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

$$ \text{Prevalence} = \frac{\text{Total number of cases}}{\text{Total population}} $$

Question 1

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

Accepted Answer

The microbe benefits while the host is neither harmed nor benefited.

Question 2

A patient develops a urinary tract infection after being hospitalized. This is an example of which type of infection?

Accepted Answer

Nosocomial infection

Question 3

Which of the following is a correct statement about normal microbiota?

Accepted Answer

Normal microbiota can become opportunistic pathogens under certain conditions.

Question 4

Which of the following is an example of a zoonosis?

Accepted Answer

Rabies transmitted from a dog to a human

Question 5

A microbe must first attach to host cells to establish infection. Which term describes the molecules on the microbe that mediate this attachment?

Accepted Answer

Ligand

Question 6

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

Accepted Answer

Liver

Question 7

Which stage of infectious disease is characterized by the most severe signs and symptoms?

Accepted Answer

Illness period

Question 8

A scientist is studying the spread of a new disease in a population. She records the number of new cases per month. Which epidemiological term best describes this measurement?

Accepted Answer

Incidence

Question 9

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

Accepted Answer

Capsule

Question 10

Which of the following transmission routes is most likely responsible for the spread of cholera in a community?

Accepted Answer

Waterborne transmission

Question 11

A hospital is trying to reduce the incidence of nosocomial infections. Which of the following interventions is most effective?

Accepted Answer

Improving hand hygiene among staff

Question 12

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

Accepted Answer

Incidence is the number of new cases, while prevalence is the total number of cases.

Question 13

Which of the following is a limitation of Koch's postulates?

Accepted Answer

They cannot be used for diseases caused by viruses that require a human host.

Question 14

A patient is infected with a bacterium that produces coagulase. What is the likely effect of this enzyme?

Accepted Answer

It forms clots to protect the bacteria from host defenses.

Question 15

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

Accepted Answer

$$ 	ext{Prevalence} = \frac{	ext{Total number of cases}}{	ext{Total population}} $$

Question 16

Which of the following scenarios best illustrates an opportunistic infection?

Accepted Answer

An immunocompromised patient develops a fungal infection from normal microbiota.

Question 17

Which of the following is a mechanical vector for disease transmission?

Accepted Answer

Housefly carrying bacteria on its legs

Question 18

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

Accepted Answer

The period of mild, general symptoms before the illness becomes severe

Question 19

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

Accepted Answer

Fever

Question 20

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

Accepted Answer

$$ 	ext{Incidence} = \frac{	ext{Number of new cases}}{	ext{Total population}} $$

Ch 14 lecture

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