Bacterial Toxins And Immune Evasion Practice Test

A 6-year-old unimmunized child who recently immigrated to the United States is brought to the clinic with a severe sore throat, fever, and malaise. Physical examination reveals a thick, gray, adherent pseudomembrane over the tonsils and pharynx. Several days later, the child develops signs of heart failure and arrhythmias. The systemic effects are caused by a bacterial exotoxin.

A 28-year-old man returns from a humanitarian trip to a region with a known cholera epidemic. He develops abrupt onset of profuse, watery diarrhea described as 'rice-water stool,' along with vomiting and severe dehydration. His stool sample contains no leukocytes or erythrocytes. His symptoms are caused by an enterotoxin that dramatically alters intestinal fluid secretion.