$$\text{Prevalence} = \frac{\text{Total number of cases}}{\text{Population at risk}}$$

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

Question 1

Which type of symbiotic relationship is exemplified by bacteria in the human colon, where both organisms benefit?

Accepted Answer

Mutualism

Question 2

A patient is found to have Staphylococcus on their skin, but there are no signs of disease. What type of symbiotic relationship is this?

Accepted Answer

Commensalism

Question 3

Which of the following is NOT a reason why transient microbiota cannot persist in the body?

Accepted Answer

They are always pathogenic

Question 4

During which stage of infectious disease are the most severe signs and symptoms observed?

Accepted Answer

Illness

Question 5

Which portal of entry is most commonly used by respiratory pathogens?

Accepted Answer

Mucous membranes

Question 6

A newborn acquires its resident microbiota primarily during which process?

Accepted Answer

Birthing process

Question 7

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

Accepted Answer

Bacterial capsule

Question 8

What is the term for the number of new cases of a disease in a given area during a given period of time?

Accepted Answer

Incidence

Question 9

Which of the following is an example of a zoonosis?

Accepted Answer

Rabies acquired from a dog bite

Question 10

A patient develops an infection after a surgical procedure. What type of nosocomial infection is this?

Accepted Answer

Iatrogenic

Question 11

Which equation correctly represents the calculation of prevalence?

Accepted Answer

$$	ext{Prevalence} = \frac{	ext{Total number of cases}}{	ext{Population at risk}}$$

Question 12

Which of the following is NOT a characteristic of exotoxins?

Accepted Answer

Released only when bacteria die

Question 13

A researcher is unable to culture a suspected pathogen in the laboratory. Which of Koch’s postulates cannot be satisfied?

Accepted Answer

The agent must be isolated and grown in pure culture

Question 14

Which of the following is a real-world example of vehicle transmission?

Accepted Answer

A person contracts hepatitis from contaminated water

Question 15

Which term describes a disease that is always present at a low level in a population?

Accepted Answer

Endemic

Question 16

What is the primary function of hyaluronidase and collagenase as extracellular enzymes?

Accepted Answer

To dissolve structural chemicals and allow invasion of deeper tissues

Question 17

Which of the following is a plausible scenario for an opportunistic infection?

Accepted Answer

Normal microbiota introduced into an unusual site in the body

Question 18

Which equation best represents the calculation of incidence?

Accepted Answer

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

Question 19

Which of the following is the most effective way to reduce nosocomial infections in a hospital setting?

Accepted Answer

Hand washing

Question 20

A disease characterized by symptoms and signs that are felt only by the patient is best described as:

Accepted Answer

Symptom

Infection, Infectious Diseases, and Epidemiology: Microbial Interactions and Disease Transmission

Study Guide - Practice Questions