An encapsulated bacterium can be virulent because the capsule
a. resists phagocytosis.
b. is an endotoxin.
c. destroys host tissues.
d. kills host cells.
e. has no effect; because many pathogens do not have capsules, capsules do not contribute to virulence.

Name one fungus and one protozoan that can cause genital system infections. What symptoms would lead you to suspect these infections?

Using the following data, draw a graph showing the incidence of influenza during a typical year. Indicate the endemic and epidemic levels.

Use the following information to answer questions 8–10.

A Maryland woman was hospitalized with dehydration. V. cholerae and Plesiomonas shigelloides were isolated from the patient, who had neither traveled outside the United States nor eaten raw shellfish during the preceding month. The patient had attended a party before hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding with coconut milk. Crabs left over from this party were served at a second party. One of the people at the second party had onset of mild diarrhea; specimens from of these people were negative for vibriocidal antibodies.

The source of the disease was

a. Plesiomonas shigelloides.

b. crabs.

c. V. cholerae.

d. coconut milk.

e. rice.

This microbe is acquired by humans as infants and is essential for good health. Acquiring a closely related strain causes severe stomach cramps, bloody diarrhea, and vomiting. What is the microbe?