The hantavirus involved in the MV Hondius episode — the Andes virus — is just one species among 38 in the ICTV 2024 classification of the genus Orthohantavirus. The family Hantaviridae groups, worldwide, 60 distinct viruses associated with specific rodents and insectivores (shrews, moles). This page is an overview of the main strains that cause human disease, their geography, clinical severity and animal reservoirs.
Two main clinical families
Before drilling into individual strains, remember a clinical distinction that structures all global hantavirus epidemiology:
1. Hantavirus pulmonary syndrome (HPS)
- Geography: Americas (North and South).
- Main strains: Sin Nombre (USA, Canada), Andes (Argentina, Chile), Bayou, Black Creek Canal, Laguna Negra, Choclo.
- Biological target: lungs. Massive lesional pulmonary oedema and cardiogenic shock.
- Case fatality: high, 30 to 40%.
- Reservoirs: Sigmodontinae rodents (deer mouse, long-tailed pygmy rice rat, marsh rice rat).
2. Haemorrhagic fever with renal syndrome (HFRS)
- Geography: Eurasia (Russia, Scandinavia, Balkans, China, Korea).
- Main strains: Hantaan, Seoul, Puumala, Dobrava-Belgrade, Saaremaa.
- Biological target: kidneys. Haemorrhage, acute renal failure.
- Case fatality: variable by strain, from < 1% to 15%.
- Reservoirs: Murinae rodents (striped field mouse, brown rat, bank vole).
A third, milder form is the nephropathia epidemica (NE) — attenuated HFRS variant, mostly linked to Puumala virus in northern Europe and Russia.
American strains (HPS)
Sin Nombre virus (SNV) — Orthohantavirus sinnombreense
- Distribution: western North America, from Mexico to Alaska. Incidence peak in the Four Corners region (Arizona, Colorado, New Mexico, Utah), where the disease was identified in 1993.
- Reservoir: deer mouse (Peromyscus maniculatus).
- Human cases: 30-50 confirmed cases per year in the United States per CDC.
- Case fatality: 30 to 35%.
- Person-to-person transmission: not documented.
- Comparison with Andes: very close genome (~ 80% similarity), same clinical syndrome, slightly lower fatality.
Andes virus (ANDV) — Orthohantavirus andesense
See the dedicated Andes virus article for full details. In short:
- Distribution: southern South America (Argentina, Chile).
- Reservoir: long-tailed pygmy rice rat (Oligoryzomys longicaudatus).
- Case fatality: ~ 40%.
- Specificity: only hantavirus for which person-to-person transmission is documented by a formal study (NEJM 2020, Epuyén outbreak).
Bayou, Black Creek Canal, Laguna Negra
Minor American strains, responsible for a small number of cases each:
| Strain | Reservoir | Distribution | Cases/year |
|---|---|---|---|
| Bayou (O. bayoui) | Marsh rice rat (O. palustris) | US Southeast (Louisiana, Florida) | < 5 |
| Black Creek Canal | Cotton rat (Sigmodon hispidus) | US Southeast | < 5 |
| Laguna Negra | Patagonian rodent | Paraguay, Bolivia, Argentina | a few dozen |
| Choclo | Oligoryzomys fulvescens | Panama | few |
All produce HPS with a case fatality comparable to Sin Nombre virus (30 to 40%).
Eurasian strains (HFRS)
Hantaan virus (HTNV) — Orthohantavirus hantanense
- Distribution: East Asia (China, Korea, Russian Far East). Most severe HFRS form.
- Reservoir: striped field mouse (Apodemus agrarius).
- Human cases: China alone reports tens of thousands of confirmed cases per year (the most affected country globally for human hantaviruses, all strains combined). The virus is named after the Hantan River in South Korea, where it was first isolated in 1976.
- Case fatality: 5 to 15%.
- Vaccine: an inactivated vaccine (Hantavax®) is used in South Korea.
Seoul virus (SEOV) — Orthohantavirus seoulense
- Distribution: worldwide, follows the dispersion of commensal rats. Found wherever Rattus norvegicus (brown rats) live.
- Reservoir: brown rat (Rattus norvegicus), black rat (R. rattus).
- Specificity: only hantavirus with a global distribution in urban areas, due to the commensalism of its reservoirs.
- Case fatality: < 1% (mildest HFRS form together with Puumala).
- Human cases: sporadic almost everywhere, more frequent in East Asia.
