Question 1

Which of the following best describes the difference between incidence and prevalence of a disease in a population?

Accepted Answer

Incidence refers to the number of new cases over a period, while prevalence refers to the total number of cases at a given time.

Question 2

A hospital patient develops a urinary tract infection after catheterization. This infection is best classified as:

Accepted Answer

An iatrogenic nosocomial infection

Question 3

Which of the following is a key step in Koch’s postulates for proving the causative agent of a disease?

Accepted Answer

The suspected agent must be isolated and grown in pure culture.

Question 4

Which of the following is NOT a typical portal of entry for pathogens?

Accepted Answer

Brain

Question 5

A disease that occurs at a relatively stable frequency within a given area or population is best described as:

Accepted Answer

Endemic

Question 6

Which of the following is a characteristic of endotoxins?

Accepted Answer

They are part of the outer membrane of Gram-negative bacteria.

Question 7

A patient presents with fever, vomiting, and a swollen lymph node. Which of these is a symptom rather than a sign?

Accepted Answer

Feeling nauseous

Question 8

Which of the following best explains why influenza epidemics can occur even in populations with prior exposure to the virus?

Accepted Answer

Antigenic drift leads to small changes in viral antigens, allowing the virus to evade immune detection.

Question 9

Which of the following is an example of a biological vector in disease transmission?

Accepted Answer

A mosquito transmitting malaria through its bite

Question 10

Which of the following is a function of bacterial capsules in immune evasion?

Accepted Answer

They prevent phagocytosis by masking bacterial antigens.

Question 11

A patient is infected with a pathogen that produces hyaluronidase and collagenase. What is the most likely effect of these enzymes?

Accepted Answer

They facilitate tissue invasion by breaking down host connective tissue.

Question 12

Which of the following is a zoonotic disease and its correct animal reservoir?

Accepted Answer

Rabies – bats

Question 13

Which of the following body fluids is normally microbe-free in a healthy individual?

Accepted Answer

Blood

Question 14

Which of the following best describes the prodromal period of an infectious disease?

Accepted Answer

The period with vague, general symptoms before the illness phase.

Question 15

Which of the following is a correct statement about the control of nosocomial infections?

Accepted Answer

They are best controlled by a combination of hand hygiene, isolation procedures, and antibiotic stewardship.

Question 16

Which of the following is an example of indirect contact transmission?

Accepted Answer

A person touches a contaminated doorknob and then touches their mouth.

Question 17

Which of the following is a plausible reason why the prevalence of HIV/AIDS in the U.S. increased steadily from 1980 to 2010, even though the incidence remained relatively stable?

Accepted Answer

People with HIV/AIDS lived longer due to improved treatments, increasing the total number of cases.

Question 18

Which of the following is a correct example of antigenic variation as a virulence factor?

Accepted Answer

Neisseria gonorrhoeae altering its surface proteins to evade immune detection.

Question 19

Which of the following is a correct statement about exotoxins?

Accepted Answer

They are secreted proteins that can be converted to toxoids for vaccines.

Question 20

A patient develops a fever and shock after receiving antibiotics for a Gram-negative bacterial infection. What is the most likely cause?

Accepted Answer

Release of endotoxin (lipid A) from dead bacteria

Epidemiology and Host-Microbe Relationships: Study Guide

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