BIOS 350 Ch 15 Wk 11 Exam 4

exposure

first stage of the 4 stages of pathogenesis, before adhesion Encounter with a potential pathogen Food we eat and objects we handle can lead to this

virulence factors

Determine extent and severity of diseases individual pathogens may cause Pathogen's factors encoded by genes that can be identified using molecular Koch's postulates.

a. true (kahoot #40)

Diphtheria toxin inhibits protein synthesis, causing cellular death. a. True b. False

iatrogenic disease

Disease that is contracted as the result of a medical procedure. Can occur after procedures involving wound treatments, catheterization, or surgery if the wound or surgical site becomes contaminated.

b. Iatrogenic diseases (Kahoot #32)

Diseases that are contracted as the result of a medical procedure are known as a. Nosocomial diseases b. Iatrogenic diseases c. Infectious diseases d. Zoonotic diseases

iatrogenic (KC Wk 11 Q10)

During an oral surgery, the surgeon nicked the patient's gum with a sharp instrument. This allowed Streptococcus, a bacterium normally present in the mouth, to gain access to the blood. As a result, the patient developed bacterial endocarditis (an infection of the heart). Which type of disease is this? vehicle communicable iatrogenic zoonotic

Proteases

An exoenzyme that degrades collagen in connective tissue to promote spread Collagenase in Clostridium perfringens

local infection

A type of infection confined to a small area of the body, typically near the portal of entry

toxin

biological poisons that assist in their ability to invade and cause damage to tissues.

most common body's portals of exit

skin and the respiratory, urogenital, and gastrointestinal tracts.

noninfectious disease

-any disease not caused by pathogens -i.e. certain types of genetic disorders

Exotoxins

-protein molecules that are produced by a wide variety of living pathogenic bacteria. -Mostly gram positive bacteria and gram negative -usually heat-labile (not heat stable) proteins secreted by certain species of bacteria which diffuse into the surrounding medium -highly toxic -can target liver cells

mucosal surfaces

1 of the body's portals of entry most important portal for microbes and include mucous membranes of the respiratory tract, the gastrointestinal tract, and the genitourinary tract most of these are in the interior of the body, some are contiguous with the external skin at various body openings, including the eyes, nose, mouth, urethra, and anus.

the 4 steps of Koch's postulates

1. The suspected pathogen must be found in every case of disease and not be found in healthy individuals. 2. The suspected pathogen can be isolated and grown in pure culture. 3. A healthy test subject infected with the suspected pathogen must develop the same signs and symptoms of disease as seen in postulate 1. 4. The pathogen must be re-isolated from the new host and must be identical to the pathogen from postulate 2.

M protein

Aids in immune system evasion by altering the surface of Streptococcus and inhibits phagocytosis by blocking the binding of the complement molecules that assist phagocytes in ingesting bacterial pathogens

respiratory and GI tracts

2 of the body's vulnerable portals of entry b/c particles that include microorganisms are constantly inhaled or ingested, respectively 2 different tracts

c. and d. communicable and contagious diseases (Kahoot #31)

31. Diseases which can be spread from person to person are called a. Iatrogenic diseases b. Nosocomial diseases c. Communicable diseases d. Contagious diseases

capsules

Aids in immune system evasion by preventing ingestion by phagocytes Composition of this prevents immune cells from adhering and then phagocytose to the cell Makes bacterial cell larger making it harder for immune cells to engulf pathogen

d. contagious (practice exam #6)

A communicable disease that can be easily transmitted from person to person is which type of disease? a. nosocomial b. acute c. iatrogenic d. contagious

placental (KC Week 11 Q4)

A mother contracts German measles while pregnant. The baby is born with deafness due to the virus. Which portal of entry did the pathogen use to infect the baby? vagina conjunctiva parenteral placental

syndrome

A specific group of signs and symptoms characteristic of a particular disease

c. the ability to adhere to cells of the body (practice exam #7)