Puumala virus (PUUV) — Orthohantavirus puumalaense
- Distribution: Northern Europe (Sweden, Norway, Finland), Baltic states, European Russia, western Central Europe, France (Ardennes, Lorraine, Franche-Comté).
- Reservoir: bank vole (Myodes glareolus), abundant in mixed European forests.
- Human cases: France records between 70 and 200 confirmed cases per year (Santé publique France), with cyclic peaks driven by vole population fluctuations. Most common human hantavirus disease in mainland France.
- Case fatality: < 0.5% (mild form, called nephropathia epidemica).
- Clinical picture: fever + acute transient renal failure, usually reversible.
Dobrava-Belgrade virus (DOBV) — Orthohantavirus dobravaense
- Distribution: Balkans (Slovenia, Bosnia, Serbia, North Macedonia), Central and Eastern Europe (Hungary, Slovakia, eastern Germany, Russia).
- Reservoir: yellow-necked mouse (Apodemus flavicollis), striped field mouse (A. agrarius) depending on subtype.
- Case fatality: 5 to 12% (severe HFRS form, comparable to Hantaan).
- Human cases: a few hundred per year for the endemic area.
Saaremaa virus (SAAV)
Strain related to Dobrava, distributed in Estonia, European Russia, Germany and Scandinavia. Milder clinical form than Dobrava (< 1% CFR, closer to Puumala).
Emerging and atypical strains
The genus Orthohantavirus keeps growing: the ICTV 2024 taxonomic revision reclassified several strains previously considered variants, and new sequences are regularly described in non-rodent hosts (shrews, moles):
- Thottapalayam hantavirus (India) — first hantavirus isolated from a shrew (Suncus murinus), no documented human case.
- Nova hantavirus (Eurasia) — in moles (Talpa), no documented human case.
- Khabarovsk, Tula, Topografov, Vladivostok hantaviruses (Russia, Asia) — in various rodents, very rare or unconfirmed human cases.
These strains are monitored for their zoonotic potential but do not significantly contribute to the current human disease burden.
Summary table
| Strain | ICTV species | Syndrome | Geography | Reservoir | CFR |
|---|---|---|---|---|---|
| Andes | O. andesense | HPS | AR, CL | Long-tailed pygmy rice rat | ~ 40% |
| Sin Nombre | O. sinnombreense | HPS | USA, CA, MX | Deer mouse | 30-35% |
| Hantaan | O. hantanense | HFRS | CN, KR, RU | Striped field mouse | 5-15% |
| Dobrava | O. dobravaense | HFRS | Balkans, Central Europe | Yellow-necked mouse | 5-12% |
| Puumala | O. puumalaense | NE (mild HFRS) | N. Europe, RU, FR | Bank vole | < 0.5% |
| Seoul | O. seoulense | Moderate HFRS | Worldwide (urban) | Brown rat | < 1% |
| Saaremaa | O. saaremaaense | Moderate HFRS | N. Europe | Striped field mouse | < 1% |
| Bayou | O. bayoui | HPS | US Southeast | Marsh rice rat | 30-40% |
| Laguna Negra | O. lagunanegraense | HPS | PY, BO, AR | Patagonian rodents | 30-40% |
Global disease-burden distribution
- China: ~ 20,000 to 100,000 confirmed cases per year, mostly Hantaan + Seoul (Heilongjiang, Jilin, Liaoning, Shaanxi, Shandong, Hubei provinces). Most affected country in the world, by far.
- Russia: several thousand cases/year, Puumala + Dobrava mix.
- Scandinavia + Baltic states: hundreds of cases/year, Puumala dominant.
- Western Europe: France, Germany, Belgium — a few hundred cases/year, Puumala.
- Balkans: hundreds of cases/year, Dobrava + Puumala.
- North America: 30-50 cases/year in the USA (Sin Nombre), a few cases/year in Canada.
- South America: < 100 cases/year (Argentina + Chile), Andes dominant.
The 2026 MV Hondius cluster remains exceptional in two ways: (1) it documents the first maritime cluster for a hantavirus, (2) it combines Andes virus and on-board person-to-person transmission within a confined environment of 149 people for 40 days, never observed before.
Learn more
- Glossary — Hantavirus: general definition.
- Glossary — Andes virus: detailed factsheet.
- Glossary — Hantavirus pulmonary syndrome (HPS): American form.
- Glossary — Haemorrhagic fever with renal syndrome (HFRS): Eurasian form.
- Article — Andes virus: phylogeny, transmission, 2026 sequencing: focus on the MV Hondius strain.