In humans, Sin Nombre virus infection is associated with which clinical finding?

• A. Renal failure
• B. Gastrointestinal bleeding
• C. Pulmonary pathology
• D. Neurological symptoms

Answer: (C)

Sin Nombre virus causes hantavirus pulmonary syndrome, a severe respiratory illness. The defining clinical finding is pulmonary pathology—rapid onset of fever and dyspnea with noncardiogenic pulmonary edema and hypoxemia that can progress to respiratory failure. This is why pulmonary involvement is the best answer. In contrast, other hantaviruses in different regions cause hemorrhagic fever with renal syndrome, where renal failure is prominent; GI bleeding or neurological symptoms are not typical features of Sin Nombre virus infection. Remember that exposure is usually from inhaling aerosolized rodent excreta, and the lung-stage pathology drives the clinical picture.