chp 15 microbiology

a. Less virulent pathogens may cause an initial infection but may not always cause severe illness. Pathogens with low ___________ would more likely result in mild signs and symptoms of disease, such as low-grade fever, headache, or muscle aches. Some individuals might even be asymptomatic.

virulence

step 2: _________(colonization) refers to the capability of pathogenic microbes to attach to the cells of the body using ___________ factors, and different pathogens use various mechanisms to adhere to the cells of host tissues.

1. Adhesion

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

1. Koch's Postulates

To cause disease, a pathogen must successfully achieve four steps:

1. exposure 2.adhesion 3. invasion 4. infection

what is the order of period of diseases?

1.incubation, 2. prodromal, 3.period of illness, 4.period of decline, 5.final period-period of convalescence

what is a normal breathing rate

12-18 breaths per minute

what is normal heart rate

60-100 bpm

what is a normal body temp

96.6 or 37 celcius

1. An example of a highly virulent microorganism is ________ ___________, the pathogen responsible for anthrax. B. anthracis can produce different forms of disease, depending on the route of transmission (e.g., cutaneous injection, inhalation, ingestion). The most serious form of anthrax is _________ anthrax. After B. anthracis spores are inhaled, they ___________. An active infection develops, and the bacteria release potent toxins that cause _____(fluid buildup in tissues), ______(a condition preventing oxygen from reaching tissues), and ______(cell death and inflammation). Signs and symptoms of inhalation _________ include high fever, difficulty breathing, vomiting and coughing up blood, and severe chest pains suggestive of a heart attack. With inhalation anthrax, the toxins and bacteria enter the bloodstream, which can lead to multi-organ failure and death of the patient. If a gene (or genes) involved in pathogenesis is inactivated, the bacteria become less virulent or nonpathogenic.

Bacillus anthracis; inhalation; germinate; edema; hypoxia; necrosis; anthrax

what is an example of chronic disease?

Ex: chronic gastritis (inflammation of the lining of the stomach) is caused by the gram-negative bacterium Helicobacter pylori. H. pylori is able to colonize the stomach and persist in its highly acidic environment by producing the enzyme urease, which modifies the local acidity, allowing the bacteria to survive indefinitely

step 1: _______ (contact) An encounter with a potential pathogen is known as exposure or contact.

Exposure

a. __________ is not as contagious as measles because transmission of the pathogen (Neisseriagonorrhoeae) requires close intimate contact (usually sexual) between an infected person and an uninfected person.

Gonorrhea

a. __________ diseases can occur after procedures involving wound treatments, catheterization, or surgery if the wound or surgical site becomes contaminated.

Iatrogenic

a. ________ is a highly contagious viral disease that can be transmitted when an infected person coughs or sneezes and an uninfected person breathes in droplets containing the virus.

Measles

infectious diseases not transmitted between humans directly but can be transmitted from animals to humans. According to WHO, a ____________ is a disease that occurs when a pathogen is transferred from a vertebrate animal to a human; however, sometimes the term is defined more broadly to include diseases transmitted by all animals (including invertebrates).

Zoonotic diseases (or zoonosis)

what Is an example of iatrogenic disease?

a. Ex: an individual treated for a skin wound might acquire necrotizing fasciitis (an aggressive, "flesh-eating" disease) if bandages or other dressings became contaminated by Clostridium perfringens or one of several other bacteria that can cause this condition.

what is an example of acute disease?

a. Ex: influenza (caused by Influenzavirus) is considered an acute disease because the incubation period is approximately 1-2 days a. Infected individuals can spread influenza to others for approximately 5 days after becoming ill. b. After approximately 1 week, individuals enter the period of decline..

a. Ex: ______ is indicative of many types of infection, from the common cold to the deadly Ebola hemorrhagic fever.

fever

a. Many other zoonotic diseases rely on insects or other arthropods for __________. Examples include yellow fever (transmitted through the bite of mosquitoes infected with yellow fever virus) and Rocky Mountain spotted fever (transmitted through the bite of ticks infected with Rickettsia rickettsii).

transmission

what are factors that contribute to the prevalence and severity of nosocomial diseases?

a. First, sick patients bring numerous pathogens into hospitals, and some of these pathogens can be transmitted easily via improperly sterilized medical equipment, bed sheets, call buttons, door handles, or by clinicians, nurses, or therapists who do not wash their hands before touching a patient. b. Second, many hospital patients have weakened immune systems, making them more susceptible to infections. c. Compounding this, the prevalence of antibiotics in hospital settings can select for drug-resistant bacteria that can cause very serious infections that are difficult to treat.

what are some symptoms?

a. Nausea b. loss of appetite c. pain d. Such symptoms are important to consider when diagnosing disease, but they are subject to memory bias and are difficult to measure precisely. e. Some clinicians attempt to quantify symptoms by asking patients to assign a numerical value to their symptoms. For example, the Wong-Baker Faces pain-rating scale asks patients to rate their pain on a scale of 0-10.

