$$\text{CFR} = \frac{\text{Number of deaths due to disease}}{\text{Number of persons infected}} \times 100$$

$$\text{Prevalence} = \frac{\text{Total number of cases in population}}{\text{Total number of persons in population}} \times 100$$

$$\text{Incidence} = \frac{\text{Number of new cases in a designated time period}}{\text{Total number of susceptible persons}}$$

Question 1

Which of the following best describes an opportunistic pathogen?

Accepted Answer

A pathogen that only causes disease when the host is weakened.

Question 2

Which equation correctly calculates the case fatality rate (CFR)?

Accepted Answer

$$	ext{CFR} = \frac{	ext{Number of deaths due to disease}}{	ext{Number of persons infected}} 	imes 100$$

Question 3

A patient contracts Salmonella from contaminated food. What mode of transmission is this?

Accepted Answer

Vehicle transmission

Question 4

Which phase of infectious disease progression is characterized by the highest pathogen levels and full-blown symptoms?

Accepted Answer

Acute phase

Question 5

Which of the following is NOT a limitation of Koch’s postulates?

Accepted Answer

They can always be used to identify viral pathogens.

Question 6

Which equation is used to calculate disease prevalence?

Accepted Answer

$$	ext{Prevalence} = \frac{	ext{Total number of cases in population}}{	ext{Total number of persons in population}} 	imes 100$$

Question 7

Which of the following is a biological vector for disease transmission?

Accepted Answer

Mosquito transmitting malaria

Question 8

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

Accepted Answer

Healthcare-associated infection (HAI)

Question 9

Which factor is NOT part of the epidemiological triangle?

Accepted Answer

Vaccination status

Question 10

Which of the following is a reason why listeriosis is difficult to track epidemiologically?

Accepted Answer

Most cases are asymptomatic and go undetected.

Question 11

Which public health strategy is most effective for preventing healthcare-associated infections (HAIs)?

Accepted Answer

Consistent hand washing by healthcare workers

Question 12

Which equation is used to calculate disease incidence?

Accepted Answer

$$	ext{Incidence} = \frac{	ext{Number of new cases in a designated time period}}{	ext{Total number of susceptible persons}}$$

Question 13

Which of the following is a communicable disease?

Accepted Answer

Measles

Question 14

Which of the following is a key ethical principle in modern epidemiological research?

Accepted Answer

Informed consent

Question 15

Which of the following is a real-world example of a reemerging disease?

Accepted Answer

Antibiotic-resistant bacteria

Question 16

Which of the following is a primary goal of epidemiology?

Accepted Answer

Describing the nature, cause, and extent of diseases in populations

Question 17

A disease is considered eradicated when:

Accepted Answer

There are no longer any cases anywhere in the world.

Question 18

Which of the following is a common misconception about herd immunity?

Accepted Answer

Herd immunity can be achieved with low vaccination rates.

Question 19

Which of the following is an example of a mechanical vector?

Accepted Answer

Fly landing on dog feces and then on a picnic lunch

Question 20

Which of the following is a reason why surveillance of reportable diseases is important?

Accepted Answer

It enables earlier detection of outbreaks.

Principles of Infectious Disease and Epidemiology: Microbiology Study Guide

Study Guide - Practice Questions