Viral Infections USMLE Step 1 Practice Question
A 6-year-old unvaccinated boy presents with a 4-day history of high fever (39.8°C), cough, coryza, and conjunctivitis. Physical examination reveals a descending maculopapular rash on the trunk and small blue-white lesions with red halos on the buccal mucosa. Vital signs show tachycardia (HR 118/min), tachypnea (RR 28/min), and oxygen saturation of 96% on room air. Lymph node enlargement is absent. Which organism is most likely responsible?
Answer choices
- ARubella virus
- BHuman herpesvirus 6
- CMumps virus
- DParainfluenza virus
- EMeasles virusCorrect answer
- FVaricella-zoster virus
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