A strain of Neisseria gonorrhea has a mutation which has caused it to lose the ability to produce functional fimbriae and has become less virulent as a consequence. What function has this pathogen lost? a. the ability to prevent phagocytes killing its ability to prevent phagocytes killing it b. the ability to establish a latent infection c. the ability to adhere to cells of the body d. the ability to produce an endotoxin e. the ability to resist antibiotics

Spike proteins in the envelope of HIV. (practice exam #8)

All are bacterial virulence factors except: A protease enzyme that breaks down antibodies. The coagulase enzyme released by certain Gram positive microbes. Spike proteins in the envelope of HIV. A capsule.

tetanus neurotoxin

An exotoxin that has light A and heavy B chains Toxin binds to inhibitory interneurons which are responsible for releasing GABA and glycine Inhibits release of glycine and GABA from interneuron which results in permanent muscle contraction muscle spasms in other body parts and culminate with respiratory failure and death

b. False (Kahoot #41)

Antigenic drift is a major change in spike proteins due to gene reassortment. a. True b. False

septicemia (KC Week 11 Q5)

Bacteria are actively colonizing the blood. This is known as: septicemia viremia bacteremia toxemia

zoonotic disease

Certain infectious diseases are not transmitted between humans directly but can be transmitted from animals to humans.

d. parenteral route (practice exam #9)

Chagas' disease is transmitted by a bug with mouthparts that penetrate blood vessels. Which type of portal of entry does this represent? a. mucous membrane portal b. skin c. conjunctiva portal d. parenteral route

Phospholipases

Exotoxins that degrade phospholipids of cell membranes Target membrane that encloses phagosome in phagocytic cells

Streptolysin

Exotoxins/proteins that assemble into pores in cell membranes, disrupting their function and killing the cell

vehicles for a pathogen to leave the body

Feces, urine, semen, vaginal secretions, tears, sweat, and shedding skin cells

illness (Ch 15 #15)

Fill in the blank: A difference between an acute disease and chronic disease is that chronic diseases have an extended period of __________.

noncommunicable (Ch 15 #16)

Fill in the blank: A person steps on a rusty nail and develops tetanus. In this case, the person has acquired a(n) __________ disease.

focal (Ch 15 #19)

Fill in the blank: A(n) __________ infection is a small region of infection from which a pathogen may move to another part of the body to establish a second infection.

opportunistic (Ch 15 #17)

Fill in the blank: A(n) __________ pathogen causes disease only when conditions are favorable for the microorganism because of transfer to an inappropriate body site or weakened immunity in an individual.

surface, proteins, sugars (Ch 15 #22)

Fill in the blank: Adhesins are usually located on __________ of the pathogen and are composed mainly of __________ and __________.

shift, drift (Ch 15 #24)

Fill in the blank: Antigenic __________ is the result of reassortment of genes responsible for the production of influenza virus spike proteins between different virus particles while in the same host, whereas antigenic __________ is the result of point mutations in the spike proteins.

protease, phospholipase (Ch 15 #25)

Fill in the blank: Candida can invade tissue by producing the exoenzymes __________ and __________.

adhesion (Ch 15 #20)

Fill in the blank: Cilia, fimbriae, and pili are all examples of structures used by microbes for __________.

local infection (example Q from lecture)

Fill in the blank: Pathogen A's portal of entry is the skin and it only grows near that portal of entry. Which type of infection is this? ________________

primary infection (example Q from lecture)

Fill in the blank: Person A contracts foodborne illness and recovers after a few days and is just fine. Which type of infection is this? _____________

protein synthesis (Ch 15 #23)

Fill in the blank: The Shiga and diphtheria toxins target __________ _________ in host cells.

LD50 (Ch 15 #18)

Fill in the blank: The concentration of pathogen needed to kill 50% of an infected group of test animals is the __________.

