Hantavirus Symptoms
Last updated: May 9, 2026 · Sources: WHO, CDC, ECDC, MINSAL Chile
When to seek emergency care: If you have been in a hantavirus risk area (Patagonia, western US, etc.) in the past 8 weeks and develop fever + severe muscle aches + cough or difficulty breathing, seek emergency medical attention immediately and inform the doctor of your exposure history.
01
Phase 01 — Days 1–5
Prodrome phase
- →Fever (38–40°C / 100–104°F)
- →Intense muscle aches (myalgia)
- →Headache
- →Fatigue, malaise
- →Nausea, vomiting, abdominal pain (in ~50% of cases)
- →Chills
Clinically indistinguishable from influenza. This phase is critical for early identification if the patient reports recent rodent exposure or travel to endemic areas.
02
Phase 02 — Days 5–10
Cardiopulmonary phase
- →Dry cough
- →Rapidly progressive dyspnea (difficulty breathing)
- →Tachycardia, hypotension
- →Pulmonary edema (fluid in lungs)
- →Cardiogenic shock (in severe cases)
CRITICAL PHASE — most deaths occur here, within 24–48 hours of onset. Requires immediate ICU admission. ECMO (extracorporeal membrane oxygenation) has shown survival benefit in severe HPS cases in Chile.
03
Phase 03 — Days 10–14
Diuretic phase
- →Increased urine output (good prognostic sign)
- →Improvement in oxygenation
- →Resolution of pulmonary edema
- →Progressive stabilization
Patients who survive the cardiopulmonary phase enter this recovery phase. Close monitoring remains essential.
04
Phase 04 — Weeks to months
Convalescence phase
- →Persistent fatigue
- →Weakness
- →Possible neurological sequelae in some cases
- →Gradual return to normal activity
Full recovery may take weeks to months. Some patients report fatigue and exercise intolerance for extended periods.
Distinguishing HPS from flu
| Feature | HPS (Hantavirus) | Influenza |
|---|---|---|
| Onset | Gradual (3–5 day prodrome) | Abrupt |
| Cough | Dry, appears late | Common from early on |
| Breathing difficulty | Progressive, severe | Usually mild |
| Exposure history | Rodent contact / endemic area | Person-to-person |
| Sore throat | Rare | Common |
| GI symptoms | Frequent (nausea, vomiting) | Less common |
| Chest X-ray | Bilateral infiltrates | Usually normal |