains, malaise, and loss of appetite that may persist for a week or more; "rose spot" rash may appear on lower chest and abdomen. Gastrointestinal symptoms common to other forms of bacterial gastroenteritis may occur. With typhoid fever, life-threatening complications are possible, including intestinal hemorrhage, perforation, kidney failure, or peritonitis (inflammation of the peritoneum). Incubation period -- 8-48 hours. Susceptibility --Travel to countries lacking adequate sanitation; contact with asymptomatic carriers. Treatment -- Fluid and electrolyte replacement are indicated for salmonellosis; antimicrobials (a combination of ceftriaxone and ciprofloxacin is recommended) are used against typhoid fever. Carriers may require removal of the gallbladder to end carrier status. Prevention -- Proper and adequate sanitation and food handling, immunization for travelers to endemic areas, and preventing carriers from working as food handlers.​

Disease at a Glance - Staphylococcal Intoxication (Food Poisoning)

Cause -- Staphylococcus aureus (facultatively anaerobic, Gram-positive cells arranged in clusters). Virulence factors -- Heat-stable enterotoxins, salt tolerance Portal of entry -- Toxin crosses mucous membranes of the intestinal tract following consumption of contaminated food; Staphylococcus is not directly involved in the disease. Signs and symptoms Nausea, vomiting, diarrhea, cramping, discomfort, bloating, loss of appetite, and fever; all lasting 24 hours or less. Incubation Period -- Four to six hours. Susceptibility -- Everyone is susceptible because the organism is a normal member of the microbiome, but intoxication results only when inoculated food is improperly refrigerated or undercooked prior to consumption. Treatment -- Self-administered replacement of fluids and electrolytes. Prevention -- Thorough handwashing before and after handling foods, cleaning utensils between use on different foods, and prompt refrigeration of leftovers all decrease risk of staphylococcal food poisoning.

Disease at a Glance - Toxoplasmosis

Cause -- Toxoplasma gondii (apicomplexans protozoan). Virulence factors -- Ability to survive inside many different types of cells in many different hosts. Portal of entry -- Ingestion in meat or inhalation of contaminated soil or cat litter. Signs and symptoms -- Most patients have no manifestations. In immunocompromised patients: fever; malaise; inflammation of lungs, liver, and heart; headache; confusion; spastic paralysis; blindness; myocarditis; encephalitis. Transplacental transfer to a fetus can cause epilepsy, mental retardation, microcephaly, inflammation of the retina and blindness, anemia, jaundice, or spontaneous abortion or stillbirth. Incubation period -- 10 to 23 days. Susceptibility -- Immunocompromised and unborn babies. Treatment -- Pyrimethamine and sulfonamides. Prevention -- Avoid contact with contaminated soil (cat litter); wash all fruits and vegetables; thoroughly cook; freeze, or smoke meat.

Disease at a Glance - Syphilis

Cause -- Treponema pallidum (spirochete). Virulence factors -- Glycocalyx, adhesins, hyaluronidase. Portal of entry -- Mucous membranes of genitalia; sexual or congenital transmission. Signs and symptoms -- Primary syphilis: hard, nonpainful genital chancre that disappears after three to six weeks. Secondary syphilis: sore throat, headache, mild fever, malaise, myalgia, and rash that lasts several weeks or months. Latent syphilis: generally asymptomatic; lasts for decades. Tertiary syphilis: dementia, blindness, paralysis, and gumma lesions. Incubation period -- 10-90 days (average 21 days) for the primary form of the disease. Susceptibility -- Sexually active individuals and fetuses whose mothers are infected. Treatment -- Penicillin. Prevention -- Sexual abstinence, mutual monogamy, or use of condoms.

Disease at a Glance- Plague

Cause -- Yersinia pestis (Gram-negative coccobacillus). Virulence factors -- Plasmids code for adhesins, type III secretion systems, capsule, and antiphagocytic proteins; endotoxin. Portal of entry -- Bubonic plague: transmitted by the bite of a flea from an infected rodent. Pneumonic plague: travels in blood to lungs; inhaled. Signs and symptoms -- Bubonic plague: buboes (painfully inflamed lymph nodes), fever, chills, malaise, muscle pain, headache, bactermia, septicemia, low blood pressure, disseminated intravascular coagulation, and death of infected tissue, which turns black. Pneumonic plague: fever, malaise, severe cough, bloody sputum, and difficulty in breathing. Untreated pneumonic plague is 100% fatal. Incubation period -- Bubonic plague: one to seven days. Pneumonic plague: one to four days, though it can be as little as a few hours. Susceptibility -- People who enter areas where Yersinia is endemic in animal populations, such as prairie dog "towns"; people exposed to others who have pneumonic plague. Treatment -- Immediate treatment with antimicrobial drugs such as streptomycin or doxycycline. Prevention -- Rodent control; avoidance of endemic areas; possible vaccine.

Disease at a Glance - Trichomoniasis

Cause Trichomonas vaginalis, a single-celled, flagellated protozoan in the taxon Parabasala. Virulence factors Adhesins, proteolytic enzymes, hemolysis, cell-detaching factor. Portal of entry Mucous membrane of genital tracts. Signs and symptoms In females: malodorous, yellow-green vaginal discharge, vaginal irritation, possibly spot bleeding, dysuria; in males: usually asymptomatic, though the disease may cause urethritis and prostatitis. Incubation period 4-28 days. Susceptibility Sexually active individuals, more commonly heterosexual than homosexual; uncircumcised males may be more at risk than are circumcised males; in pregnant women, trichomoniasis can result in low birth weight and premature birth of baby. Treatment Metronidazole or tinidazole. Prevention Abstinence, mutual monogamy of both partners, consistent and accurate condom usage

Smallpox - Disease at a Glance

Cause: -- Orthopoxvirus (variola virus) (enveloped, double-stranded DNA virus). Virulence factors: -- Intracellular infection, codes for proteins that inhibit interferon, complement, and inflammation. Portal of entry: -- Inhalation of viruses in droplets or dried crusts. Signs and symptoms: -- The prodromal period (two to four days) includes high fever, headaches and body aches, and malaise. A rash begins in the mouth and spreads to the face and downward all over the body. The rash becomes papules, then vesicles, and finally pustules. Eventually the pustules dry to form crusts. Scarring may result. Incubation period: -- Average 12 to 14 days but can range from 7 to 17 days. The person is not contagious at this stage. Susceptibility: -- Currently, there is no naturally occurring smallpox. However, if a bioterrorism event or accidental release were to occur, it is theorized that most people would be susceptible since regular vaccination was discontinued decades ago. Treatment: -- Immediate vaccination; tecovirimat; supportive therapy. Prevention: -- Routine vaccination was discontinued in most of the United States in 1972. In response to recent world events, the U.S. government ordered new production of the smallpox vaccine and is currently prepared in the event of an outbreak.

Disease at a Glance - Pseudomonas Infection

Cause: -- Pseudomonas aeruginosa (Gram-negative, aerobic, rod-shaped bacterium). Virulence factors: -- Fimbriae, adhesins, capsule, neuraminidase, elastase, endotoxin, exotoxin A, exoenzyme S, pyocyanin. Portal of entry: -- Contact with wounded skin or deeper tissues following severe burns; inhalation; healthcare-associated infections occur from Pseudomonas biofilms on endotracheal tubes. Signs and symptoms: -- Characteristic blue-green color where the bacterium is growing; fever, blood clotting, inflammation, possible shock; with lung infections: breathlessness, coughing, wheezing, rapid breathing, and weight loss. Incubation period: -- Eight hours to five days. Susceptibility: -- Burn victims, cancer patients, immunocompromised patients; cystic fibrosis patients are particularly at risk for lung infection. Treatment: -- Simultaneous use of both a semisynthetic penicillin and a sulfonamide. Prevention: -- The ubiquity of Pseudomonas in wet environments makes it nearly impossible to prevent exposure, but the bacterium does not invade intact tissue.

Disease at a Glance - Bacteremia / Endocarditis

Causes -- Numerous bacteria may cause bacteremia or endocarditis. Common opportunistic or nosocomial causes of bacteremia are Pseudomonas aeruginosa, Neisseria meningitidis, Escherichia coli, Salmonella species, Staphylococcus aureus, and Streptococcus pneumoniae. About half the cases of bacterial endocarditis are caused by viridans streptococci. Bartonella, Mycobacterium, and Mycoplasma species also cause the disease. Virulence factors -- Vary with pathogen but include attachment molecules, capsules, flagella, endotoxin, exotoxins, and antiphagocytic factors. Portal of entry -- Inoculation of bacteria into the blood via open wounds. Signs and symptoms -- Bacteremia is characterized by fever, chills, nausea, vomiting, diarrhea, shortness of breath, malaise, and confusion or an impending sense of doom. Endocarditis symptoms include fever, extreme fatigue, malaise, difficulty breathing, and tachycardia. Incubation period -- Bacteremia symptoms can occur within hours to days following infection. Acute endocarditis can develop over days to a few weeks, whereas subacute bacterial endocarditis develops more slowly, over weeks or months. Susceptibility -- People with a suppressed immune system and patients requiring regular or prolonged invasive medical procedures, such as intravenous therapy or kidney dialysis. Treatment -- Prompt treatment and identification are important. Administration of appropriate antibiotics, elimination of the initial site of infection, and intravenous fluid replacement are the proper treatment for bacteremia. Treatment for endocarditis is similar: intravenous antibiotic therapy, often for a course of six weeks. Prevention -- Patients with known risk factors may be given prophylactic antibiotics before surgeries or dental procedures. Proper sterilization of medical instruments and proper wound care are also standard preventive measures.

Disease at a Glance - Bacterial Pneumonias

Causes -- Streptococcus pneumoniae (Gram-positive diplococcus also known as pneumococcus), Mycoplasma pneumoniae (Gram-positive, but pink-staining, pleomorphic bacterium), Klebsiella pneumoniae (Gram-negative bacillus), Haemophilus influenzae (Gram-negative pleomorphic coccobacillus), Staphylococcus aureus (Gram-positive coccus), Yersinia pestis (Gram-negative rod), and Chlamydophila psittaci and C. pneumoniae (obligate intracellular pleomorphic bacteria). Virulence factors -- Vary among pathogens but include attachment molecules, capsules, inhibitors of phagocytosis, and lipid A of endotoxin. Portal of entry -- Inhalation, also via blood in case of Yersinia. Signs and symptoms -- Dry, unproductive cough, headache, fever, chills, and chest pain. Bloody mucoid sputum with Klebsiella; frothy bloody sputum with Yersinia. Incubation period -- Pneumococcus: 1-3 days; M. pneumoniae: 1-4 weeks; K. pneumoniae: 1-3 days; H. influenzae: 2-4 days; S. aureus: variable, usually days; Y. pestis: a few hours to 2 days; Chlamydophila spp.: 1-4 weeks. Susceptibility -- Pneumococcus: immunocompromised individuals; M. pneumoniae: high school and college students; K. pneumoniae: hospitalized individuals; H. influenzae: infants and young children; S. aureus: the very young and patients with respiratory diseases, such as cystic fibrosis patients; Y. pestis: people exposed to bubonic plague; C. pneumoniae: most common in school-aged children; C. psittaci: individuals in close contact with birds. Treatment -- Pneumococcus: penicillin G, vancomycin; Mycoplasma: a macrolide or tetracycline; K. pneumoniae: cephalosporin; H. influenzae: amoxicillin, cephalosporin; S. aureus: nafcillin, oxacillin, cloxacillin, dicloxacillin, vancomycin; Y. pestis: streptomycin, gentamicin; Chlamydophila spp.: erythromycin, tetracycline. Prevention -- Use general precautions, such as washing hands frequently. Stop smoking, and, in the case of C. psittaci, avoid infected birds. Vaccines against S. pneumoniae and H. influenzae are available.

Review - What causes cell damage in a type III hypersensitivity? A. Basophils release chemicals that damage nearby tissues. B. Antigen-antibody complexes damage the cells near where they deposit. C. Complement proteins make holes in the cells. D. Chemicals released by neutrophils

Chemicals released by neutrophils damage tissues where antigen-antibody complexes are lodged

3 clinical forms of leishmaniasis

Cutaneous leishmaniasis - large, painless skin ulcers that form around bite wounds made by the disease vector - lesions often become secondarily infected with bacteria - scar remains when vectors heal - not fatal Mucocutaneous leishmaniasis - results when skin lesions enlarge to encompass the mucous membranes of the mouth, nose, or soft palate - Damage is severe and permanently disfiguring - not fatal Visceral leishmaniasis - AKA "kala-azar" - typically fatal in 100% of untreated cases - macrophages spread the parasite to the liver, spleen, bone marrow, and lymph nodes - Inflammation, fever, weight loss, and anemia increase in severity as the disease progresses - becoming increasingly problematic as an opportunistic infection among AIDS patients

HIV directly infects T-cells. Why is this problematic for cell-mediated immunity? - HIV causes cytokines to be produced at much higher levels, altering the normal function of the immune system. - HIV transforms the T-cells into cancer cells. - HIV reprograms these cells to attack the body cells. - Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.

Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.

Review - How is histoplasmosis transmitted? A. By spores entering wounds from contaminated soil. B. By inhalation of spores from desert soil. C. By spores that directly contact the skin. D. By inhalation of spores from bird or at droppings.

D

Review - What is cystitis? A. Inflammation of the prostate. B. Inflammation of the kidneys. C. Inflammation of the urethra. D. Inflammation of the bladder.

D

Review - What is the best way to prevent pneumococcal pneumonia? A. Protection against exposure to respiratory droplets. B. Giving prophylactic penicillin to high-risk patients. C. Good hand hygiene. D. Immunization.

D

Review - What is the best way to prevent schistosomiasis? A. Avoiding blood transfusions. B. Immunization. C. Preventing insect bites. D. Sewage treatment and avoiding contaminated water

D

Review - What is the name of small hemorrhagic skin lesions that are a sign of bacteremia? A. Lymphangitis. B. Toxemia. C. Septicemia. D. Petechiae.

D

Review - What is unique about Streptococcus pyogenes strains that cause scarlet fever? A. They have M protein, which inhibits complement proteins. B. They have Lancefield antigens. C. They have flagella. D. They carry a lysogenic bacteriophage.

D

Review - Which form of gastroenteritis is the most common reason people seek medical attention? A. Shigellosis. B. Pseudomembranous colitis. C. Typhoid fever. D. Campylobacter diarrhea.

D

Review - Which phase of syphilis presents with a rash, which may be on the palms of the hands and the soles of the feet? A. The latent phase. B. The primary phase. C. The tertiary phase. D. The secondary phase.

D

Review - Why is it necessary to test for beta-hemolytic streptococcal strains to diagnose strep throat? A. To determine the best antibiotics to use against the infection. B. Because Gram stains aren't accurate enough to identify the causal agent of strep throat. C. To determine whether the strain has the pyrogenic toxin that can lead to scarlet fever. D. Because streptococcal bacteria are abundant normal microbiota in respiratory samples.

D

How do medical personnel confirm a diagnosis of cat scratch disease? A. Gram stain to confirm the presence of Gram-negative bacilli. B. Presence of vesicles on the skin after the patient has been scratched by a cat. C. Visual observation. D. An indirect fluorescent antibody test.

D - A positive indirect fluorescent antibody test is used to confirm cat scratch disease.

Review - Which bacterial pathogen infects neutrophils and replicates inside phagosomes? A. Ehrlichia chaffeensis. B. Borrelia burgdorferi. C. Yersinia pestis. D. Anaplasma phagocytophilum.

D - Anaplasma phagocytophilum infects neutrophils and replicates inside phagosomes. - Yersinia pestis injects antiphagocytic proteins into dendritic cells, neutrophils, and macrophages, preventing phagocytosis.

Review - How can the bacteria that cause dental caries invade teeth? A. They have specialized structures that can invade the hardened teeth enamel. B. Teeth have tiny pores through which bacteria can gain access to the dentin underneath the tooth enamel and the pulp on the inside. C. They produce degradative enzymes that break down tooth enamel. D. They produce acid, which dissolves tooth enamel, giving bacteria access to dentin and the pulp inside it.

D - Bacteria that cause dental caries ferment sugars to produce acid, which damages teeth, allowing the bacteria to invade.

Review - What role does cord factor play in the virulence of Mycobacterium tuberculosis? A. It increases resistance to antibiotics. B. It makes mycobacteria divide faster, decreasing the generation time. C. It enables intracellular bacterial growth. D. It inhibits migration of neutrophils.

D - Cord factor inhibits migrations of neutrophils and is toxic to mammalian cells.

Review - What is the term used for viruses of eukaryotes that can remain in a cell for years without replicating until they are reactivated? A. Stasis. B. Persistence. C. Lysogeny. D. Latency.

D - Latent viruses can remain in the chromosomes of cells for an extended period of time. Latent viruses can remain inside the cell for an extended period of time without replicating until they are reactivated at a later date.

