Side-by-side comparison
| Hantavirus | influenza | |
|---|---|---|
| Pathogen | Influenza A/B virus (Orthomyxoviridae) | Hantavirus (Hantaviridae) |
| Transmission | Respiratory droplets between humans | Aerosolised rodent droppings |
| Prodrome | Fever, myalgia, fatigue (1–4 days) | Fever, severe myalgia, headache (3–7 days) |
| Severe phase | Mostly avoided; pneumonia in elderly/immunocompromised | Pulmonary edema or kidney injury in 100% of severe cases |
| Person-to-person | Highly efficient | Almost never (Andes virus exception) |
| Antiviral | Oseltamivir, baloxavir | Ribavirin (HFRS only) |
| Vaccine | Annual reformulated vaccine, widely available | China/Korea only for Hantaan/Seoul |
| CFR | ~0.1% globally | 0.4–36% by species |
| Annual burden | 290k–650k deaths globally (WHO) | Tens of thousands of cases worldwide |
The diagnostic trap
In the first three to seven days, hantavirus is functionally identical to influenza on clinical exam: fever, severe muscle aches, headache, sometimes nausea and vomiting. The blood work begins to diverge — hantavirus typically drops platelets and raises haematocrit during the prodrome — but those signals are often missed unless the clinician already suspects hantavirus. Patients are routinely sent home with "flu" and return days later in respiratory failure.
When to suspect hantavirus instead of flu
Three exposure-based triggers should redirect the diagnosis: (1) recent rodent contact in a closed structure (cabin, shed, barn); (2) seasonal/geographical fit — late spring/summer in the western US, late summer in northern Europe, austral summer in Patagonia; (3) outbreak alert — when WHO publishes a regional DON, clinicians within the catchment should add hantavirus to the differential. The 2026 cruise outbreak prompted exactly this kind of catchment alert.