Virology USMLE Step 1 Practice Question
A 34-year-old woman presents to clinic with a 3-day history of fever (39.2°C), severe myalgia, and a maculopapular rash involving her palms and soles. She returned from a hiking trip in Colorado 10 days ago where she noted a tick bite on her leg. She denies any preceding rash at the bite site. Vital signs are notable for heart rate 92/min, blood pressure 118/76 mmHg, respiratory rate 16/min, and SpO2 98% on room air. Physical examination is otherwise unremarkable with no lymphadenopathy or hepatosplenomegaly. Laboratory studies show WBC 6,500/μL (normal), platelets 155,000/μL (mildly decreased), and a blood smear reveals spirochetes. Which of the following is the most likely causative organism?
Answer choices
- ABorrelia burgdorferi
- BRickettsia rickettsii
- CEhrlichia chaffeensis
- DBorrelia hermsiiCorrect answer
- EPowassan virus
- FAnaplasma phagocytophilum
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