The only hantavirus species with documented limited human-to-human transmission. Endemic to the southern cone of South America. Cause of the 2026 MV Hondius cluster.
| Reservoir host | Long-tailed pygmy rice rat (Oligoryzomys longicaudatus) |
| Geographic range | Argentina, Chile, Uruguay, southern Brazil |
| Disease syndrome | Hantavirus pulmonary syndrome (HPS) |
| Case fatality rate | ~35-40% |
| Incubation period | 1 to 6 weeks (median ~14-21 days) |
| Human-to-human | Documented but rare. Requires close, prolonged contact. |
| Vaccine | None licensed |
| Specific treatment | None. Supportive care, mechanical ventilation, ECMO. |
Primary transmission to humans occurs through aerosolization of dried rodent urine, feces, or saliva — typically when entering enclosed spaces (sheds, cabins, attics) where the long-tailed pygmy rice rat has been active.
Andes virus is the only hantavirus species with documented person-to-person transmission. In the 2018-19 Epuyén (Argentina) outbreak, the virus spread among guests at a birthday gathering and continued to propagate through household contact and at the funerary wake of the index case. The 2020 NEJM analysis of that outbreak concluded transmission required close, prolonged contact — typically intimate partners, household members, or healthcare workers without adequate PPE.
"Transmission between people has been associated with close and prolonged contact, particularly among household members, intimate partners and people providing medical care."
Andes virus infection follows a characteristic biphasic course:
Non-specific flu-like symptoms — fever, muscle aches, fatigue, headache, abdominal pain, nausea, vomiting. Often misdiagnosed as gastroenteritis or influenza at this stage. The early symptoms are generic enough that exposure history is essential for clinical suspicion.
Rapid progression to pulmonary edema, acute respiratory distress syndrome (ARDS), hypotension, and cardiogenic shock. Mortality is concentrated in this phase. Survivors typically begin diuresis 3-5 days into the cardiopulmonary phase, signaling recovery.
Andes virus circulates across four major endemic zones:
Andes virus has very limited pandemic potential despite its capacity for human-to-human transmission. The basic reproduction number (R0) in human-to-human chains is well below 1 in nearly all settings, meaning sustained transmission cannot occur. Even the largest documented person-to-person cluster (Epuyén 2018-19) produced 34 cases over several months and resolved without further spread.
For Andes virus to acquire epidemic potential it would need fundamental changes in transmission biology — efficient respiratory droplet or aerosol spread between strangers, with shorter incubation. No such mutations have been documented despite decades of surveillance.