Hantavirus is endemic across Argentina, with Andes virus the predominant strain. 2026 case counts have nearly doubled year-on-year — the highest since 2018 — driven by climate-related rodent population shifts.
Argentina's Ministry of Health reported 101 hantavirus infections in the period from June 2025 through early May 2026 — roughly double the caseload recorded over the same period the previous year. The country is currently the focal point of international attention following the MV Hondius cluster, traced back to a pre-cruise bird-watching trip near a landfill outside Ushuaia.
Argentine authorities have launched a rodent-trapping program in Ushuaia and dispatched 2,500 diagnostic kits to laboratories in five countries to support international investigation. Authorities have not yet identified the precise exposure site of the Hondius index cases.
Andes virus circulates across four major endemic clusters in Argentina:
Public health researchers attribute the 2025-26 increase to several converging factors: warmer winters in the Andean foothills extending rodent breeding seasons, changes in agricultural land use bringing humans into closer contact with reservoir species, and improved diagnostic capacity surfacing cases that would previously have gone undetected.
"What we're seeing in Argentina is consistent with a regional ecological shift, not a sudden viral mutation. The virus hasn't changed — its host's range has."
| Year | Confirmed | Deaths | CFR | Notable events |
|---|---|---|---|---|
| 2026 YTD | 101 | 32 | 31.7% | MV Hondius origin |
| 2025 | 52 | 14 | 26.9% | Patagonia cluster (Q3) |
| 2024 | 63 | 19 | 30.1% | — |
| 2023 | 48 | 15 | 31.2% | — |
| 2018-19 | 142 | 38 | 26.7% | Epuyén person-to-person outbreak |
Sources: Argentina Boletín Epidemiológico Nacional · PAHO weekly bulletins · Ministerio de Salud Argentina