21. Principles of Disease

Indicate whether each statement is true or false. If the statement is false, change the underlined word or phrase to make the statement true.

_____ Relapse of fungal diseases is common in AIDS patients.

Tapeworms are generally transmitted via ______.

a. consumption of an intermediate host

b. consumption of the definitive host

c. vectors such as mosquitoes

d. consumption of adult tapeworms

Indicate the true statements and then correct the false statements so that they are true.

a. HIV is transmitted by a parenteral route.

b. Candida albicans is an opportunistic pathogen that can cause disease in an immune-competent host if the normal microbiota are disrupted.

c. Gram-positive bacteria may produce endotoxin.

d. Siderophores help pathogens obtain calcium.

e. Emerging pathogens tend to exhibit expanded tropism.

f. The more toxic a substance is, the higher its LD₅₀.

g. Virulence is the ability of a microbe to cause disease.

h. Gram-negative bacteria may produce exotoxins.