$$\text{Incidence Rate} = \frac{\text{Number of new cases in a defined period}}{\text{Total population at risk during the same period}}$$

$$\text{Prevalence} = \frac{\text{Total number of cases}}{\text{Total population}}$$

Question 1

Which of the following best describes an opportunistic pathogen?

Accepted Answer

A pathogen that only causes disease when the host is weakened, such as by immunosuppression.

Question 2

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

Accepted Answer

They can always be used to identify the cause of latent diseases.

Question 3

A patient develops a fever, rash, and blood in stool. These are examples of:

Accepted Answer

Signs

Question 4

Which of the following best describes the difference between a reservoir and a source in infectious disease transmission?

Accepted Answer

A reservoir is where the pathogen is naturally found; a source is what disseminates the pathogen to new hosts.

Question 5

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

Accepted Answer

A mosquito transmitting malaria to a human.

Question 6

Which stage of infectious disease is characterized by the highest pathogen levels and the most severe symptoms?

Accepted Answer

Acute phase

Question 7

A disease that is routinely detected in a population or region is called:

Accepted Answer

Endemic

Question 8

Which of the following is a correct formula for calculating incidence rate?

Accepted Answer

$$	ext{Incidence Rate} = \frac{	ext{Number of new cases in a defined period}}{	ext{Total population at risk during the same period}}$$

Question 9

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

Accepted Answer

A mosquito transmitting the malaria parasite.

Question 10

Which public health strategy is most effective for controlling diseases with short incubation periods?

Accepted Answer

Quarantine

Question 11

Which of the following best describes herd immunity?

Accepted Answer

When a high percentage of the population is immune, protecting those who are not immune.

Question 12

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

Accepted Answer

Informed consent

Question 13

Which of the following is the best example of a descriptive epidemiological study?

Accepted Answer

A cross-sectional survey measuring the prevalence of HPV infection in cervical cancer patients.

Question 14

Which of the following is a common cause of healthcare-associated infections (HAIs)?

Accepted Answer

Contaminated medical devices

Question 15

Which of the following is a correct formula for calculating prevalence?

Accepted Answer

$$	ext{Prevalence} = \frac{	ext{Total number of cases}}{	ext{Total population}}$$

Question 16

Which of the following is an example of a reemerging infectious disease?

Accepted Answer

Antibiotic-resistant tuberculosis

Question 17

Which of the following is NOT a role of public health agencies?

Accepted Answer

Promoting the spread of infectious diseases

Question 18

Which of the following best describes the epidemiological triangle?

Accepted Answer

It links the host, etiological agent, and environment in the development of disease.

Question 19

Which of the following is a measure of association commonly used in epidemiology?

Accepted Answer

Mortality rate

Question 20

Which of the following is a correct statement about correlation and causation in epidemiology?

Accepted Answer

Correlation does not imply causation.

Principles of Infectious Disease and Epidemiology: Study Guide

Study Guide - Practice Questions