CD4 (Ch 15 #21)

Fill in the blank: The glycoprotein adhesion gp120 on HIV must interact with __________ on some immune cells as the first step in the process of infecting the cell.

a. True (Kahoot #34)

ID50 is the number of pathogen cells or virions required to cause active infection in 50% of inoculated animals. a. True b. False

capsule (Ch 15 #13)

Which of the following is a major virulence factor for the fungal pathogen Cryptococcus? hemolysin capsule collagenase fimbriae

a. True (Kahoot #35)

LD50 is the number of pathogen cells or amount of toxin required to kill 50% of infected animals. a. True b. False

A. diptheria toxin B. cholera toxin C. superantigen D. botulism toxin (KC Week 11 Q6)

Match the following: Blocks elongation factor 2 stopping translation. Disrupts intestinal osmotic balance leading to severe diarrhea. Stimulates an overactive response by the immune system leading to a cytokine storm. Neurotoxin leading to flaccid paralysis. A. diptheria toxin B. cholera toxin C. superantigen D. botulism toxin E. tetanus toxin F. membrane disrupting toxin

Tetanus is not a communicable disease. (KC Week 11 Q2)

On Memorial Day you were visiting your cousin's house and while walking barefoot in the basement cut yourself on a rusty piece of metal. Your mother says, "I hope you don't get tetanus and spread it to everyone else!" How would you answer her? Tetanus is not a communicable disease. Tetanus is a zoonotic disease. Tetanus is a noninfectious disease. Tetanus is an iatrogenic disease.

Pathogen B (KC Week 11 Q3)

Pathogen A has a high ID50 while pathogen B has a low ID 50. Which pathogen is considered more virulent? Both Pathogen A and B are considered equally virulent Pathogen B Pathogen A There is not enough information to determine virulence.

pathogen A (Ch 15 #7)

Pathogen A has an ID50 of 50 particles, pathogen B has an ID50 of 1,000 particles, and pathogen C has an ID50 of 1 × 106 particles. Which pathogen is most virulent? pathogen A pathogen B pathogen C

b. False (Kahoot #33)

Period of illness is when the host begins to experience general signs and symptoms of illness. a. True b. False

degrade cell membranes to allow pathogens to escape phagosomes (Ch 15#12)

Phospholipases are enzymes that do which of the following? degrade antibodies promote pathogen spread through connective tissue. degrade nucleic acid to promote spread of pathogen degrade cell membranes to allow pathogens to escape phagosomes

a. true (kahoot #38)

Septicemia is when the bacteria are both present and multiplying in the blood. a. True b. False

True (KC Week 11 Q8)

Several different strains of the influenza virus are replicating inside the same host. This can lead to an antigenic shift. True False

b. tetanus toxin (Kahoot #39)

The following toxin inhibits the release of inhibitory neurotransmitters in the CNS. a. Cholera toxin b. Tetanus toxin c. Botulinum toxin d. Streptolysin

Human immunodeficiency virus (Ch 15 #6)

Which of the following is a pathogen that could not be identified by the original Koch's postulates? Staphylococcus aureus Pseudomonas aeruginosa Human immunodeficiency virus Salmonella enterica serovar Typhimurium

protease (Ch 15 #26)

The larval form of Schistosoma mansoni uses a __________ to help it gain entry through intact skin.

endotoxin

The lipopolysaccharide (LPS) found on the outer membrane of gram-negative bacteria Lipid A responsible for the toxic properties of the LPS molecule lipid A triggers the immune system's inflammatory response high concentrations of this in the blood can cause an excessive inflammatory response, leading to a severe drop in blood pressure, multi-organ failure, and death. Low concentrations of these→ the inflammatory response may provide the host an effective defense against infection heat stable

c. Systemic infection (kahoot #37)

When an infection becomes disseminated throughout the body, we call it a a. Focal infection b. Primary infection c. Systemic infection d. Secondary infection

It acts as a spreading factor. (Ch 15 #11)

Which of the following applies to hyaluronidase? It acts as a spreading factor. It promotes blood clotting. It is an example of an adhesin. It is produced by immune cells to target pathogens.

exposure, adhesion, invasion, infection (Ch 15 #8)

