Q: Which of the following equations correctly represents the calculation of disease prevalence?

Prevalence = \frac{\text{Total number of cases (old + new)}}{\text{Population}}

Q: Which of the following is the correct formula for calculating disease incidence?

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

Question 1

Which of the following best describes mutualism in the context of the human microbiome?

Accepted Answer

Both the microbe and the human host benefit from the relationship.

Question 2

A patient is found to have Staphylococcus aureus on their skin, but shows no signs of infection. What type of symbiotic relationship does this most likely represent?

Accepted Answer

Commensalism

Question 3

Which of the following is an example of a nonliving reservoir for infectious disease?

Accepted Answer

Contaminated water

Question 4

Which mode of transmission is most likely responsible for the spread of influenza in a crowded classroom?

Accepted Answer

Droplet transmission

Question 5

A nurse touches a contaminated doorknob and then touches her face, leading to infection. What is the doorknob considered in this scenario?

Accepted Answer

Fomite

Question 6

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

Accepted Answer

Liver

Question 7

Which virulence factor allows bacteria to evade destruction by immune cells?

Accepted Answer

Antiphagocytic factors

Question 8

A person develops a disease after being bitten by a mosquito carrying the pathogen. What type of transmission is this?

Accepted Answer

Vector transmission

Question 9

Which of the following equations correctly represents the calculation of disease prevalence?

Accepted Answer

Prevalence = \frac{	ext{Total number of cases (old + new)}}{	ext{Population}}

Question 10

Which of the following best describes an opportunistic pathogen?

Accepted Answer

A microbe that causes disease only when the host's defenses are compromised.

Question 11

Which of the following is a correct statement about endotoxins?

Accepted Answer

Endotoxins are part of the cell wall of Gram-negative bacteria and can cause fever and shock.

Question 12

A patient is infected with a pathogen that enters through a cut in the skin. Which portal of entry is involved?

Accepted Answer

Parenteral route

Question 13

Which of the following scenarios best illustrates microbial antagonism?

Accepted Answer

Normal microbiota outcompete pathogens for nutrients, preventing infection.

Question 14

Which of the following is the correct formula for calculating disease incidence?

Accepted Answer

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

Question 15

Which of the following is an example of vehicle transmission?

Accepted Answer

Eating food contaminated with Salmonella

Question 16

A person with no symptoms carries and transmits a pathogen to others. What is this person called?

Accepted Answer

Carrier

Question 17

Which of the following is a critical difference between a reservoir and a fomite?

Accepted Answer

Reservoirs support microbial reproduction; fomites do not.

Question 18

Which of the following is a multi-step process that can lead to infection by an opportunistic pathogen?

Accepted Answer

Immune suppression followed by introduction of normal microbiota into an unusual site.

Question 19

Which of the following is most likely to result in a pandemic?

Accepted Answer

A disease that spreads rapidly across multiple continents.

Question 20

Which of the following best explains why biofilm formation is considered a virulence factor?

Accepted Answer

Biofilms protect microbes from host defenses and increase resistance to antibiotics.

Infection, Infectious Diseases, and Epidemiology (Chapter 14): Microbiology Study Notes

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