How hantavirus is diagnosed in the laboratory

Hantavirus diagnosis combines clinical suspicion with laboratory confirmation. Because hantavirus mimics other severe respiratory or febrile illnesses early on, diagnosis often starts retrospectively. Primary tests: 1. Serology (most common): detects IgM antibodies appearing within days of symptom onset, persisting for months, alongside IgG that signals past or recurring infection. ELISA-based commercial kits exist for Sin Nombre, Puumala, Hantaan, and a few other species. Strip immunoblot assay can confirm and distinguish species. 2. RT-PCR: detects viral RNA in serum or whole blood during the early viremic phase (first 7-10 days). High specificity. Useful when serology is negative but suspicion is high. Reference labs typically run species-specific primers (e.g., Andes, Hantaan, Sin Nombre). 3. Immunohistochemistry: post-mortem confirmation on lung, heart, kidney, and lymphoid tissue. Reserved for fatal cases without antemortem diagnosis. Reference laboratories: - Argentina: INEI-ANLIS Carlos G. Malbrán, Buenos Aires. - Chile: ISP (Instituto de Salud Pública), Santiago. - USA: CDC Special Pathogens Branch, Atlanta. - Europe: ECDC reference network plus national labs (Charité in Germany, Karolinska in Sweden, etc.). Sample handling: Serum or plasma in standard tubes for serology. EDTA whole blood for RT-PCR. Most national systems require notification on suspicion (do not wait for confirmation). Differential diagnosis includes leptospirosis, dengue, severe community-acquired pneumonia, septic shock from other causes, and — in HFRS regions — leptospirosis and severe rickettsiosis. A travel history and exposure history (rural work, rodent contact) are diagnostic gold.