Which of the following choices lists the steps of pathogenesis in the correct order? invasion, infection, adhesion, exposure adhesion, exposure, infection, invasion exposure, adhesion, invasion, infection disease, infection, exposure, invasion

food poisoning due to a preformed bacterial toxin in food (Ch 15 #2)

Which of the following is an example of a noncommunicable infectious disease? infection with a respiratory virus food poisoning due to a preformed bacterial toxin in food skin infection acquired from a dog bite infection acquired from the stick of a contaminated needle

b. Superantigen toxin. (practice exam #11)

Which of the following is an exotoxin that leads to an overproduction of immune system cytokines? a. Lipid A toxin. b. Superantigen toxin. c. Diptheria toxin d. Cholera toxin.

d. none of the above (kahoot #36)

Which of the following is not a stage of pathogenesis? a. Exposure b. Adhesion c. Infection d. None of the above

incubation, prodromal period, illness, decline, convalescence (KC Wk 11 Q9)

Which of the following is the CORRECT sequence of a disease process? incubation, prodromal period, illness, decline, convalescence prodromal period, convalescence, incubation, illness, decline convalescence, incubation, prodromal period, illness, decline incubation, convalescence, prodromal period, illness, decline illness, convalescence, incubation, prodromal period, decline

Plasmodium (Ch 15 #14)

Which of the following pathogens undergoes antigenic variation to avoid immune defenses? Candida Cryptococcus Plasmodium Giardia

fever (Ch 15 #1)

Which of the following would be a sign of an infection? muscle aches headache fever nausea

a surface protein allowing the pathogen to bind to host cells (Ch 15 #9)

Which of the following would be a virulence factor of a pathogen? a surface protein allowing the pathogen to bind to host cells a secondary host the pathogen can infect a surface protein the host immune system recognizes the ability to form a provirus

prodromal (Ch 15 #4)

Which period is the stage of disease during which the patient begins to present general signs and symptoms? convalescence incubation illness prodromal

kinase (KC Week 11 Q7)

Which virulence factor will dissolve fibrin clots allowing the pathogen to escape? M protein kinase antigenic variation coagulase

a. chronic (Practice exam #10)

You are studying an emerging pathogen. You discover that patients have been infected up to twenty years previously with the pathogen though they did not develop signs and symptoms until recently. Upon further analysis you note that their major organ systems have been slowly damaged by the pathogen over time. You will document this pathogen as causing which type of infection? a. chronic b. latent c. zoonotic d. acute

feeling achy (KC Week 11 Q1)

You fear that you are coming down with influenza. You have a fever of 103, a congested cough, a runny nose, and feel achy all over. Which of those is considered a symptom? congested cough feeling achy fever of 103 runny nose

exotoxin (Ch 15 #10)

You have recently identified a new toxin. It is produced by a gram-negative bacterium. It is composed mostly of protein, has high toxicity, and is not heat stable. You also discover that it targets liver cells. Based on these characteristics, how would you classify this toxin? superantigen endotoxin exotoxin leukocidin

Cryptococcus

a fungal virulence factor that causes pneumonia and meningitis, Capsule polysaccharide glucuronoxylomannan is principal constituent of Cryptococcus capsule. encapsulated Cryptococcus cells are more resistant to phagocytosis than nonencapsulated Cryptococcus, which are effectively phagocytosed and, therefore, less virulent.

Claviceps purpurea

a fungal virulence factor that grows on rye and related grains produces mycotoxin called ergot toxin (alkaloid responsible for the disease known as ergotism) two forms of ergotism: gangrenous and convulsive gangrenous ergotism- ergot toxin causes vasoconstriction, resulting in improper blood flow to the extremities, eventually leading to gangrene. convulsive ergotism- the toxin targets the central nervous system, causing mania and hallucinations.

