Q: Which formula correctly calculates the prevalence of a disease in a population?

$\text{Prevalence} = \frac{\text{Number of old cases} + \text{Number of new cases}}{\text{Population}}$

Question 1

Which of the following best describes the relationship between a host and a parasite?

Accepted Answer

The parasite benefits at the expense of the host.

Question 2

A newborn is colonized by normal microbiota within 24-48 hours after birth. Which of the following is NOT a typical source of these microbes?

Accepted Answer

Sterile hospital air

Question 3

Which type of symbiotic relationship is illustrated when a fungus secretes an antibiotic that inhibits the growth of nearby bacteria?

Accepted Answer

Amensalism

Question 4

Which of the following is NOT a way that normal microbiota protect the host?

Accepted Answer

Increasing host susceptibility to pathogens

Question 5

A patient develops a yeast infection after taking antibiotics that kill lactobacilli in the vagina. Which category of normal flora becoming opportunists does this represent?

Accepted Answer

Changes in normal flora

Question 6

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

Accepted Answer

Contaminated water

Question 7

Which portal of entry is circumvented when a pathogen enters the body via a deep puncture wound?

Accepted Answer

Parenteral route

Question 8

Which of the following is required for a microorganism to successfully establish a colony within a host?

Accepted Answer

Adhesion to host cells

Question 9

A woman experiences nausea two days after eating raw oysters, then develops vomiting and diarrhea a week later. According to the stages of infectious disease, what stage is she in during the week of vomiting and diarrhea?

Accepted Answer

Illness

Question 10

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

Accepted Answer

Bacterial capsule

Question 11

Which of the following best describes the difference between exotoxins and endotoxins?

Accepted Answer

Exotoxins are secreted proteins, endotoxins are part of the Gram-negative cell wall.

Question 12

Which formula correctly calculates the prevalence of a disease in a population?

Accepted Answer

$	ext{Prevalence} = \frac{	ext{Number of old cases} + 	ext{Number of new cases}}{	ext{Population}}$

Question 13

Which stage of infectious disease is characterized by the absence of signs and symptoms, but the pathogen is present and multiplying?

Accepted Answer

Incubation period

Question 14

Which of the following is an example of a communicable disease?

Accepted Answer

Influenza spread by respiratory droplets

Question 15

A hospital patient develops a urinary tract infection from their own normal microbiota after catheterization. What type of healthcare-associated infection is this?

Accepted Answer

Endogenous

Question 16

Which of the following is NOT a mode of infectious disease transmission?

Accepted Answer

Genetic transmission

Question 17

Which of the following best describes a pandemic?

Accepted Answer

A worldwide epidemic

Question 18

Which of the following is a sign, rather than a symptom, of infectious disease?

Accepted Answer

Fever

Question 19

Which of the following is a correct statement about zoonoses?

Accepted Answer

Humans are usually dead-end hosts for zoonotic pathogens.

Question 20

Which of the following is a multi-step virulence factor process that allows bacteria to invade deeper tissues?

Accepted Answer

Production of hyaluronidase and collagenase

Chapter 14: Infection and Diseases – Microbiology Study Notes

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