Review - What causes the black color of tissues with gas gangrene? A. Congealed and clotted blood. B. In large numbers, Clostridium perfringens appears black. C. The bacteria produce a black gas. D. Cell death.

D - Necrosis is the death of tissues; necrotic tissues appear black.

Review - People with what trait have hemoglobin S, which makes them resistant against malaria? A. Lack of Duffy antigens. B. Glucose-6-phosphate dehydrogenase deficiency. C. Hemoglobin C. D. Sickle-cell trait.

D - People with sickle-cell trait have hemoglobin S, which makes the red blood cells less susceptible to infection by Plasmodium.

Review - How does pertussis toxin result in an increase of infected cells? A. It attracts additional Bordetella pertussis bacteria through chemotaxis. B. It increases the ability of the Bordetella pertussis bacteria to divide. C. It causes the characteristic whooping cough that takes the bacteria from the upper respiratory tract to the lower respiratory tract. D. It causes cells to synthesize more receptors to which the Bordetella pertussis bacteria can attach.

D - Pertussis toxin induces cells to produce more receptors for B. pertussis bacteria, increasing the number of infected cells.

Review - What structure do spirochetes use for motility? A. Peritrichous flagella. B. Fimbriae. C. Cilia. D. Axial filament.

D - Spirochetes use their axial filaments for motility. Spirochetes (flexible, spiral-shaped bacteria) have axial filaments, which are bundles of flagella that wrap around the bacterium between its cell wall and its outer membrane. This allows the bacteria to move in a corkscrew-like fashion.

Review - What characteristic of Staphylococcus spp. allows them to grow on the surface of the skin? A. They are smaller and can therefore hide better in skin crevices. B. They are alkalinophiles. C. They are mesophiles. D. They are halotolerant.

D - Staphylococcus spp. are halotolerant and can therefore grow on the surface of the skin, where the salt concentration is relatively high.

Review - How are the bloodstream and the lymphatic system different? A. The bloodstream contains cells, whereas lymph is fluid without any cells. B. The bloodstream consists of vessels, whereas lymph flows freely between the body's cells and organs. C. The bloodstream branches, whereas the lymphatic system does not. D. The bloodstream is a closed system, whereas the lymphatic system is open.

D - The bloodstream is a closed system, meaning that blood travels both to and from the heart. The lymphatic system, in contrast, is open: lymph travels only one way.

Review - Which type of leishmaniasis can be fatal? A. Mucocutaneous leishmaniasis. B. Cutaneous leishmaniasis. C. Lymphocutaneous leishmaniasis. D. Visceral leishmaniasis.

D - Visceral leishmaniasis can spread to the liver, spleen, bone marrow, or lymph nodes and is 100% fatal if left untreated.

Which of the following are likely to be found on an MHC-I protein? - Membranes from a neighboring dead host cell - Bacterial flagella - Damaged mitochondrial fragment - Bacterial DNA - Bacterial cell wall fragment

Damaged mitochondrial fragment

Review - Chronic granulomatous disease

Defect: Ineffective phagocytes Manifestation: Uncontrolled infections

Review - Bruton-type agammaglobulinemia

Defect: Lack of B cells and thus lack of immunoglobulins Manifestation: Overwhelming bacterial infections

Review - DiGeorge syndrome

Defect: Lack of T cells and thus no cell- mediated immunity Manifestation: Overwhelming viral infections

Failure of thymus development may result in: - DiGeorge syndrome. - Bruton-type agammaglobulinemia. - type I diabetes. - Grave's disease. - chronic granulomatous disease

DiGeorge syndrome

Two categories of immune testing

Direct testing - Looking for presence of antigens Indirect testing - Look for antibodiesthat have formed against antigens ***Test chosen based on the suspected diagnosis, cost, and speed with which a result can be obtained

What bonds link the heavy and light chains together?

Disulfide bonds, which are covalent bonds between sulfur atoms in adjoining amino acids

Attachment of HIV

HIV primarily attaches to four kinds of cells: helper T cells; cells of the macrophage lineage, including monocytes, macrophages, and microglia (special phagocytic cells of the central nervous system); smooth muscle cells, such as those in arterial walls; and dendritic cells. HIV can also rarely infect nerve cells, liver cells, and some epithelial cells. Additionally, B lymphocytes attach to HIV that has been covered with complement proteins. Though HIV does not infect these B cells, the B cells deliver HIV to helper T cells, which then become infected. Similarly, infected macrophages can pass HIV to helper T cells.

Review - How is Rickettsia rickettsii transmitted? A. Entry through open wounds. B. Contact with contaminated soil. C. Direct person-to-person contact. D. Through tick bites.

Hard ticks transmit R. rickettsii when they bite their hosts.

What is the role of helper T cells in the adaptive immune response? - Helper T cells produce and secrete antibodies. - Helper T cells phagocytize bacteria and viruses. - Helper T cells directly kill infected host cells. - Helper T cells activate B cells and cytotoxic T lymphocytes to kill infected host cells.

Helper T cells activate B cells that are displaying antigen, causing clonal expansion. Helper T cells also activate cytotoxic T cells, which will search for and destroy infected host cells.

Plasmodium Life Cycle

Liver phase (exoerythrocytic phase)(in humans) steps 1-3 Erythrocytic Cycle (in humans) steps 4-8 1. A female Anopheles mosquito injects sporozoites into the human during a blood meal 2. Sporozoites travel through the bloodstream, invade liver cells, and undergo schizogony 3. Generally, two weeks later, the liver cells rupture and release 30k-40k merozoites into the blood. The liver is damaged. 4. Free merozoites penetrate erythrocytes 5. A merozoite becomes a trophozoite, shown in its ring state below 6. Trophozoites undergo schizogony to produce merozoites, which are released when the erythrocytes break open. This occurs simultaneously and cyclically every 48-72 hours depending on the species of Plasmodium. The damaged liver cannot effectively process the amount of hemoglobin released, leading to jaundice. 7. Some merozoites develop into male and female gametocytes within erythrocytes. 8. Released merozoites adhere to and then infect new erythrocytes.

Review - Type 2

Name: Cytotoxic hypersensitivity Cause: Antibodies and complement lyse target cells Time Course: Minutes to hours Characteristic Cells Involved: Plasma cells secrete antibodies that act against other body cells

Review - Type 4

Name: Delayed (cell-mediated) hypersensitivity Cause: T cells attack the body's cells Time Course: Several days Characteristic Cells Involved: Activated T cells

Review - Type 1

Name: Immediate hypersensitivity Cause: Antibody (such as IgE) on sensitized cells' membranes binds antigen, causing degranulation Time Course: After initial sensitization, seconds to minutes Characteristic Cells Involved: Previously sensitized mast cells or basophils

Review - Type 3

Name: Immune complex-mediated hypersensitivity Cause: Nonphagocytized complexes of antibodies and antigens trigger complement activation, leading to inflammation, and cause neutrophils to release damaging enzymes Time Course: Several hours Characteristic Cells Involved: Neutrophils

Which of the following is NOT a step used by cytotoxic T cells to kill infected host cells? - Secretion of granzyme - Recognition of infected host cell using its TCR - Recognition of infected host cell using its CD4 glycoprotein - Secretion of perforin

Recognition of infected host cell using its CD4 glycoprotein - The cytotoxic T cell uses its CD8 glycoprotein to bind to the MHC-I of an infected host cell.

Why did the skin turn red and swell up? - Redness and swelling are due to the release of histamine during degranulation of mast cells and basophils. - Redness and swelling are due to the release of antihistamine during degranulation of mast cells and basophils. - Redness and swelling are due to the release of IgG from plasma cells. - Redness and swelling are due to the release of IgE from mast cells.

Redness and swelling are due to the release of histamine during degranulation of mast cells and basophils. - Histamine release causes increased vascular permeability and irritation