Giardia lamblia

a protozoan virulence factor that causes the intestinal disease giardiasis uses a large adhesive disc composed of microtubules to attach to the intestinal mucosa During adhesion, the flagella moves in a manner that draws fluid out from under the disc, resulting in an area of lower pressure that facilitates adhesion to epithelial cells. does not invade the intestinal cells but rather causes inflammation and shortens the intestinal villi, inhibiting absorption of nutrients.

Trypanosoma brucei

a protozoan virulence factor that's the causative agent of African sleeping sickness include the abilities to form capsules and undergo antigenic variation evades phagocytosis by producing a dense glycoprotein coat that resembles a bacterial capsule

Plasmodium falciparum

a protozoan virulence factor that's the causative agent of malaria resides inside red blood cells produces an adhesin membrane protein known as PfEMP1. PfEMP1 is expressed on the surface of the infected erythrocytes, causing blood cells to stick to each other and to the walls of blood vessels. process impedes blood flow, sometimes leading to organ failure, anemia, jaundice and even death

systemic infection

a type of infection that becomes disseminated throughout the body Usually because it's a pathogen in the blood

secondary infection

a type of infection that was led to by a primary infection

primary infection

a type of infection that's initial and caused by one pathogen

focal infection

a type of infection where a localized pathogen, or the toxins it produces, can spread to a secondary location.

Secretions and excretions

actions that can transport pathogens

Proteases 2

aid in immune system evasion Pathogens produce these to protect against phagocytosis combat antibody-mediated killing and clearance by attacking and digesting the antibody molecules

kinases

aid in immune system evasion trigger the conversion of plasminogen to plasmin, which is involved in the digestion of fibrin clots By digesting a clot, kinases allow pathogens trapped in the clot to escape and spread, similar to the way that collagenase, hyaluronidase, and DNAse facilitate the spread of infection

antigenic variation

aids in immune system evasion A final mechanism pathogens can use to protect themselves against the immune system alteration of surface proteins so that a pathogen is no longer recognized by the host's immune system

mycolic acid

aids in immune system evasion enables the bacterium to resist some of the killing mechanisms within the phagolysosome

Coagulase

aids in immune system evasion by exploiting the natural mechanism of blood clotting to evade the immune system provides an important protective barrier from the immune system, but when nutrient supplies are diminished or other conditions signal a need for the pathogen to escape and spread, the production of staphylokinase can initiate this process. If bacteria release coagulase into the bloodstream, the fibrinogen-to-fibrin cascade is triggered in the absence of blood vessel damage. resulting clot coats the bacteria in fibrin, protecting the bacteria from exposure to phagocytic immune cells circulating in the bloodstream.

Hyaluronidase

an exoenzyme produced by pathogens like Staphylococcus aureus, Streptococcus pyogenes, and Clostridium perfringens degrades the glycoside hyaluronan (hyaluronic acid), which acts as an intercellular cement between adjacent cells in connective tissue

cholera enterotoxin (targets digestive system)

an exotoxin produced by the gram-negative bacterium Vibrio cholerae and is composed of one A subunit and five B subunits. B subunits bind to receptors on the intestinal epithelial cell of the small intestine. also an enterotoxin which is a toxin produced in or affecting the intestines, such as those causing food poisoning or cholera. After gaining entry into the cytoplasm of the epithelial cell, the A subunit activates an intracellular G protein. activated G protein, in turn, leads to the activation of the enzyme adenyl cyclase, which begins to produce an increase in the concentration of cyclic AMP (a secondary messenger molecule). increased cAMP disrupts the normal physiology of the intestinal epithelial cells and causes them to secrete excessive amounts of fluid and electrolytes into the lumen of the intestinal tract, resulting in severe "rice-water stool" diarrhea characteristic of cholera.

