Viral Infections USMLE Step 1 Practice Question
A 10-month-old unvaccinated infant presents in January with profuse watery diarrhea and vomiting for 2 days. He appears lethargic with dry mucous membranes and sunken fontanelle. Vital signs show HR 128/min, RR 32/min, BP 85/55 mmHg, and temperature 38.2°C. Laboratory studies reveal serum sodium 128 mEq/L and elevated BUN-to-creatinine ratio. Stool culture is negative. Which organism is most likely responsible for this clinical presentation?
Answer choices
- AEnterotoxigenic Escherichia coli
- BAdenovirus
- CRotavirusCorrect answer
- DNorovirus
- EGiardia lamblia
- FVibrio cholerae
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