Question

Which of the following statements about virulence factors is true?

a. they always activate host defenses.
b. they increase the ability of a pathogen to cause disease.
c. they are found in nonpathogenic strains of a microbe as well as pathogenic strains.
d. they are defined as being any genes that are required for microbial survival.

Answer 1

Virulence factors are specialized elements within a pathogen that enhance its capacity to cause disease, with the correct statement being that they increase the ability of a pathogen to cause disease.

Step-by-step explanation:

Virulence factors are those elements within a pathogen that amplify its capacity to cause disease. The correct statement about virulence factors is that b. they increase the ability of a pathogen to cause disease. These factors can be physical entities, like a surface protein that aids in binding to host cells or mechanisms that facilitate immune evasion. Virulence factors are encoded by specific genes, and when inactivated, can diminish a pathogen's virulence. However, these factors are not necessarily involved in activating host defenses nor are they found in all strains. Importantly, virulence factors are not just any genes required for microbial survival; they are specific to enhancing disease-causing ability.