Hantavirus Transmission — Primary, Secondary, and Person-to-Person Routes
Hantaviruses are rodent-borne. Humans are accidental, dead-end hosts for almost every serotype. Transmission is overwhelmingly via inhalation of aerosolised rodent excreta in enclosed spaces. Andes virus is the sole exception — it has documented person-to-person transmission, primarily between close household contacts.
Primary route: rodent-to-human aerosol
Infected rodents shed virus in urine, faeces, and saliva. When dried excreta is disturbed — by sweeping, vacuuming, or vehicle movement in a barn or cabin — virus-laden particles aerosolise and can be inhaled. Risk is highest in poorly-ventilated, rodent-infested structures: cabins, outbuildings, grain stores, agricultural sheds, abandoned vehicles, military barracks, and rodent-occupied apartments.
Secondary routes
- Direct rodent bite — rare, but documented for Seoul virus from pet rats in the US and UK.
- Mucous-membrane contact — eye-rubbing after handling rodent material is a plausible inoculation route.
- Contaminated food — possible but rare; not a mainstream transmission mode.
- Laboratory exposure — historical lab outbreaks during early hantavirus research; modern BSL-3 containment makes this rare.
Andes virus person-to-person transmission
Andes virus (ANDV) is the only orthohantavirus with documented P2P transmission. Cluster evidence comes from:
- El Bolsón, Argentina (1996) — Wells et al. described 20 cases linked through close-contact transmission, including healthcare workers and household contacts.
- Coyhaique, Chile (2018–2019) — sequenced clusters showing inter-person transmission between non-household close contacts.
- MV Hondius cluster (2026) — actively monitored. Onboard spread is suspected given the long voyage and shared crew quarters; HORIZON ontology models this explicitly under the "transmitted_to" relationship between the index couple.
P2P transmission appears to require close, prolonged contact rather than fleeting exposure. Universal precautions, droplet isolation for known/suspected ANDV cases, and respirator use during aerosol-generating procedures are recommended by Argentine and Chilean health authorities during active outbreaks.
What does NOT transmit hantavirus
- Mosquitoes, ticks, or any arthropod vector — hantaviruses are not arboviruses despite the "haemorrhagic fever" naming.
- Casual contact with HPS/HFRS patients (except for ANDV close contacts) — this is not an airborne respiratory virus in the SARS-CoV-2 sense.
- Food prepared in non-rodent-contaminated kitchens.
- Blood transfusion (no documented cases).
- Sexual transmission (no documented cases).
Reservoir species — primary rodent hosts
| Serotype | Reservoir | Region |
|---|---|---|
| ANDV | Oligoryzomys longicaudatus (long-tailed pygmy rice rat) | Argentina, Chile, southern Patagonia, Tierra del Fuego |
| SNV | Peromyscus maniculatus (deer mouse) | United States Four Corners region, Canada, Mexico |
| PUUV | Myodes glareolus (bank vole) | Scandinavia, Baltic states, central Europe, European Russia |
| HTNV | Apodemus agrarius (striped field mouse) | China, Korean peninsula, far-eastern Russia |
| SEOV | Rattus norvegicus (brown rat), Rattus rattus (black rat) | Worldwide via global Rattus distribution |
| DOBV | Apodemus flavicollis (yellow-necked mouse) | Balkans, central Europe, European Russia |
| BAYV | Oryzomys palustris (marsh rice rat) | Southeastern United States |
| LANV | Calomys laucha (small vesper mouse) | Paraguay, Bolivia, Argentina |
See prevention for evidence-based measures to reduce exposure risk in endemic regions.
How hantavirus is transmitted — full route inventory
The dominant route for every hantavirus serotype is inhalation of aerosolised rodent excreta. The mechanism is well-characterised: the virus is shed in rodent urine, faeces, and saliva, which dry on indoor surfaces; mechanical disturbance (sweeping, vacuuming without HEPA, moving old furniture, lifting stored items) aerosolises the contaminated dust; humans inhale the aerosolised particles. A small inoculum is sufficient.
| Route | Documented for which serotypes | Relative frequency |
|---|---|---|
| Inhalation of aerosolised excreta | All serotypes | Dominant route (estimated >95%) |
| Direct rodent bite | SNV, ANDV, SEOV, HTNV | Rare |
| Hand-to-mucosa via contaminated surface | All serotypes | Documented but uncommon |
| Contaminated food or water | Theoretically possible; few documented cases | Very rare |
| Person-to-person, household close contact | Andes virus only | Rare even for ANDV; well-documented in Argentine and Chilean clusters |
| Laboratory exposure (needle-stick, droplet) | All serotypes — BSL-3 pathogen | Rare; managed under strict containment |
| Vertical (mother to fetus/newborn) | ANDV | Rare; few documented cases during peri-partum maternal viraemia |
Reservoir species — who carries which strain
Hantaviruses co-evolved with specific rodent species over millions of years. The relationship is so tight that the virus phylogeny mirrors the host phylogeny almost exactly. This means hantavirus risk is fundamentally geographic: you can only catch the virus where the reservoir species lives.
