The dominant route — inhaled rodent dust
Every hantavirus has a specific rodent reservoir species in which it is asymptomatic and lifelong. Infected rodents shed virus in urine, droppings and saliva. When these dry and are disturbed — by a broom, a vacuum cleaner, a passing vehicle, a person crawling under a building — they aerosolise into a fine dust. Inhalation of that dust is the route of infection for over 95% of human hantavirus cases worldwide.
Other routes — bites and contaminated food
Direct rodent bites can transmit hantavirus, particularly Seoul virus from pet rats. Eating food contaminated with rodent droppings or urine is theoretically possible and has been suggested in a small number of HFRS clusters in rural China. Contact with contaminated surfaces followed by hand-to-face contact is also possible but documented less often than aerosol exposure.
Person-to-person transmission — the Andes-virus exception
Andes virus, endemic to Patagonia, is the only hantavirus species in which human-to-human transmission has been definitively documented. Family clusters were first reported in the 1996 El Bolsón outbreak. Roughly 12% of confirmed Andes-virus cases now trace to person-to-person spread, mostly among close household contacts and healthcare workers handling severe pulmonary cases. The May 2026 Atlantic cruise outbreak is the largest documented Andes-virus person-to-person event in twenty years.
Who is at highest risk
Occupational and lifestyle risk factors include: clearing rodent infestations from cabins, sheds, garages and seasonal dwellings; agricultural work (especially grain harvesting and silage handling); forestry and logging in vole-rich woodland; military field deployments; rodent breeding and pet-rat hobby; spelunking and back-country camping in rodent-rich shelters. Indoor living in sealed urban housing without rodent exposure carries negligible risk.