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Reference

How hantavirus spreads

The vast majority of human infections come from rodents, not from other people. Here is how — and the one important exception.

Primary route — aerosolised rodent excreta

Rodents shed hantaviruses in their urine, droppings and saliva. When dried excreta are disturbed (sweeping, cleaning, vacuuming, walking on contaminated surfaces), small particles become aerosolised and can be inhaled. This is the dominant route of human infection for every hantavirus that causes human disease.

High-risk settings:

  • Cabins, sheds, barns and storerooms left closed for months.
  • Wood piles, grain stores, hay barns.
  • Cleaning rodent-infested vehicles, tents, garages.
  • Rural agricultural work in endemic regions.
  • Outdoor occupations involving disturbance of dust (forestry, road maintenance).

Secondary routes

  • Bites — rare, but documented. Direct rodent bite can introduce virus through the wound.
  • Mucosal contact — touching a contaminated surface and then rubbing eyes, nose or mouth.
  • Ingestion — consuming food contaminated by rodent excreta is a recognised but uncommon route.

Person-to-person transmission — only Andes virus

Andes virus (ANDV), the principal HPS-causing hantavirus in southern Argentina and Chile, is the only hantavirus with confirmed human-to-human transmission. Documented cases have occurred in close-contact settings — household contacts, healthcare workers without adequate PPE, sexual partners. Cluster outbreaks (Epuyén, Argentina, 2018–2019) have been driven by such transmission.

For all other hantaviruses — Sin Nombre, Seoul, Hantaan, Puumala, Dobrava-Belgrade, Choclo, Laguna Negra and others — there is no evidence of person-to-person spread under normal conditions, including in healthcare settings.

Reservoir species (where the virus actually lives)

  • Sin Nombre → deer mouse (Peromyscus maniculatus) — North America.
  • Andes → long-tailed pygmy rice rat (Oligoryzomys longicaudatus) — southern South America.
  • Seoul → brown rat (Rattus norvegicus) — worldwide via shipping and urban populations.
  • Hantaan → striped field mouse (Apodemus agrarius) — East Asia.
  • Puumala → bank vole (Myodes glareolus) — Northern and Central Europe.
  • Dobrava-Belgrade → yellow-necked mouse (Apodemus flavicollis) — Balkans, Central Europe.

Each virus is highly host-specific. Knowing the local reservoir species explains much of the local geography of risk.

What does not transmit hantavirus

  • Mosquitoes, ticks, fleas, lice — hantaviruses are not vector-borne.
  • Casual person-to-person contact — handshakes, sharing food (except ANDV in close-contact clusters).
  • Aerosols generated by infected humans — hantaviruses are not respiratory viruses in the COVID/influenza sense, with the narrow exception above.
  • Drinking water from sealed sources — although well water in rodent-contaminated areas warrants caution.

Sources: CDC Hantavirus, ECDC Factsheet, peer-reviewed studies on Andes virus transmission (Padula et al. 1998; Martinez et al. 2020). See /sources.