| Serotype | Primary rodent reservoir | Endemic geography |
|---|---|---|
| Sin Nombre (SNV) | Deer mouse (Peromyscus maniculatus) | USA, Canada, northern Mexico — particularly the Four Corners region (Arizona, Colorado, New Mexico, Utah) |
| Andes (ANDV) | Long-tailed pygmy rice rat (Oligoryzomys longicaudatus) | Southern Chile and Argentina, Magallanes, Aysén, Patagonia |
| Puumala (PUUV) | Bank vole (Myodes glareolus) | Northern, central, and eastern Europe; Scandinavia (highest incidence in Finland, Sweden, Belgium) |
| Hantaan (HTNV) | Striped field mouse (Apodemus agrarius) | China, Korea, Russian Far East |
| Seoul (SEOV) | Brown rat (Rattus norvegicus) | Worldwide via global shipping; severe disease most often in Asia |
| Dobrava-Belgrade (DOBV) | Yellow-necked mouse (Apodemus flavicollis) | Balkans, central and eastern Europe |
| Laguna Negra (LANV) | Vesper mouse (Calomys laucha) | Paraguay, Bolivia, Argentina, Brazil |
| Choclo (CHOV) | Costa Rican pygmy rice rat (Oligoryzomys fulvescens) | Panama |
| Bayou (BAYV) | Marsh rice rat (Oryzomys palustris) | Southeastern USA |
| Black Creek Canal (BCCV) | Cotton rat (Sigmodon hispidus) | Florida, southeastern USA |
Andes virus person-to-person transmission — the special case
Andes virus is the only orthohantavirus with documented human-to-human transmission. The mechanism remains under investigation; current evidence supports respiratory droplet and direct contact during the acute prodromal and cardiopulmonary phases. The 1996 Argentine outbreak in El Bolsón, the 2018 Epuyén outbreak, and the 2026 MV Hondius cluster all show clear within-household secondary transmission chains, with secondary cases typically presenting 14-25 days after the primary case.
Practical implications:
- Patients with confirmed or suspected ANDV-HPS must be cared for under droplet and contact precautions, with negative-pressure isolation where available.
- Healthcare workers attending ANDV-HPS patients should use FFP3/N95 respirators, eye protection, gowns, and gloves.
- Household contacts of confirmed cases should self-isolate from vulnerable people (children, elderly, immunocompromised) until cleared by public-health follow-up.
- Routine social and workplace contact does not require restriction for asymptomatic contacts.
- The MV Hondius 2026 cluster prompted the UK Health Security Agency (UKHSA) and ECDC to update clinical guidance on ANDV contact tracing.
What is NOT a hantavirus transmission route
Despite persistent online misinformation, hantavirus is NOT transmitted by:
- Mosquito or tick bites. Hantaviruses are not arthropod-borne. Vector-borne haemorrhagic fevers (dengue, Crimean-Congo, Rift Valley) are entirely separate viral families.
- Domestic pets. Dogs, cats, hamsters, guinea pigs, and rabbits are not hantavirus reservoirs. The myth that pet hamsters carry hantavirus is false — pet hamsters can rarely carry Seoul virus if exposed to wild brown rats, but this requires unusual circumstances.
- Air conditioning systems. Hantaviruses do not survive or replicate in HVAC ducting. Aerosol transmission requires a rodent-fouled source (excreta), proximity, and disturbance.
- Sexual contact (other than ANDV close-contact transmission, which is not specifically sexual). No documented hantavirus serotype is sexually transmitted in the conventional sense.
- Blood donation. Hantavirus is not listed as a transfusion-transmissible pathogen in any major blood-service screening panel. Asymptomatic viraemia is too brief for routine blood-supply concern.
- Drinking water (public supply). Municipal water treatment readily inactivates the virus. Risk would be limited to severely contaminated raw water sources.
Hantavirus survival outside the host
Hantavirus survival in the environment depends sharply on conditions. Laboratory studies indicate:
- In dried rodent excreta at room temperature, the virus remains viable for approximately 2-3 days.
- In cool, moist, dark conditions (rodent-fouled basements, sheds, cabins), viability can extend to over a week.
- UV light (direct sunlight) inactivates the virus within hours.
- Heating to 60°C for 30 minutes inactivates it reliably.
- 10% bleach solution (1 part household bleach to 9 parts water) is the CDC-recommended disinfectant for contaminated surfaces.
- 70% ethanol and standard quaternary-ammonium disinfectants are also effective.
