Microbiology - Chapter 14

explain how the relationship between a host and its parasite can eventually evolve into mutualism or commensalism

-As you've heard, parasites evolve reduced virulence and hosts evolve increased tolerance; eventually, this may result in the host not being harmed at all. -Or the host may receive some coincidental benefit, which outweighs its loss of nutrients.

an epidemic affecting more than one continent at the same time is called a. a pandemic b. superinfection c. an iatrogenic infection d. an endemic

a. a pandemic

which of the following statements about zoonoses is false? a. humans do not acquire zoonoses by consuming animals b. vaccinating domestic animals prevents zoonoses from spreading c. more than 200 zoonoses have been identified d. Ebola hemorrhagic fever disease is caused by zoonoses

a. humans do not acquire zoonoses by consuming animals

which of the following is the correct sequence of events in infectious diseases? a. incubation, prodromal period, illness, decline, convalescence b. incubation, decline, prodromal period, illness, convalescence c. prodromal period, incubation, illness, decline, convalescence d. convalescence, prodromal period, incubation, illness, decline

a. incubation, prodromal period, illness, decline, convalescence

the most frequent portal of entry for pathogens is a. the respiratory tract b. the skin c. the conjunctiva d. a cut or wound

a. the respiratory tract

a disease in which a pathogen remains inactive for a long period of time before becoming active is termed a(n) a. subacute disease b. acute disease c. chronic disease d. latent disease

d. latent disease

in which type of symbiosis does one symbiont benefit without affecting the other? a. mutualism b. parasitism c. commensalism d. amensalism

c. commensalism

consider the following case. an animal was infected with a virus. a mosquito bit the animal, was contaminated with the virus and proceeded to bite and infect a person. which was the vector? a. animal b. virus c. mosquito d. person

c. mosquito

a microbe's degree of pathogenicity is called

virulence

diseases that are naturally spread from their usual animal hosts to humans are called

zoonoses

the process by which microorganisms attach themselves to cells is a. infection b. contamination c. disease d. adhesion

d. adhesion

the M protein of Streptococcus pyogenes a. has no effect on a body's defense system b. reduces the virulence of the bacteria c. makes human blood clot d. helps the bacteria to inhibit phagocytosis

d. helps the bacteria to inhibit phagocytosis

which of the following are most likely to cause disease a. opportunistic pathogens in a weakened host b. pathogens lacking the enzyme kinase c. pathogens lacking the enzyme collagenase d. highly virulent organisms

d. highly virulent organisms

how does microbial contamination lead to microbial infection

contamination: the mere presence of microbes in or on the body infection: when organism evades body's external defenses, multiplies, and becomes established within the body

nonliving reservoirs of disease, such as a toothbrush, drinking glass, and needle, are called

fomites

endotoxin, also known as ______, is part of the outer (wall) membrane of Gram-negative bacteria

lipid A

the sites through which most pathogens enter the body, called portals of entry, include three major types: the skin, the _____, and the placenta

mucous membranes

_____ infections are those acquired by patients or staff while in health care facilities

nosocomial

the total number of cases of a disease in a given area is its

prevalence

the stages of infectious disease typically consist of the incubation period, ____, illness, decline, and convalescence

prodromal period

define signs, symptoms, and syndromes with regard to microbial infections

signs: objective manifestations of disease observed or measured by others symptoms: subjective characteristics of disease felt only by the patient syndrome: symptoms and signs of disease observed or abnormal condition

contrast iatrogenic and healthcare-associated diseases

- Iatrogenic infections: Are a subset of HAIs that ironically are the direct results of modern medical procedures such as the use of catheters, invasive diagnostic procedures, and surgery. -Healthcare-associated Diseases: Increase the duration and cost of medical care and result in some 100,000 deaths annually in the United States.

contrast the terms infection and morbidity

- Infection- Pathogens overcome the body's external defenses, multiply, and become established in the body. An infection may or may not result in disease. - Morbidity- Is a condition sufficiently adverse to interfere with normal functioning of the body.

list Koch's four postulates, and describe situations in which not all may be applicable

-Suspected agent must be present in every case of disease -Agent must be isolated and grown in pure culture -Cultured agent must cause the disease when it is inoculated into healthy, susceptible experimental host -Same agent must be reisolated from the diseased experimental host Exceptions - some pathogens cannot be cultured -diseases can be caused by a combo of factors -can't infect humans with deadly diseases difficulties - diseases caused by more than one pathogen -organisms ignored as potential sources of disease

in general, contrast transient microbiota with resident microbiota

-The resident microbiota consists of microorganisms that constantly live in or on our bodies. -The term transient microbiota refers to microorganisms that are only temporarily found in the human body, and these may include pathogenic microorganisms

describe how a child acquires the normal microbiota of its body

-may be passed on to offspring via bacteriocytes associated with the ovaries or developing embryo, by feeding larvae with microbe-fortified food, or by smearing eggs with a medium containing microbes during oviposition

list three conditions that create opportunities for pathogens to become harmful in a human

-presence of microorganisms in a hospital setting -immunocompromised patients -Transmission of pathogens between staff and patients and among patients.

describe the parenteral route of infection

defined as that which occurs outside of the alimentary tract, such as in subcutaneous, intravenous, intramuscular, and intrasternal injections