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

Question 1

Which of the following best describes a mutualistic relationship between microbes and their hosts?

Accepted Answer

Both organisms benefit from the relationship.

Question 2

A patient develops a yeast infection after taking broad-spectrum antibiotics for a bacterial infection. This is an example of which type of pathogen?

Accepted Answer

Opportunistic pathogen

Question 3

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

Accepted Answer

Liver

Question 4

A researcher is investigating a new disease outbreak. According to Koch’s postulates, which step must be completed to prove causation?

Accepted Answer

The cultured agent must cause the disease when introduced into a healthy host.

Question 5

Which of the following is a correct equation for calculating disease prevalence?

Accepted Answer

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

Question 6

Which of the following is an example of vehicle transmission?

Accepted Answer

A person develops cholera after drinking contaminated water.

Question 7

Which virulence factor allows bacteria to evade phagocytosis by host immune cells?

Accepted Answer

Bacterial capsule

Question 8

A patient is infected with a pathogen that produces cytotoxins, leading to cell death. This is an example of which type of virulence factor?

Accepted Answer

Exotoxin

Question 9

Which of the following best describes an endemic disease?

Accepted Answer

A disease that occurs at a stable frequency within a given population or area.

Question 10

Which of the following is the most effective way to reduce healthcare-associated (nosocomial) infections?

Accepted Answer

Handwashing by healthcare workers

Question 11

A disease that develops rapidly and runs its course quickly is classified as:

Accepted Answer

Acute

Question 12

Which of the following is a sign, not a symptom, of disease?

Accepted Answer

Fever

Question 13

Which of the following is a correct description of a zoonosis?

Accepted Answer

A disease that is transmitted from animals to humans.

Question 14

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

Accepted Answer

A person contracts a cold after touching a contaminated doorknob.

Question 15

Which of the following best explains why some pathogens cannot be studied using Koch’s postulates?

Accepted Answer

Some pathogens cannot be grown in pure culture.

Question 16

A patient is infected with a bacterium that produces leukocidins. What is the primary effect of this virulence factor?

Accepted Answer

It destroys phagocytic white blood cells.

Question 17

Which of the following is a function of public health agencies in controlling infectious diseases?

Accepted Answer

Enforcing cleanliness of water and food supplies

Question 18

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

Accepted Answer

The period with vague, general symptoms.

Question 19

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

Accepted Answer

A mosquito transmitting malaria

Question 20

Which of the following equations correctly represents the calculation for incidence?

Accepted Answer

$$	ext{Incidence} = \frac{	ext{Number of new cases}}{	ext{Population at risk}}$$

Infection, Infectious Diseases, and Epidemiology – Study Notes

Study Guide - Practice Questions