Syndromes
Two diseases, one virus family
Hantaviruses cause two clinically very different syndromes depending on which virus is involved and which side of the world it lives on. The New World viruses target the lungs; the Old World viruses target the kidneys and blood vessels.
HPS — Hantavirus Pulmonary Syndrome
Caused by New World hantaviruses (Sin Nombre, Andes, Bayou, Black Creek Canal, New York virus, Choclo and others) found in the Americas. Sin Nombre is the dominant cause in the United States; Andes virus dominates Argentina and Chile.
| Virus | Reservoir | Region | Case-fatality |
|---|---|---|---|
| Sin Nombre (SNV) | Deer mouse (Peromyscus maniculatus / sonoriensis) | Western US, Canada | 30–50% |
| Andes (ANDV) | Long-tailed pygmy rice rat | Argentina, Chile | ~30–40% |
| Bayou | Marsh rice rat | SE United States | ~50% (small series) |
| Black Creek Canal | Hispid cotton rat | Florida | High; very rare |
| New York virus | White-footed mouse | NE United States | — |
| Choclo / Laguna Negra | Pygmy rice rats | Panama, Paraguay, Bolivia | Variable |
Clinical course
- Incubation: typically 1–8 weeks (median ~2–3) after exposure.
- Prodromal phase (1–5 days): fever, severe muscle pain (especially thighs and back), headache, GI upset. Often mistaken for the flu.
- Cardiopulmonary phase: within 24–48 hours of any pulmonary symptoms, fluid floods the lungs (non-cardiogenic edema), oxygen drops and blood pressure collapses. Death usually comes 2–10 days after symptom onset, from refractory shock and hypoxia.
- Diuretic / convalescent phases: rapid clearance of pulmonary edema; full recovery of strength can take weeks to months.
HPS lab triad
Three blood-test findings together strongly suggest HPS in someone with the right exposure:
- Thrombocytopenia — low platelets.
- Circulating immunoblasts — atypical large lymphocytes >10%.
- Hemoconcentration — rising hematocrit because plasma is leaking out of vessels.
HFRS — Hemorrhagic Fever with Renal Syndrome
Caused by Old World hantaviruses across Eurasia. Severity ranges from the very mild "nephropathia epidemica" (Puumala) to severe Hantaan and Dobrava infections.
| Virus | Reservoir | Region | Case-fatality |
|---|---|---|---|
| Hantaan (HTNV) | Striped field mouse (Apodemus agrarius) | China, Korea, Russian Far East | 5–15% |
| Dobrava-Belgrade (DOBV) | Yellow-necked mouse / striped field mouse | Balkans, Central & Eastern Europe | up to ~10–12% |
| Seoul (SEOV) | Brown rat (worldwide) | Global, including pet-rat clusters in US/UK | <1–2% |
| Puumala (PUUV) | Bank vole (Myodes glareolus) | N / Central Europe (esp. Finland, Scandinavia, Germany) | <0.4% |
The classic five phases of HFRS
- Febrile (3–7 d): sudden fever, muscle pain, headache, conjunctival injection, petechiae, flushed face/neck.
- Hypotensive (hours – 2 d): capillary leak, shock; ~one-third of deaths happen here.
- Oliguric (3–7 d): acute kidney injury, low or no urine output, hemorrhage, hypertension. Most deaths cluster in this phase.
- Diuretic (days – weeks): massive urine output (3–6 L/day), risk of dehydration and electrolyte collapse.
- Convalescent (weeks – months): renal function gradually returns.
Diagnosis
- Serology (mainstay): IgM-capture ELISA usually positive at symptom onset; rising IgG titers confirm.
- Molecular: RT-PCR on whole blood / serum during early viremia; sequencing identifies the species.
- Tissue: Immunohistochemistry of formalin-fixed lung tissue detects N-protein antigen.
Treatment
- HPS: aggressive ICU support — careful fluid management, vasopressors, mechanical ventilation; early ECMO raises survival to ~80% in CDC reports.
- HFRS: supportive care plus hemodialysis if needed. IV ribavirin reduces mortality if started in the first 4–7 days of severe Hantaan/Dobrava disease and is used in China. Ribavirin trials in HPS have not shown benefit.
- No specific antiviral is licensed in the US or EU. No vaccine in the US/EU; inactivated HFRS vaccines licensed in South Korea (Hantavax) and China. More on vaccines →
Mortality at a glance
| Syndrome / virus | Case-fatality rate |
|---|---|
| HPS overall (US, 1993–2023) | ~35% (309/890) |
| HPS, Sin Nombre | 30–50% |
| HPS, Andes | ~30–40% |
| HFRS, Hantaan | 5–15% (modern ~3% in China) |
| HFRS, Dobrava | up to ~10–12% |
| HFRS, Seoul | <1–2% |
| HFRS, Puumala (NE) | <0.4% |
Frequently asked questions
What are the first symptoms of hantavirus?
Fever, severe muscle pain in thighs and back, headache, nausea and vomiting. Sore throat and runny nose are usually absent.
What is the incubation period for hantavirus?
HPS: 1–8 weeks (median 2–3). HFRS: typically 2–4 weeks.
Is hantavirus curable? Does it go away on its own?
No specific cure. Mild Puumala HFRS often resolves with supportive care. Severe HPS will not resolve without ICU support.
Can hantavirus cause pneumonia?
It causes non-cardiogenic pulmonary edema, not classic bacterial pneumonia. Antibiotics don't help.
Does hantavirus cause a rash, sore throat or diarrhea?
Petechiae can appear in HFRS. Sore throat is usually absent. GI symptoms — nausea, vomiting, abdominal pain, sometimes diarrhea — are common early.
What is the survival rate of hantavirus pulmonary syndrome?
About 65% overall in US data; up to ~80% with early ECMO.
See Transmission for how it spreads, Prevention for cleanup guidance, and Hantavirus vs flu for differential diagnosis.