Deck 10: The Nature of Disease: a Pathogens Perspective

Question 1

In terms of how a pathogen might affect a host, which of the following is the correct sequence of events?

A) contamination » disease » infection
B) disease » contamination » infection
C) infection » contamination » disease
D) infection » disease » contamination
E) contamination » infection » disease

Answer 1

E

Question 2

Streptokinase, coagulase, and hemolysins are all examples of:

A) exotoxins.
B) endotoxins.
C) tissue degrading enzymes.
D) viral cytopathic effects.

Answer 2

C

Question 3

In a latent viral infection:

A) there is rapid viral replication in an infected cell.
B) there is slow viral replication in an infected cell.
C) there is no viral replication in an infected cell.
D) numerous inclusion bodies are visible in the cytoplasm of an infected cell.
E) we expect oncogenes to be activated, leading to tumor formation.

Answer 3

C

Question 4

Eradication of any pathogen is very unlikely unless that pathogen uses:

A) human reservoirs only.
B) animal reservoirs only.
C) environmental reservoirs only.
D) human or animal reservoirs.
E) animal or environmental reservoirs.

Question 5

How does our normal flora protect us from some infections by pathogens?

Question 6

Which of the following statements is true about endotoxins?

A) They all work in different ways.
B) They are all proteins.
C) They are only produced by Gram-negative bacteria.
D) They are only produced by Gram-positive bacteria.
E) They interfere with host ribosomes, blocking protein synthesis by host cells.

Question 7

The portal of exit for pathogens:

A) is always the same as the portal of entry.
B) is always different from the portal of entry.
C) may or may not be the same as the portal of entry.
D) is a critical requirement if the pathogen is to cause disease.
E) is lacking in almost all human diseases.

Question 8

Which of the following is false about exotoxins?

A) Part of the exotoxin called the "A subunit" binds to receptors on the surface of certain host cells.
B) The combined exotoxin (both the A & B subunits) enter the host cell by endocytosis.
C) They may be produced by either Gram-positive or Gram-negative bacteria.
D) They are generally more toxic than endotoxins at low concentration.
E) They are composed of protein.

Question 9

If a disease is described as a "zoonosis", what type of reservoir do we expect the pathogen causing the disease to utilize?

A) human
B) animal
C) environmental
D) both "a" and "b"
E) both "b" and "c"

Question 10

What is the difference between biological vector transmission and mechanical vector transmission?

Question 11

For a given pathogen:

A) the ID₅₀ will always be lower than the LD_50.
B) the ID₅₀ will always be higher than the LD_50.
C) the ID₅₀ and the LD₅₀ will always be equal.
D) the ID₅₀ may be lower or higher than the LD_50.

Question 12

The time period between infection and the onset of symptoms is called:

A) an inapparent infection.
B) the period of disease.
C) the incubation period.
D) the recovery period.
E) the threshold period.

Question 13

Why are symptoms in a host, such as diarrhea in the case of intestinal disease, or sneezing and coughing in the case of respiratory disease, beneficial from the perspective of some pathogens that cause these diseases?