Details of Synthesis and Latency of HIV

Reverse transcriptase, which was carried inside the capsid, becomes active in the cytosol and transcribes dsDNA from the ssRNA genome of the virus in three nearly simultaneous steps, as shown in FIGURE 18.17. First, the enzyme synthesizes a negative single-stranded DNA (ssDNA) copy of the viral ssRNA, forming a ssDNA-ssRNA hybrid. It uses tRNA, which is also carried inside the viral capsid, as a primer ❶❶. The enzyme then degrades the ssRNA of the hybrid to leave ssDNA ❷❷ and, finally, synthesizes a complementary positive strand of DNA, thereby completing the process of forming dsDNA ❸❸. Reverse transcriptase is very error prone, making about five errors per genome. This generates multiple antigenic variations of HIV. Billions of variants may develop in a single patient over the course of the syndrome. HIV is a latent virus. The dsDNA made by reverse transcriptase is known as a provirus, and it enters the nucleus. A viral enzyme known as integrase inserts the dsDNA provirus into a human chromosome. Once integrated, the provirus permanently remains part of the cellular DNA. It may remain dormant for years or be activated immediately, depending on its location in the human genome and the availability of promoter DNA sequences (see Figure 7.9). Infected macrophages and monocytes are major reservoirs of integrated HIV, and they serve as a means of distributing the virus throughout the body. An infected cell replicates integrated DNA every time cellular DNA is replicated. In this way, HIV ends up infecting all progeny of infected cells. An infected cell may also transcribe integrated HIV to make viral messenger RNA molecules as well as entire RNA copies of the whole HIV genome.

Which of the following could result in hemolytic disease of the newborn? - either Rh-positive mother and Rh-negative father or Rh-negative mother and Rh-positive father - Rh-positive mother and Rh-positive father - Rh-positive mother and Rh-negative father - Rh-negative mother and Rh-positive father - Rh-negative mother and Rh-negative father

Rh-negative mother and Rh-positive father

Which of the following statements about T lymphocytes is FALSE? - T lymphocytes have TCRs that recognize antigen only if it is bound to MHC. - T lymphocytes produce antibody molecules. - There are three types of T lymphocytes. - T lymphocytes directly attack cells and produce the cell-mediated immune response. - T lymphocytes are called such because they mature in the thymus.

T lymphocytes produce antibody molecules

How do lymphocytes develop receptors complementary to normal body components (autoantigens)?

T lymphocytes randomly generate the variable region shapes of their TCRs - It is vitally important that adaptive immune responses not be directed against autoantigens - When self-tolerance is impaired, the result is an autoimmune disease

HHV-2

Usual Diseases: 85% of genital herpes cases Mode of Transmission: Sexual intercourse Site of Latency: Sacral ganglia Location of Lesions: External genitalia and, less commonly, thighs, buttocks, and anus Other Complications: 10% of oral herpes cases; 70% of neonatal herpes cases

Characteristics of Some Viral Hemorrhagic Fevers: Yellow Fever

Viral Genus (Family): Flavivirus (Flaviviridae) Natural Host(s): Humans, monkeys Vector: Aedes aegypti mosquito Geographical Distribution: Africa, South America

Characteristics of Some Viral Hemorrhagic Fevers: Dengue

Viral Genus (Family): Flavivirus (Flaviviridae) Natural Host(s): Humans, monkeys Vector: Aedes aegypti mosquito Geographical Distribution: Worldwide, especially tropics

Characteristics of Some Viral Hemorrhagic Fevers: Lassa

Viral Genus (Family): Lassa (Arenaviridae) Natural Host(s): African soft-furred mouse Vector: None Geographical Distribution: Central West Africa

Characteristics of Some Viral Hemorrhagic Fevers: Marburg

Viral Genus (Family): Marburgvirus (Filoviridae) Natural Host(s): Probably bats Vector: None Geographical Distribution: Central Africa, research facility in Europe

Review - What is the cause of repeated herpes outbreaks in a patient over the years? A. Repeated exposures to new viruses over the years. B. The body's adaptive immune response breaks down over time, allowing repeated outbreaks. C. Viral latency. D. Viral persistence.

Viral latency - Herpesviruses are latent, meaning that they can remain inactive within cells and reactivate at a later date

An individual may be made immune to an infectious disease by two artificial methods:

active immunization - which involves administering antigens to a patient so that the patient actively mounts an adaptive immune response passive immunotherapy - in which a patient acquires temporary immunity through the transfer of antibodies formed by other individuals or animals

A person who has been exposed to rabies receives both HRIG (human rabies immunoglobulin) injected near the bite site and the rabies vaccine. What does this strategy represent? - passive immunotherapy - viral hemagglutination inhibition - active immunization - passive immunotherapy combined with viral hemagglutination inhibition - active immunization combined with passive immunotherapy

active immunization combined with passive immunotherapy

Review - What is the greatest risk of a flu shot? A. An allergic response to egg proteins. B. Paralysis. C. The patients can get the flu. D. Development of neurological disorders.

allergic response to egg proteins - Influenzavirus is grown in eggs, so the immunization may have some egg proteins. If a patient is allergic to eggs, the immunization can cause an allergic reaction.

Review - If someone receives a tetanus vaccine, what type of immunity results (artificial/natural, active/passive)? A. Natural passive immunity B. Natural active immunity C. Artificial active immunity D. Artificial passive immunity

artificial active immunity - This is an example of artificial immunity because the antigen is injected intentionally. It is a form of active immunity because the person who is exposed to the antigen produces an immune response. Injecting an antigen is a form of artificial immunity. The resulting immune response is carried out by the individual injected, so this is an active immune response.

A physician wants to stimulate immunological memory in a patient. Which of the following types of immunity would be the most useful? - artificially acquired passive immunity - naturally acquired passive immunity - artificially acquired active immunity - naturally acquired active immunity

artificially acquired active immunity

Contact immunity within a population can be produced by ________ vaccines. - attenuated - subunit - inactivated - DNA - toxoid

attenuated

Vegetations

bulky masses of platelets and clotting proteins that surround and bury the bacteria of endocarditis, hiding them from defensive cells, antibodies, and antimicrobial drugs

Which type of cell directly attacks infected cells? - Cancerous cells - Helper T-cells - Cytotoxic T-cells - Bacterial cells

cytotoxic t cells

brequinar sodium and leflunomide - cytotoxic drugs

each of which inhibits pyrimidine synthesis and thereby inhibits cellular replication

type 2 helper T cells (Th2 cells)

function in conjunction with B cells

Fever is beneficial during viral infection because the higher temperature: - increases vasodilation, contributing to inflammation. - prevents viral infection of fibroblasts. - inactivates interferons. - increases sweating and consequently the barrier effect. - increases the effectiveness of interferons.

increases the effectiveness of interferons

Mucous membranes are a part of - innate defense. - the complement system. - cell-mediated immunity. - humoral immunity. - adaptive defense

innate defense

The student who caught the cold caused by this specific Rhinovirus was exposed to the exact same Rhinovirus 18 months later. What component of the immune system will protect her from getting the same cold again? - Antibodies that are "left over" from the last infection - Dendritic cells - Memory B cells - Plasma cells

memory B cells - Memory cells to that specific virus are stored in the lymph nodes for many years. When the student comes into contact with this specific Rhinovirus, these memory cells quickly divide and differentiate into antibody-producing plasma cells. The antibodies will prevent the virus from reaching an infectious titer (number that causes infection).

fibrous tunic

outer wall of the eye - provides a tough barrier against the penetration of microbes

Review - Which creates a faster immune response, active immunization or passive immunotherapy?

passive immunotherapy

High doses or multiple dosing of inactive vaccines can increase the risk of what?

producing allergies

Apoptosis is the process of __________. - differentiating into a regulatory T cell - presenting epitope in an MHC protein - programmed cell death - multiplying into a clone repertoire

programmed cell death - T cells that undergo apoptosis commit suicide and are deleted from the immune cell population

Portal of Entry of Chickenpox and Shingles

respiratory tract

The phenomenon known as chemotaxis is defined as: - the movement of a cell toward or away from a chemical stimulus. - an increase in allergies and helminth infection. - the coating of a pathogen by complement. - the squeezing of cells through the lining of capillaries. - the release of prostaglandins and leukotrienes in response to microbes

the movement of a cell toward or away from a chemical stimulus.

Antibody adaptive immunity involves:

the secretion of specific antibodies that have a variety of functions - T-dependent antibody immune response occurs when an APC binds to a specific Th cell and signals the Th cell to proliferate

Salmonellosis and Typhoid Fever - points from book

❶ Salmonella is ingested in contaminated water or food, particularly chicken eggs. ❷ Bacterium passes through the stomach, attaches to cells lining the small intestine, and induces endocytosis. ❸ The pathogen eventually kills host cells. ❹ This triggers fever, abdominal cramps, and diarrhea. ❺ Cells of serotype Typhi can subsequently enter the blood, where they are phagocytized but not digested. ❻ Phagocytes carry Salmonella serotype Typhi to the liver, spleen, bone marrow, and gallbladder. ❼ Salmonella serotype Typhi can establish semipermanent infection in the gallbladder. Carriers can remain infected for years even with treatment. ❽ Salmonella is shed in feces.​