Argentina Hantavirus Cases Nearly Double as Climate Change Fuels Rodent Spread

Argentina Hantavirus Cases Nearly Double as Climate Change Fuels Rodent Spread

Argentina is battling its worst hantavirus season in years, with confirmed infections nearly doubling compared to the previous year and 32 deaths recorded across the country. Health authorities and disease experts are pointing to climate change, habitat destruction, and shifting wildlife patterns as the primary forces driving the alarming rise.

The current season, which began in June 2025, has already seen 101 confirmed cases, according to Argentina’s Ministry of Health. That figure stands in stark contrast to the 57 cases recorded during the same period last season, representing a surge that has alarmed both domestic health officials and international observers.

The death toll reflects not only a rise in absolute numbers but also one of the highest fatality rates in recent years, with mortality increasing by ten percentage points compared to the prior season.

Adding an international dimension to the crisis, a deadly outbreak of hantavirus aboard the cruise ship MV Hondius has placed Argentina’s health response under global scrutiny. The vessel departed from the southern port city of Ushuaia on April 1, 2025, and is currently en route to Spain’s Canary Islands. The outbreak has been linked to the Andes strain of hantavirus, a particularly dangerous form of the virus that, unlike most strains, is capable of spreading between humans through close contact.

Argentine health authorities are working to trace the movements of a Dutch couple, both of whom died amid the shipboard outbreak, and who are believed to have traveled extensively through Argentina and into neighboring Chile and Uruguay before boarding the vessel. Officials suspect the pair may have been exposed to the virus during their travels through Misiones province in Argentina’s northeast and Neuquen in the south, both of which fall within the country’s historically high-risk regions.

However, Juan Petrina, director of epidemiology for Tierra del Fuego province, has raised questions about the timeline. Citing airport and departure records, he stated that the couple were in Ushuaia for only three days before the ship’s departure and dismissed speculation that they visited a local landfill site as unconfirmed.

The Ministry of Health has dispatched technical teams to Ushuaia to capture and analyze rodents in areas connected to the couple’s known route.

Climate Change at the Center of the Crisis

Hantavirus is typically transmitted through contact with the urine, feces, or saliva of infected rodents. In Argentina, the long-tailed mouse is the primary carrier of the virus. Experts say that rising temperatures and extreme weather events are fundamentally altering the behavior and distribution of this species, creating conditions in which the virus can spread more widely and in previously unaffected areas.

“Increasing human interaction with wild environments, habitat destruction, the establishment of small urbanizations in rural areas, and the effects of climate change contribute to the appearance of cases outside historically endemic areas,” Argentina’s Ministry of Health stated.

Eduardo Lopez, an infectious disease specialist who advised the Argentine government during the Covid-19 pandemic, noted that rodents are proving more adaptable to environmental shifts than other species. “These rodents are better able to adapt to climate changes, which could facilitate the higher number of cases we are seeing,” Lopez explained.

Roberto Debbag, vice president of the Latin American Society of Vaccinology, highlighted the role of forest fires in displacing both wildlife and human communities into new areas of contact. He also warned that tourism in risk zones poses a significant danger if those areas are not properly cleared of dense vegetation. “Anyone going to a risk area for tourism, if it is not cleared of undergrowth, represents a very high danger,” Debbag said.

Droughts and intense rainfall events, which have become more frequent in recent years, are also accelerating the trend by altering ecosystems in ways that favor rodent population growth and expansion.

A Shifting Geographic Pattern

For years, hantavirus in Argentina was most closely associated with Patagonia in the country’s southern reaches, following a deadly 2018 outbreak that killed 11 people and infected dozens more. This season, however, the disease has shifted significantly toward central Argentina. The province of Buenos Aires has recorded the highest concentration of cases, with 42 infections, marking a notable departure from historical patterns.

Four regions of Argentina are classified as historically high-risk: the Northwest, covering the provinces of Salta, Jujuy, and Tucuman; the Northeast, including Misiones, Formosa, and Chaco; the Central region, encompassing Buenos Aires, Santa Fe, and Entre Rios; and the South, spanning Neuquen, Rio Negro, and Chubut.

The geographic spread of this season’s cases beyond those traditional corridors underscores what experts describe as a new and more unpredictable phase of the disease’s presence in Argentina.

Health authorities continue to monitor the situation closely as both the domestic outbreak and the international investigation into the MV Hondius cruise ship incident develop. Officials have urged residents and tourists in at-risk areas to avoid contact with rodents and their habitats, particularly in rural, forested, and agricultural settings.