Q: Which of the following equations correctly represents the calculation of attack rate in an epidemic investigation?

$Attack\ Rate = \frac{\text{Number\ of\ new\ cases}}{\text{Population\ at\ risk}} \times 100$

Question 1

Which of the following best describes a pandemic disease?

Accepted Answer

A disease that spreads across countries and continents, affecting a large number of people globally.

Question 2

Koch's postulates are a set of criteria used to establish a causative relationship between a microbe and a disease. Which of the following is NOT one of Koch's postulates?

Accepted Answer

The microorganism must be able to mutate rapidly to evade the immune system.

Question 3

A patient develops a fever and rash after being bitten by a mosquito carrying a virus. In this scenario, what role does the mosquito play in disease transmission?

Accepted Answer

Vector

Question 4

Which of the following best illustrates mutualism in the human body?

Accepted Answer

E. coli in the gut synthesizing vitamin K for the host while receiving nutrients.

Question 5

A hospital-acquired infection is best described as a(n):

Accepted Answer

Nosocomial infection

Question 6

Which of the following immune cells is primarily responsible for phagocytosis of bacteria during the early stages of infection?

Accepted Answer

Neutrophil

Question 7

A person receives a vaccine and develops immunity to a disease. This is an example of:

Accepted Answer

Artificially acquired active immunity

Question 8

Which of the following best explains why antibodies have so much genetic diversity?

Accepted Answer

Antibody genes undergo somatic recombination and hypermutation.

Question 9

A patient is exposed to rabies and receives both HRIG (human rabies immunoglobulin) and the rabies vaccine. What type of immunity is this?

Accepted Answer

Artificially acquired passive immunity combined with active immunity

Question 10

Which of the following is the most efficient and cost-effective way to control infectious disease in a population?

Accepted Answer

Vaccination

Question 11

A blood test is performed to detect the presence of antibodies against a specific pathogen. This type of analysis is called:

Accepted Answer

Serology

Question 12

Which of the following best describes the function of a pattern recognition receptor (PRR) on a macrophage?

Accepted Answer

Recognizes conserved microbial structures such as lipopolysaccharide.

Question 13

A patient receives a mismatched blood transfusion and develops fever, nausea, and vomiting. What is the most likely cause?

Accepted Answer

The recipient had previously been exposed to foreign blood group antigens.

Question 14

Which of the following best describes the difference between antigenic drift and antigenic shift in influenza viruses?

Accepted Answer

Antigenic drift involves small point mutations, while antigenic shift involves large-scale genetic reassortment.

Question 15

Which of the following equations correctly represents the calculation of attack rate in an epidemic investigation?

Accepted Answer

$Attack\ Rate = \frac{	ext{Number\ of\ new\ cases}}{	ext{Population\ at\ risk}} 	imes 100$

Question 16

A newborn receives antibodies from its mother through breast milk. This is an example of:

Accepted Answer

Naturally acquired passive immunity

Question 17

Which of the following best describes the role of a reservoir in infectious disease transmission?

Accepted Answer

A reservoir is any person, animal, plant, soil, or substance in which an infectious agent normally lives and multiplies.

Question 18

Which of the following statements about endotoxins is correct?

Accepted Answer

Endotoxins are part of the outer membrane of Gram-negative bacteria and can cause fever and shock.

Question 19

A person is exposed to a pathogen and develops symptoms after a few days. The period between exposure and onset of symptoms is called:

Accepted Answer

Incubation period

Question 20

Which of the following best describes the function of interferons in the immune response?

Accepted Answer

They are signaling proteins that help protect neighboring cells from viral infection.

Unit 3 Exam Study Guide

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