Virology USMLE Step 1 Practice Question
A 3-month-old infant is hospitalized in winter with bronchiolitis. Vital signs show temperature 38.2°C, heart rate 160/min, respiratory rate 58/min, and oxygen saturation 88% on room air. Chest X-ray reveals hyperinflation with peribronchial infiltrates. Nasal swab PCR is positive for respiratory syncytial virus. WBC count is 11,200/μL. The patient denies fever or rash prior to respiratory symptoms. Which viral property most directly contributes to multinucleated giant cell formation in infected respiratory epithelium?
Answer choices
- AFusion protein that causes syncytiaCorrect answer
- BNeuraminidase
- CReverse transcriptase
- DLatency in sensory ganglia
- EHemagglutinin that binds sialic acid
- FSegmented RNA genome allowing reassortment
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