diphtheria exotoxin

an exotoxin that's a causative agent of nasopharyngeal and cutaneous diphtheria After a subunit of this separates and gains access to the cytoplasm, it facilitates the transfer of adenosine diphosphate (ADP)-ribose onto an elongation-factor protein (EF-2) that is needed for protein synthesis. this inhibits protein synthesis in the host cell, killing the cell

botulinum neurotoxin

an exotoxin that's the most acutely toxic substance Composed of light A subunit and heavy protein chain B subunit B binds to neurons to allow toxin to enter neuron at neuromuscular junction Subunit A acts as protease, splitting proteins involved in the neuron's release of acetylcholine Ability to block acetylcholine release leads to inhibition of muscle contractions aka leading to muscles relaxing Has potential to stop breathing and cause death Used for botox Flaccid- floppy

Aspergillus

an opportunistic fungal pathogen and virulence factor that can enter the body via contaminated food or by inhalation. mycotoxin aflatoxin is a virulence factor produced Inhalation can lead to the chronic pulmonary disease aspergillosis, characterized by fever, bloody sputum, and/or asthma. Aflatoxin acts in the host as both a mutagen (a substance that causes mutations in DNA) and a carcinogen (a substance involved in causing cancer), and has been associated with the development of liver cancer Gliotoxin promotes virulence by inducing host cells to self-destruct and by evading the host's immune response by inhibiting the function of phagocytic cells as well as the pro-inflammatory response produces several proteases- elastase breaks down protein elastin found in connective tissue of the lung, leading to development of lung disease; catalase, an enzyme that protects the fungus from hydrogen peroxide produced by the immune system to destroy pathogens.

Candida albicans

an opportunistic fungal pathogen, virulence factor, and causative agent of oral thrush, vaginal yeast infections, and cutaneous candidiasis produces adhesins (surface glycoproteins) that bind to the phospholipids of epithelial and endothelial cells produces proteases and phospholipases to aid in spread and tissue invasion phospholipases can affect the integrity of host cell membranes to facilitate invasion.

disease

any condition in which the normal structure or functions of the body are damaged or impaired.

communicable disease

any disease capable of being spread from person to person through either direct (person to person) or indirect (person to fomite to person) mechanisms

infectious disease

any disease caused by the direct effect of a pathogen

contagious disease

any disease easily spread from person to person

noncommunicable disease

any disease that does not spread from one person to another

opportunistic pathogen

can only cause disease in situations that compromise the host's defenses, such as the body's protective barriers, immune system, or normal microbiota.

Primary pathogen

cause disease in a host regardless of the host's resident microbiota or immune system

adhesions

contribute to influenza viral virulence The interaction of viral adhesins with specific cell receptors defines the tropism (preferential targeting) of viruses for specific cells, tissues, and organs in the body. Hemagglutinin allows the virus to bind to the sialic acid on the membrane of host respiratory and intestinal cells

antigenic shift

contribute to influenza viral virulence major change in spike proteins due to gene reassortment reassortment for antigenic shift occurs when two different influenza viruses infect the same host

antigenic drift

contribute to influenza viral virulence result of point mutations causing slight changes in the spike proteins hemagglutinin (H) and neuraminidase (N)

Helminths

depend heavily on virulence factors that allow them to gain entry to host tissues Schistosoma mansoni- causes schistosomiasis, penetrates intact skin with the aid of proteases that degrade skin proteins, including elastin Some are large enough where immune system is ineffective against them Glycan polysaccharides on external surface resembles host molecules, tricking immune system "glycan gimmickry" can actively suppress the immune system produce many other substances that suppress elements of both innate nonspecific and adaptive specific host defenses

portal specificity

determined by the organism's environmental adaptions and by the enzymes and toxins they secrete

nosocomial disease

diseases acquired in hospital settings. Pathogens brought from sick patients can be transferred via improperly sterilized medical equipment, bed sheets, call buttons, door handles or clinicians or nurses that have not washed their hands before touching a patient.

