Question 1

Which of the following best describes the difference between 'infection' and 'infectious disease' as defined by microbiologists?

Accepted Answer

Infection refers to colonization by a pathogen, which may or may not result in disease; infectious disease refers to the actual occurrence of disease caused by the pathogen.

Question 2

A patient is exposed to 50 Shigella cells and 500 Salmonella cells. Based on the concept of virulence, which pathogen is more likely to cause disease and why?

Accepted Answer

Shigella, because it is more virulent and requires fewer cells to cause disease.

Question 3

Which of the following is NOT considered a virulence factor that enables pathogens to attach, escape destruction, or cause disease?

Accepted Answer

Mitochondria

Question 4

A patient develops bacterial pneumonia after recovering from a mild viral respiratory infection. This is an example of:

Accepted Answer

A primary infection followed by a secondary infection

Question 5

Which of the following best describes the role of pili (fimbriae) in bacterial pathogenesis?

Accepted Answer

They enable bacteria to attach to host tissues, acting as virulence factors.

Question 6

Which of the following is an example of a zoonotic disease and its mode of transmission?

Accepted Answer

Lyme disease transmitted by ticks (arthropod vector)

Question 7

Which of the following is a correct sequence of steps in the pathogenesis of infectious diseases?

Accepted Answer

Entry, attachment, multiplication, invasion, evasion of host defenses, damage to host tissues

Question 8

Which of the following mechanisms allows pathogens to evade the host immune response?

Accepted Answer

Antigenic variation

Question 9

A patient with herpes simplex virus experiences periods of symptoms followed by periods without symptoms, then symptoms return. This pattern is best described as:

Accepted Answer

Latent infection

Question 10

Which of the following is an example of a fomite and its role in disease transmission?

Accepted Answer

A contaminated hospital bedspread transmitting pathogens to patients

Question 11

Which of the following is a major difference between endotoxins and exotoxins?

Accepted Answer

Endotoxins are part of the cell wall of Gram-negative bacteria, while exotoxins are secreted proteins by various pathogens.

Question 12

Which of the following equations best represents the relationship between the infectious dose ($ID_{50}$) and virulence?

Accepted Answer

$Virulence \propto \frac{1}{ID_{50}}$

Question 13

Which of the following is an example of microbial antagonism?

Accepted Answer

Indigenous microbiota inhibiting the growth of foreign microbes at a body site

Question 14

Which of the following is a correct description of an obligate intracellular pathogen?

Accepted Answer

A pathogen that must live within host cells to survive and multiply, such as Rickettsia spp.

Question 15

Which of the following is NOT a component of the chain of infection?

Accepted Answer

Antibiotic resistance

Question 16

A patient is diagnosed with miliary tuberculosis, which has spread throughout the body. This is an example of:

Accepted Answer

A systemic (generalized) infection

Question 17

Which of the following is a mechanism by which Haemophilus influenzae can evade host immune defenses?

Accepted Answer

Production of IgA protease to destroy host antibodies

Question 18

Which of the following best describes a chronic infectious disease?

Accepted Answer

A disease with a slow onset and long duration, such as tuberculosis

Question 19

Which of the following is an example of molecular mimicry as a virulence strategy?

Accepted Answer

Schistosomes coating themselves with host proteins to avoid immune detection

Question 20

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

Accepted Answer

Elevated blood pressure

Pathogenesis of Infectious Diseases – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards