Question 1

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

Accepted Answer

Both the microbe and the host benefit from the relationship.

Question 2

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

Accepted Answer

They are eliminated by the body’s defense cells or outcompeted by resident microbiota.

Question 3

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

Accepted Answer

A superinfection

Question 4

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

Accepted Answer

Liver

Question 5

A newborn develops microcephaly and blindness after the mother contracts Toxoplasma gondii during pregnancy. Which portal of entry did the pathogen most likely use?

Accepted Answer

Placenta

Question 6

Which of the following best explains why a mutated strain of Streptococcus pneumoniae that cannot produce a capsule is avirulent?

Accepted Answer

It cannot evade phagocytosis by host immune cells.

Question 7

Which of the following is a correct statement about exotoxins and endotoxins?

Accepted Answer

Exotoxins are proteins with high toxicity, while endotoxins are lipid A components of LPS with lower toxicity.

Question 8

A patient is diagnosed with a disease that is easily spread from person to person. Which term best describes this disease?

Accepted Answer

Contagious

Question 9

Which of the following is an example of vehicle transmission?

Accepted Answer

A person develops cholera after drinking contaminated water.

Question 10

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

Accepted Answer

Incidence is the number of new cases in a given period, while prevalence is the total number of cases in a given period.

Question 11

A hospital patient develops a urinary tract infection from a catheter inserted during surgery. This infection is best classified as:

Accepted Answer

An iatrogenic infection

Question 12

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 13

Which of the following is a correct application of Koch’s postulates?

Accepted Answer

A suspected pathogen must be present in every case of the disease and absent from healthy individuals.

Question 14

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

Accepted Answer

A mosquito transmitting Plasmodium spp. during a blood meal

Question 15

A disease that develops slowly and lasts a long time with usually mild symptoms is best described as:

Accepted Answer

Chronic

Question 16

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

Accepted Answer

It kills hosts quickly, reducing the chance for widespread transmission.

Question 17

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

Accepted Answer

Fever

Question 18

Which of the following best explains why not all arthropod vectors are considered reservoirs?

Accepted Answer

Some vectors only transmit pathogens without supporting their multiplication or development.

Question 19

A patient is infected with a pathogen but does not show any symptoms. However, laboratory tests reveal the presence of the pathogen. This infection is best described as:

Accepted Answer

Asymptomatic (subclinical)

Question 20

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

Accepted Answer

Handwashing by healthcare workers

Infection, Infectious Diseases, and Epidemiology: Core Concepts and Mechanisms

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