Superantigens

exotoxins that trigger an excessive, nonspecific stimulation of immune cells to secrete cytokines (chemical messengers). excessive production of cytokines, often called a cytokine storm, elicits a strong immune and inflammatory response that can cause life-threatening high fevers, low blood pressure, multi-organ failure, shock, and death. Often released by Staphylococcus aureus and Streptococcus pyogenes

infection 2

fourth and final stage of the 4 stages of pathogenesis after invasion Following invasion, successful multiplication of the pathogen leads to this Local, focal, or systematic

signs

objective and measurable, and can be directly observed by a clinician i.e. a rash

protozoa

have unique features for attaching to host cells

acute disease

illness period for this type of disease: Hours, days, or a few weeks

chronic diseases

illness period for this type of disease: Months, years, or a lifetime

latent diseases

illness period for this type of disease: Pathogen can be dormant for extended periods of time without replication

ID50

number of pathogen cells or virions required to cause active infection in 50% of inoculated animals.

LD50

number of pathogenic cells, virions, or amount of toxin required to kill 50% of infected animals When this is lower this means higher virulence (inversely proportional) A- this is 100, B-this is 100,000. A has more virulence

septicemia

patients with this infection are described as septic, which can lead to shock, a life-threatening decrease in blood pressure (systolic pressure <90 mm Hg) that prevents cells and organs from receiving enough oxygen and nutrients. Some bacteria can cause shock through the release of toxins (virulence factors that can cause tissue damage) and lead to low blood pressure. Gram-negative bacteria are engulfed by immune system phagocytes, which then release tumor necrosis factor, a molecule involved in inflammation and fever.

coughing and sneezing

secretions that can expel pathogens from the respiratory tract

adhesion

second stage of the 4 stages of pathogenesis, following exposure and before invasion capability of pathogenic microbes to attach to the cells of the body using adhesion factors, and different pathogens use various mechanisms to adhere to the cells of host tissues. Adhesins (molecules that are proteins or carbs) are found on the surface of certain pathogens and bind to specific receptors on host cells Adhesins are present on fimbriae and flagella of bacteria, cilia of protozoa, and capsid or membrane of virus Biofilm growth can be an adhesion factor Production of glycocalyces allow some bacterial pathogens to attach to cells

symptoms

subjective and are felt or experienced by the patient, but they cannot be clinically confirmed or objectively measured i.e. nausea

infection

successful colonization of a host by a microorganism.

pathogenicity

the ability of a microbial agent to cause disease

virulence

the degree to which an organism is pathogenic

Convalescence period

the fifth and last period of disease Patient returns to normal functions Some disease cause permanent damage

incubation period

the first out of the 5 periods of disease occurs in an acute disease after the initial entry of the pathogen into the host (patient) pathogen begins multiplying in the host. there are insufficient numbers of pathogen particles (cells or viruses) present to cause signs and symptoms of disease Period can vary from 1-2 days for acute disease or months to years in chronic disease (depends on pathogen) Patient is unaware a disease is developing

decline period

the fourth out of the 5 periods of disease Number of pathogen particles decrease Signs and symptoms decrease Patients may be more susceptible to developing secondary infections due to weakened immune systems from primary infection (such as from an opportunistic pathogen)

Prodromal period

the second out of the 5 periods of disease "Oh no I think I'm getting sick!" After incubation Pathogen continues to multiply Host begins feeling signs and symptoms of illness (typically result from activation of the immune system- fever, pain, swelling, etc.) Signs are too general to indicate specific disease

Illness period

the third out of the 5 periods of disease Signs and symptoms are most obvious and severe

asymptomatic or subclinical

they do not present any noticeable signs or symptoms

invasion

third stage of the 4 stages of pathogenesis after adhesion and before infection involves the spreading of a pathogen throughout local tissues or the body Pathogens may produce exoenzymes or toxins, which serve as virulence factors that allow them to colonize and damage host tissues as they spread deeper into the body Pathogens may also produce virulence factors that protect them against immune system defenses. A pathogen's specific virulence factors determine the degree of tissue damage that occurs. Intracellular pathogens achieve invasion by entering the host's cells and reproducing. Some are obligate intracellular pathogens (meaning they can only reproduce inside of host cells) and others are facultative intracellular pathogens (meaning they can reproduce either inside or outside of host cells).