Host-Microbe Interaction

Question 1

Define infection.

Answer 1

(n.) the process whereby a microbe enters into a relationship with the host. It may or may not cause disease.

Question 2

What is an infectious disease, and how does it differ from an infection?

Answer 2

An infectious disease is a disease caused by an infection with a microbe.Some infections are communicable; others are not communicable and are not transmitted from patient to patient.

Question 3

Pathogens that affect all people equally are ________.

Answer 3

frank pathogens

Question 4

Pathogens that affect immunocompromised hosts are termed _________.

Answer 4

opportunistic pathogens

Question 5

Explain the distinction between mucous and mucus.

Answer 5

Mucus is a noun and refers to the substance secreted. Mucous is an adjective describing something (such as a “mucous membrane”).

Question 6

List Koch’s four postulates of infectious disease.

Answer 6

(1) the microbe is found in characteristic lesions of the disease; (2) the microbe can be isolated and cultured in vitro from lesions; (3) the microbe can be injected into animals to mimic the disease; and (4) the specific microbes can be re-isolated from the animals

Question 7

How is pathogenicity measured?

Answer 7

By examining the number of organisms required to be infectious in 50% of those inoculated (ID50), to produce disease in 50% of those inoculated (DD50), and to be lethal in 50% of those inoculated (LD50).

Question 8

Macrophages that reside in the skin are called ________.

Answer 8

Langerhans cells

Question 9

What is virulence?

Answer 9

The ability of a pathogen to cause disease in a host