Question 1

Which of the following best describes the relationship between the human body and its normal microbiota in the colon?

Accepted Answer

Mutualism, because both the bacteria and the host benefit from the interaction.

Question 2

Which of the following is a plausible consequence of a baby being delivered by Caesarian section rather than vaginal birth?

Accepted Answer

The baby will have a higher risk of developing autoimmune diseases such as type I diabetes.

Question 3

Which of the following is an example of a nonliving reservoir of infection?

Accepted Answer

Soil contaminated with Clostridium tetani spores.

Question 4

A patient presents with fever, rash, and vomiting. Which of the following best describes these manifestations?

Accepted Answer

Fever, rash, and vomiting are all signs, because they can be observed or measured by others.

Question 5

Which of the following best explains why an acute disease with a high mortality rate is unlikely to cause a pandemic?

Accepted Answer

High mortality prevents widespread transmission because infected hosts die quickly.

Question 6

Which of the following is a correct statement about the rhizosphere microbiome?

Accepted Answer

It is the narrow region of soil influenced by root secretions and associated with nitrogen-fixing bacteria.

Question 7

Which of the following is a plausible reason why normal microbiota can become opportunistic pathogens?

Accepted Answer

Introduction into an unusual site in the body.

Question 8

Which of the following best describes the difference between incidence and prevalence?

Accepted Answer

Incidence is the number of new cases during a specific period, while prevalence is the total number of cases at a given time.

Question 9

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

Accepted Answer

A mosquito transmitting Plasmodium to a human host.

Question 10

Which of the following best describes the function of bacterial virulence factors such as hyaluronidase?

Accepted Answer

They digest hyaluronic acid, which binds host cells together, facilitating tissue invasion.

Question 11

A patient is infected with a pathogen but does not show any symptoms. However, laboratory tests reveal the presence of the pathogen. What is the best term for this type of infection?

Accepted Answer

Asymptomatic (subclinical) infection

Question 12

Which of the following is a correct example of commensalism?

Accepted Answer

Mites living in human hair follicles without affecting the host

Question 13

Which of the following best describes the effect of breast-feeding on the infant microbiome?

Accepted Answer

Breast milk contains carbohydrates that feed beneficial microbiota, such as Bifidobacterium longum infantis.

Question 14

Which of the following is the best definition of a zoonosis?

Accepted Answer

A disease that naturally spreads from animal hosts to humans.

Question 15

Which of the following is a correct statement about exotoxins?

Accepted Answer

They are proteins secreted by bacteria and can be produced by both Gram-positive and Gram-negative bacteria.

Question 16

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

Accepted Answer

The period with vague, general symptoms before the illness phase.

Question 17

Which of the following is a plausible outcome if a person is exposed to a dose of Mycobacterium tuberculosis lower than the infectious dose (ID)?

Accepted Answer

The person is unlikely to develop an infection.

Question 18

Which of the following is a correct example of a vehicle transmission of disease?

Accepted Answer

Transmission of Salmonella through contaminated drinking water.

Question 19

Which of the following best describes herd immunity?

Accepted Answer

Immunity in most of a population, reducing the spread of disease.

Question 20

Which of the following is a correct definition of a primary infection?

Accepted Answer

An initial infection within a given patient.

Normal Flora, Symbiosis, and Infectious Disease: Microbiome and Epidemiology

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