Virology USMLE Step 1 Practice Questions
51 board-style USMLE Step 1 questions in Microbiology/Immunology. Each question shows the correct answer; create a free account for the full explanation and adaptive practice.
- USMLE Step 1 · medium1. A 55-year-old man with HIV infection has been on antiretroviral therapy for 3 years with a CD4+ count of 487 cells/μL and undetectable viral load until 6 months ago. He now pres…
- USMLE Step 1 · hard2. A 45-year-old man with a history of recurrent cold sores presents with severe blepharitis, conjunctivitis, and corneal dendritic ulcers confirmed by fluorescein staining. He has…
- USMLE Step 1 · easy3. A 4-year-old boy with acute onset of fever, cough, and inspiratory stridor is brought to the emergency department. He has not been vaccinated. Laryngoscopy reveals subglottic na…
- USMLE Step 1 · medium4. A 32-year-old woman with a 3-month history of progressive exertional dyspnea and nonproductive cough presents to the emergency department. She reports unintentional weight loss…
- USMLE Step 1 · medium5. A 67-year-old man with no significant past medical history presents to the emergency department with acute onset of severe burning pain in the right forehead and upper eyelid, f…
- USMLE Step 1 · medium6. A 14-day-old male infant born vaginally at 39 weeks gestation presents to the emergency department with vesicular rash on the scalp and eyelids, bilateral conjunctivitis, and re…
- USMLE Step 1 · medium7. A 19-year-old male college student presents to the emergency department with a 2-day history of fever (39.2°C), severe frontal headache, and neck stiffness. Physical examination…
- USMLE Step 1 · easy8. A 45-year-old man with no significant past medical history presents to the emergency department with a 2-week history of malaise, anorexia, and jaundice. He denies intravenous d…
- USMLE Step 1 · medium9. A 28-year-old woman with HIV infection (CD4 count 150 cells/μL) develops recurrent painful oral ulcers and is found to have esophageal ulcers on endoscopy. She is already on acy…
- USMLE Step 1 · easy10. A 6-year-old previously unvaccinated boy presents to the clinic with a 4-day history of fever (39.5°C), cough, coryza, and conjunctivitis. On examination, you note white spots w…
- USMLE Step 1 · easy11. A 32-year-old pregnant woman at 8 weeks gestation presents with fever (38.9°C), maculopapular rash on face and trunk, arthralgias, and cervical lymphadenopathy. Vital signs show…
- USMLE Step 1 · medium12. A 3-year-old girl with unknown vaccination status presents to the emergency department with a 4-day history of fever, bilateral parotid swelling, and jaw pain. Her temperature i…
- USMLE Step 1 · hard13. A 56-year-old male with a 20-year history of intravenous drug use presents to clinic with progressive fatigue, mild jaundice, and right upper quadrant discomfort. He denies alco…
- USMLE Step 1 · easy14. A 7-year-old boy presents to the clinic with a 3-day history of high fever (39.8°C), severe oral pain, and progressive dysphagia. His mother reports he attended summer camp 5 da…
- USMLE Step 1 · hard15. A 35-year-old man with a CD4+ count of 45 cells/μL presents to the emergency department with a 10-day history of profuse watery diarrhea (8-10 stools daily), severe crampy abdom…
- USMLE Step 1 · medium16. A 22-year-old woman at 8 weeks gestation presents to clinic with fever (38.8°C), arthralgias in her hands and feet, and a maculopapular rash that began on her face 2 days ago an…
- USMLE Step 1 · medium17. A 32-year-old woman with no significant past medical history presents to the emergency department with a 2-day history of severe bifrontal headache, photophobia, and neck stiffn…
- USMLE Step 1 · medium18. A 28-year-old woman with HIV infection presents with progressive blurred vision and floaters. Vital signs: BP 118/76, HR 92, RR 16, Temp 37.2°C, SpO2 98%. Laboratory studies sho…
- USMLE Step 1 · hard19. A 35-year-old previously healthy man develops sudden onset of severe headache, fever, neck stiffness, and altered mental status. CSF analysis shows lymphocytic pleocytosis with…
- USMLE Step 1 · medium20. A 72-year-old man with a 15-year history of COPD presents to the emergency department with a 3-day history of dyspnea, fever (38.9°C), and productive cough with purulent sputum.…
- USMLE Step 1 · hard21. A 45-year-old woman with a 10-year history of chronic hepatitis B (HBsAg positive, anti-HBc positive) presents to the emergency department with jaundice, right upper quadrant pa…
- USMLE Step 1 · medium22. A 28-year-old man with HIV/AIDS (CD4 count 45 cells/μL) presents with progressive cognitive decline, headache, and focal neurological deficits over two weeks. Vital signs: BP 11…
- USMLE Step 1 · medium23. A 32-year-old woman presents with fever, jaundice, and right upper quadrant pain for 5 days. She has a history of intravenous drug use. Laboratory studies show elevated transami…
- USMLE Step 1 · medium24. A 28-year-old man returns from Southeast Asia 3 weeks ago with severe cramping abdominal pain, profuse watery diarrhea, and diffuse myalgia. Vital signs show temperature 38.9°C,…