Q: Which formula correctly expresses the incidence rate of a disease in a population?

$$Incidence = \frac{\text{Number of new cases}}{\text{Population at risk} \times \text{Time period}}$$

Question 1

Which of the following best describes the relationship between termites and their gut protozoa and bacteria?

Accepted Answer

Obligate mutualism, because both termites and their gut microbes depend on each other for survival.

Question 2

A patient receives long-term antimicrobial treatment and subsequently develops a Clostridium difficile infection. Which concept best explains this occurrence?

Accepted Answer

Disruption of normal microbiota, allowing opportunistic pathogens to proliferate.

Question 3

Which of the following is NOT a portal of entry for pathogens into the human body?

Accepted Answer

Liver

Question 4

A fungus produces penicillin, which inhibits the growth of nearby bacteria, but the bacteria have no effect on the fungus. What type of symbiotic relationship is this?

Accepted Answer

Amensalism

Question 5

Which of the following best defines 'virulence'?

Accepted Answer

The degree of pathogenicity of a microorganism.

Question 6

A person is infected with a pathogen but does not show symptoms and can still transmit the disease to others. What is this person called?

Accepted Answer

Human carrier

Question 7

Which stage of infectious disease is characterized by the most severe signs and symptoms?

Accepted Answer

Illness

Question 8

Which of the following is an example of vehicle transmission?

Accepted Answer

Transmission through contaminated water.

Question 9

What is the main difference between resident microbiota and transient microbiota?

Accepted Answer

Resident microbiota remain in the body for most of a person's life, while transient microbiota are present for only a short time.

Question 10

Which of the following is a limitation of Koch's postulates?

Accepted Answer

Some pathogens cannot be cultured in the laboratory.

Question 11

Which formula correctly expresses the incidence rate of a disease in a population?

Accepted Answer

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

Question 12

Which of the following is an example of a zoonosis?

Accepted Answer

Rabies transmitted from a dog to a human.

Question 13

A patient develops an infection after a surgical procedure due to bacteria entering through a break in the skin. Which portal of entry is involved?

Accepted Answer

Parenteral route

Question 14

Which of the following is a virulence factor that allows bacteria to evade phagocytosis?

Accepted Answer

Antiphagocytic factors

Question 15

Which of the following best describes an epidemic disease?

Accepted Answer

A sudden increase in cases in a population or region.

Question 16

Which of the following is NOT a method by which humans can acquire zoonoses?

Accepted Answer

Receiving a vaccine

Question 17

Which of the following is a correct statement about the stages of infectious disease?

Accepted Answer

The prodromal period is characterized by mild symptoms.

Question 18

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

Accepted Answer

Touching contaminated money and then touching your mouth.

Question 19

Which of the following is a reason why foodborne transmission is less of a problem today than in the past?

Accepted Answer

Refrigeration and standardized butchering practices reduce contamination.

Question 20

Which of the following best describes the role of John Snow in epidemiology?

Accepted Answer

He mapped a cholera outbreak and linked it to a contaminated water source.

Infection, Infectious Disease, and Epidemiology (Chapter 14) – Microbiology Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards