Q: Which equation correctly represents the calculation of the infection fatality ratio (IFR)?

$$\text{IFR} = \frac{\text{Number of deaths}}{\text{Total number of infected individuals}}$$

Q: Which equation represents the calculation of prevalence?

$$\text{Prevalence} = \frac{\text{Number of people who have a disease at a specified time}}{\text{Total population}}$$

Question 1

Which of the following best describes the difference between normal microbiota and transient microbiota?

Accepted Answer

Normal microbiota permanently colonize the host and do not cause disease under normal conditions, while transient microbiota are present for a limited time and may disappear.

Question 2

A patient develops a severe intestinal infection after antibiotic treatment. Which microorganism is most likely responsible, and what is a recommended treatment?

Accepted Answer

Clostridium difficile; treat with fecal microbial transfer (FMT).

Question 3

Which of the following is NOT one of Koch’s postulates?

Accepted Answer

The pathogen must be able to infect any species, including plants.

Question 4

Which equation correctly represents the calculation of the infection fatality ratio (IFR)?

Accepted Answer

$$	ext{IFR} = \frac{	ext{Number of deaths}}{	ext{Total number of infected individuals}}$$

Question 5

Which of the following is an example of mutualism in the human microbiome?

Accepted Answer

E. coli in the large intestine

Question 6

A disease that is constantly present in a population is best described as:

Accepted Answer

Endemic

Question 7

Which of the following is a predisposing factor for disease?

Accepted Answer

Vaccination

Question 8

During which stage of disease is the number of microbes at its highest and symptoms most severe?

Accepted Answer

Period of illness

Question 9

Which of the following is an example of vehicle transmission?

Accepted Answer

Eating undercooked chicken contaminated with Salmonella

Question 10

Which equation represents the calculation of prevalence?

Accepted Answer

$$	ext{Prevalence} = \frac{	ext{Number of people who have a disease at a specified time}}{	ext{Total population}}$$

Question 11

Which of the following best describes herd immunity?

Accepted Answer

Immunity in most of a population, reducing the spread of disease.

Question 12

Which of the following is a zoonosis transmitted by direct contact with animals?

Accepted Answer

Rabies

Question 13

A hospital patient develops a urinary tract infection after catheterization. This is an example of:

Accepted Answer

A healthcare-associated infection (HAI)

Question 14

Which of the following is NOT a method to prevent healthcare-associated infections?

Accepted Answer

Increasing the use of invasive procedures

Question 15

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

Accepted Answer

A tick transmitting Lyme disease after the pathogen reproduces inside the tick

Question 16

Which equation correctly represents the calculation of mortality rate?

Accepted Answer

$$	ext{Mortality rate} = \frac{	ext{Number of deaths from a disease}}{	ext{Total population}}$$

Question 17

Which of the following is a reason for the emergence of new infectious diseases?

Accepted Answer

Genetic recombination between organisms

Question 18

Which type of epidemiology involves collection and analysis of data to identify the source of an outbreak?

Accepted Answer

Descriptive epidemiology

Question 19

A patient is infected with a virus but shows no noticeable signs or symptoms. This is best described as:

Accepted Answer

Subclinical infection

Question 20

Which of the following is a function of the Centers for Disease Control and Prevention (CDC)?

Accepted Answer

Collects and analyzes epidemiological information in the United States

Principles of Disease and Epidemiology: Microbiology Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards