Symptoms by Stage — Hantavirus

Stage 1: Prodrome (1–8 weeks post-exposure)

The incubation period ranges from 1 to 8 weeks after exposure, most commonly 2–3 weeks. Initial symptoms are non-specific and mimic many common viral illnesses:

Fever (often 38–40°C / 101–104°F)
Severe fatigue and malaise
Myalgia (muscle aches), especially in the thighs, lower back, and shoulders
Headache
Dizziness
Gastrointestinal symptoms: nausea, vomiting, abdominal pain, diarrhoea

⚠ Critical warning

These symptoms mimic influenza, COVID-19, leptospirosis, sepsis, and other viral syndromes. The key differentiator is a history of rodent exposure in the preceding 1–8 weeks — cleaning barns, entering cabins, rural work, or known outbreaks in the area. Clinicians must ask about this exposure.

Stage 2a: Cardiopulmonary phase (HPS)

After 2–8 days of prodrome, HPS patients rapidly develop:

Cough (initially dry)
Dyspnoea (shortness of breath) progressing rapidly
Pulmonary edema — fluid filling the lungs (non-cardiogenic)
Hypotension and shock
Tachycardia (rapid heart rate)
Chest X-ray shows bilateral infiltrates resembling ARDS

This phase can progress from mild dyspnoea to respiratory failure requiring mechanical ventilation within hours. Without ICU care, mortality is extremely high.

Stage 2b: Renal phase (HFRS)

HFRS follows five clinical phases (not always distinct):

Febrile phase (3–7 days): fever, headache, myalgia, conjunctival injection
Hypotensive phase (hours–days): low blood pressure, shock, thrombocytopenia
Oliguric phase (3–7 days): decreased urine output, kidney injury, haemorrhage
Diuretic phase (days–weeks): recovery of kidney function, risk of fluid/electrolyte imbalance
Convalescent phase (weeks–months): gradual recovery

Stage 3: Recovery

Recovery from both HPS and HFRS is gradual:

HPS survivors: lung function typically recovers over weeks to months; some have long-term exercise intolerance
HFRS survivors: kidney function usually normalises but may take 3–6 months; some patients develop chronic kidney disease
Both: fatigue, weakness, and cognitive difficulties may persist for months

Sources

CDC. Signs & Symptoms: Hantavirus Pulmonary Syndrome (HPS). CDC Symptoms
Hjelle B, Torres-Pérez F. Hantaviruses in the Americas and their role as emerging pathogens. Antiviral Res 2010;85(3):417-426.
WHO. Hantavirus diseases: clinical management. WHO
Vial PA, et al. Hantavirus pulmonary syndrome due to Andes virus: clinical presentation and outcome. Clin Infect Dis 2006;42(5):e52-e57.