Exam 11: Travelers Diarrhea: Identifying the Causative Agent

Bacteria are protected from phagocytosis by

A 6-month-old child has had watery diarrhea for 6 days. The stools have no blood and no pus. The causative agent has double-stranded RNA as genetic material. Which of the following is the most likely causative agent?

Which of the following is the principal immunoglobulin (Ig) in exocrine secretions?

Which of the individuals listed below is the most likely to develop a serious disease from West Nile virus?

If a series of drug resistance genes are transferred together routinely, what is the most likely method of transfer?

In question 17, the substance found in the patient's CSF that gives the positive agglutination test also plays a role in the pathogenesis. What is that role?

A 12-day-old neonate is brought in because of parental concern about eye redness and "watering" associated with the conjunctiva of both eyes. Visual examination confirms and also detects several vesicles. Appropriate topical treatment is with

In June, an 18-year-old man develops a sore throat with a fever and a nonproductive cough that develops into pneumonia with a severe, prolonged hacking cough but little sputum production. Cryoagglutinins are present. He is treated appropriately and successfully with azithromycin. What is the nature of the most likely causative agent?

A 50-year-old woman from Key West presents with a mosquito-borne viral disease in which her antiviral antibodies from an infection nearly a decade ago were thought to have an "enhancing" effect so that the current reinfection with the virus caused a more serious bleeding disease. What is the causative agent?

A 26-year-old woman presents with diarrhea containing both blood and pus. The lab cultures on a special medium incubated at 42°C under microaerophilic conditions grow a Gram-negative spiral-shaped organism that is isolated. What is the most likely genus?

A preschool day care has reported that the majority of the children are complaining of very sore throats. A closer examination of the situation indicates that they also have slight fevers and vesicular lesions (some of which have ulcerated) on their tonsillar and pharyngeal mucosa. The most likely cause is

The genetic mechanism responsible for the conversion of a nontoxigenic strain of Corynebacterium diphtheriae to a toxigenic strain is