Travel and transmission risk by region
Use HORIZON's country pages for current authoritative-source case counts and risk assessments. A summary of where travellers are at elevated risk:
- USA — Four Corners region (Arizona, Colorado, New Mexico, Utah). Sin Nombre virus. Risk peaks in spring and summer when deer mice populations are high.
- Chile and Argentina — southern Patagonia (Magallanes, Aysén, Neuquén, Río Negro). Andes virus. Risk year-round but peaks in summer (December-March) with peak rodent activity.
- Scandinavia — Finland, Sweden, Norway. Puumala virus. Risk peaks in autumn and winter when bank voles enter buildings.
- Germany, Belgium, Netherlands, France. Puumala virus, cyclical outbreak years driven by oak/beech mast cycles affecting bank vole populations.
- China, Korea. Hantaan virus, seasonal peak in late autumn during rice harvest.
- Russian Far East. Hantaan and Seoul virus.
- Balkans — Serbia, Bosnia, Croatia, Slovenia. Dobrava-Belgrade and Puumala virus.
- Paraguay, Bolivia, Brazil northern Argentina. Laguna Negra and Andes virus.
Frequently asked questions
Is hantavirus contagious between people?
With one exception, hantaviruses do not transmit between people. The exception is Andes virus (ANDV), endemic to southern South America, which has documented person-to-person transmission via close household contact during the acute illness. All other hantaviruses — Sin Nombre, Puumala, Hantaan, Seoul, Dobrava-Belgrade — are rodent-to-human only.
How do you catch hantavirus from a rodent?
The primary route is inhaling aerosolised dust contaminated with rodent urine, faeces, or saliva. This typically happens in enclosed spaces (sheds, cabins, barns, basements) when contaminated dust is disturbed by sweeping, vacuuming without a HEPA filter, moving stored items, or renovating. Direct rodent bites and contaminated food/water are minor secondary routes.
Can you catch hantavirus from a hamster or pet?
Pet hamsters, guinea pigs, dogs, cats, and rabbits do not carry hantavirus under normal circumstances and are not reservoirs. The only documented exception is pet brown rats or pet hamsters that have been exposed to wild brown rats carrying Seoul virus — these cases are extremely rare and have been documented mainly in the UK and US among rat-breeder communities.
Can mosquitoes spread hantavirus?
No. Hantaviruses are not arthropod-borne. Mosquitoes, ticks, fleas, and midges do not carry or transmit hantavirus. Other rodent-associated diseases (e.g. Lyme, plague) involve arthropod vectors, but hantavirus is strictly an aerosol/contact pathogen.
How long does hantavirus survive on surfaces?
In dried rodent excreta at room temperature, hantavirus remains viable for approximately 2-3 days. In cool, moist, dark conditions (basements, rodent-fouled sheds), viability can extend to over a week. UV light inactivates the virus within hours. A 10% household bleach solution is the CDC-recommended disinfectant.
Why is Andes virus the only hantavirus that spreads between people?
The molecular basis is not fully resolved, but Andes virus has structural differences in its glycoproteins that allow it to replicate to higher titres in respiratory tissue compared to other hantaviruses. This produces more infectious respiratory droplets during the acute illness, enabling household transmission. Multiple Argentine and Chilean outbreaks have documented clear secondary case chains starting 14-25 days after the primary case.
Can you get hantavirus from drinking contaminated water?
Hantavirus transmission via drinking water is theoretical and has not been convincingly documented as a major route. Municipal water-supply treatment inactivates the virus. Risk would be limited to severely contaminated raw water sources (e.g. an unfiltered cistern with rodent access). The dominant route remains inhalation of aerosolised excreta.
Is hantavirus airborne?
Hantavirus is not airborne in the epidemiological sense of measles or tuberculosis — it does not float in room air or travel between rooms via HVAC. It IS aerosolised by mechanical disturbance of contaminated dust, producing a short-range aerosol that infects people in immediate proximity to the source. Practical implication: opening up a long-closed cabin without dampening the dust first is the classic high-risk scenario.
Can a doctor or nurse catch hantavirus from a patient?
For all hantaviruses except Andes virus, no. For ANDV-HPS, yes — healthcare worker secondary cases have been documented, prompting standard droplet + contact precautions, FFP3/N95 respirator use, and where possible negative-pressure isolation. The MV Hondius 2026 cluster led UKHSA and ECDC to issue updated occupational guidance on ANDV contact precautions.
Where in the world is hantavirus most common?
Hantavirus is endemic across most temperate and tropical regions, with specific high-incidence pockets: USA Four Corners (Sin Nombre); southern Chile and Argentina (Andes); Scandinavia and Germany (Puumala); China and Korea (Hantaan); the Balkans (Dobrava-Belgrade). See HORIZON's country pages for current authoritative-source case counts.