1. . Noninfectious diseases can be caused by a wide variety factors:

a. genetics. Ex: sickle cell anemia is an inherited disease caused by a genetic mutation that can be passed from parent to offspring b. the environment c. immune system dysfunction.

what are two examples of latent diseases?

a. herpes (herpes simplex viruses [HSV-1 and HSV-2]) b. chickenpox (varicella-zoster virus [VZV]) an initial infection by VZV may result in a case of childhood chickenpox, followed by a long period of latency. The virus may reactivate decades later, causing episodes of shingles in adulthood.

1. For an ______ disease, pathologic changes occur over a relatively short time (e.g., hours, days, or a few weeks) and involve a rapid onset of disease conditions.

acute

Molecules (either proteins or carbohydrates) called __________ are found on the surface of certain pathogens and bind to specific receptors (glycoproteins) on host cells. ___________ are present on the fimbriae and flagella of bacteria, the cilia of protozoa, and the capsids or membranes of viruses. Protozoans can also use hooks and barbs for adhesion; spike proteins on viruses also enhance viral adhesion.

adhesins

a. On one end of the spectrum are organisms that are ____________ (not harmful) and on the other are organisms that are highly _________. Highly _______pathogens will almost always lead to a disease state when introduced to the body, and some may even cause multi-organ and body system failure in healthy individuals.

avirulent; virulent

________growth can also act as an adhesion factor. A __________is a community of bacteria that produce a glycocalyx, known as ___________ substance (EPS), that allows the biofilm to attach to a surface. Persistent _________ ___________ infections are common in patients suffering from cystic fibrosis, burn wounds, and middle-ear infections (otitis media) because P. aeruginosa produces a biofilm. The ____ allows the bacteria to adhere to the host cells and makes it harder for the host to physically remove the pathogen

biofilm; extrapolymeric;Pseudomonas aeruginosa; EPS

1. For a ______ disease, pathologic changes can occur over longer time spans (e.g., months, years, or a lifetime).

chronic

Some infectious diseases are also __________, meaning they are capable of being spread from person to person through either direct or indirect mechanisms.

communicable

1. Some infectious communicable diseases are also considered ________ diseases, meaning they are easily spread from person to person. Not all ________diseases are equally so; the degree to which a disease is contagious usually depends on how the pathogen is transmitted.

contagious

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

disease

i. Changes in any of the body's vital signs may be indicative of ______. For example, having a fever (a body temperature significantly higher than 37 °C or 98.6 °F) is a sign of disease because it can be measured.

disease

_____ _______a localized pathogen, or the toxins it produces, can spread to a secondary location. For example, a dental hygienist nicking the gum with a sharp tool can lead to a local infection in the gum by ___________ bacteria of the normal oral microbiota. These Streptococcus spp. may then gain access to the bloodstream and make their way to other locations in the body, resulting in a secondary infection.

focal infection; Streptococcus

Diseases that are contracted as the result of a medical procedure are known

iatrogenic diseases

is the successful colonization of a host by a microorganism. _________can lead to disease, which causes signs and symptoms resulting in a deviation from the normal structure or functioning of the host.

infection

step 4: ______ can be described as local, focal, or systemic, depending on the extent of the infection.

infection

An _______ disease is any disease caused by the direct effect of a pathogen

infectious

step 3: ______ involves the dissemination of a pathogen throughout local tissues or the body.

invasion

1. In _______diseases, as opposed to chronic infections, the causal pathogen goes dormant aka latent for extended periods of time with no active replication. HSV-1, HSV-2, and VZV evade the host immune system by residing in a latent form within cells of the nervous system for long periods of time, but they can reactivate to become active infections during times of stress and immunosuppression.

latent

is confined to a small area of the body, typically near the portal of entry. For example, a hair follicle infected by Staphylococcus aureus infection may result in a boil around the site of infection, but the bacterium is largely contained to this small location.

local infection

1. In contrast to communicable infectious diseases, a _________ infectious disease is not spread from one person to another. One example is __________, caused by Clostridium tetani, a bacterium that produces endospores that can survive in the soil for many years. This disease is typically only transmitted through contact with a skin wound; it cannot be passed from an infected person to another person. Similarly, _________ disease is caused by Legionella pneumophila, a bacterium that lives within amoebae in moist locations like water-cooling towers. An individual may contract___________ disease via contact with the contaminated water, but once infected, the individual cannot pass the pathogen to other individuals.

noncommunicable; tetanus; Legionnaires; Legionnaires

__________ diseases (those not caused by pathogens) are an important cause of morbidity and mortality worldwide.

noninfectious

what is a normal BP

normally between 90/60 mm Hg - 120/80 mm Hg).

1. Diseases acquired in hospital settings are known as ________diseases. Several factors contribute to the prevalence and severity of nosocomial diseases.

nosocomial

1. An __________ pathogen, by contrast, can only cause disease in situations that compromise the host's defenses, such as the body's protective barriers, immune system, or normal microbiota. Individuals susceptible to opportunistic infections include the very young, the elderly, women who are pregnant, patients undergoing chemotherapy, people with immunodeficiencies (such as acquired immunodeficiency syndrome [AIDS]), patients who are recovering from surgery, and those who have had a breach of protective barriers (such as a severe wound or burn).

opportunistic

A _______ may be cellular (bacteria, parasites, and fungi) or acellular (viruses, viroids, and prions)

pathogen

The duration of the period of illness can vary greatly, depending on the ________,

pathogen

1. The ability of a microbial agent to cause disease is called ___________, and the degree to which an organism is pathogenic is called __________. _________is a continuum.

pathogenicity; virulence.

Microorganisms that can cause disease are known as

pathogens

In pregnant women, the ________ normally prevents microorganisms from passing from the mother to the fetus. However, a few _________ are capable of crossing the blood-placental barrier. The gram-positive bacterium ___________________, which causes the foodborne disease listeriosis, is one example that poses a serious risk to the fetus and can sometimes lead to spontaneous abortion.

placenta; pathogens; Listeriamonocytogenes

a. An anatomic site through which pathogens can pass into host tissue is called a _____ of _______. These are locations where the host cells are in direct contact with the external environment. Major portals of entry are identified in and include the skin, mucous membranes, and parenteral routes.

portal of entry

For a pathogen to persist, it must put itself in a position to be transmitted to a new host, leaving the infected host through a _______ of _______. As with portals of entry, many pathogens are adapted to use a particular portal of exit. Similar to portals of entry, the most common portals of ______ include the skin and the respiratory, urogenital, and gastrointestinal tracts. Coughing and sneezing can expel pathogens from the respiratory tract. A single sneeze can send thousands of virus particles into the air. ________ and ________ can transport pathogens out of other portals of exit. Feces, urine, semen, vaginal secretions, tears, sweat, and shed skin cells can all serve as vehicles for a pathogen to leave the body. Pathogens that rely on insect vectors for transmission exit the body in the blood extracted by a biting insect. Similarly, some pathogens exit the body in blood extracted by needles.

portal of exit; Secretions and excretions

1. A _________ pathogen can cause disease in a host regardless of the host's resident microbiota or immune system.

primary

a. a ________ infection, the initial infection caused by one pathogen, can lead to a __________ infection by another pathogen. For example, the immune system of a patient with a primary infection by ______ becomes compromised, making the patient more susceptible to secondary diseases like oral thrush and others caused by opportunistic pathogens. Similarly, a primary infection by ________ virus damages and decreases the defense mechanisms of the lungs, making patients more susceptible to a secondary pneumonia by a bacterial pathogen like Haemophilus influenzae or Streptococcus pneumoniae. Some secondary infections can even develop as a result of treatment for a primary infection. _________ therapy targeting the primary pathogen can cause collateral damage to the normal microbiota, creating an opening for opportunistic pathogens

primary; secondary; HIV; Influenza; Antibiotic

a. For example, ____ is a viral zoonotic disease spread from animals to humans through bites and contact with infected saliva.

rabies

1. The ______ of disease are objective, measurable, and can be directly observed by a clinician.

signs

occurs in an acute disease after the initial entry of the pathogen into the host (patient). However, there are insufficient numbers of pathogen particles (cells or viruses) present to cause signs and symptoms of disease. ___________periods can vary from a day or two in acute disease to months or years in chronic disease, depending upon the pathogen.

step 1: incubation

1. The __________ period occurs after the incubation period. During this phase, the pathogen continues to multiply, and the host begins to experience general signs and symptoms of illness, which typically result from activation of the immune system, such as fever, pain, soreness, swelling, or inflammation. Usually, such signs and symptoms are too general to indicate a particular disease.

step 2: prodromal period

1. The period of _______, during which the signs and symptoms of disease are most obvious and severe.

step 3: period of illness

1. The period of ________during which the number of pathogen particles begins to decrease, and the signs and symptoms of illness begin to decline. However, during the decline period, patients may become susceptible to developing secondary infections because their immune systems have been weakened by the primary infection.

step 4: period of decline

1. The final period is known as the period of __________. During this stage, the patient generally returns to normal functions, although some diseases may inflict permanent damage that the body cannot fully repair.

step 5: final step-convalescence

Unlike signs, _______of disease are subjective. ________are felt or experienced by the patient, but they cannot be clinically confirmed or objectively measured.

symptoms

1. A specific group of signs and symptoms characteristic of a particular disease is called a _________. Many ________ are named using a nomenclature based on signs and symptoms or the location of the disease.

syndromes

an infection becomes disseminated throughout the body. For example, infection by the varicella-zoster virus typically gains entry through a mucous membrane of the upper respiratory system. It then spreads throughout the body, resulting in the classic red skin lesions associated with chickenpox. Since these lesions are not sites of initial infection, they are signs of a systemic infection.

systemic infection

a. Pathogens may produce exoenzymes or ________, which serve as virulence factors that allow them to colonize and damage host tissues as they spread deeper into the body. ________ 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. Ex: _____ ______

toxins; Pathogens; H. pylori.