The number of hantavirus infections in Argentina has nearly doubled in the past year, with the country recording its highest number of infections since 2018 and 32 deaths.
The increase comes as Argentine authorities scramble to trace the footprints of a couple who traveled extensively in the country and then died amid a virus outbreak aboard the cruise ship MV Hondius, which left Argentina’s southern port of Ushuaia on April 1 and is currently heading to Spain’s Canary Islands.
Experts attribute the rise in the disease to climate change and habitat destruction, which is usually caused by exposure to the urine or feces of infected rodents.
According to Argentina’s Ministry of Health, there have already been 101 confirmed cases of hantavirus this season, which began in June 2025, compared to just 57 during the same period last season.
The country not only recorded an unusually high number of infections this year, it also recorded the highest fatality rate in recent years, with deaths increasing by 10 percentage points compared to the previous year.
And these numbers do not include the outbreak on the cruise ship MV Hondius, whose cause remains unknown.
The ministry said no cases of hantavirus had been recorded in Ushuaia in recent decades, but the virus is endemic in some other parts of Argentina.
Argentine authorities believe the couple crossed the border with neighboring Chile multiple times before joining the cruise, and visited various parts of the country when they entered Uruguay.
Four geographic regions in Argentina have historically been at high risk of infection. These are the northwest (Salta, Jujuy, and Tucuman), the northeast (Misiones, Formosa, and Chaco), the center (Buenos Aires, Santa Fe, and Entre Rios), and the south (Neuquen, Rio Negro, and Chubut).
The Dutch couple who died in an outbreak on board the ship are believed to have visited both Misiones and Neuquén provinces during their trip.
Hantavirus has long been linked to Patagonia, in Argentina’s southern tip, after a deadly outbreak in 2018 killed 11 people and infected dozens.
However, most cases this season have been found in the country’s central region, with Buenos Aires province having the highest number of infections at 42.
The outbreak on board the ship is thought to be related to the Andean strain of hantavirus. Hantaviruses are rare but potentially serious viruses that can be transmitted between humans through close contact in some cases.
Argentine hantaviruses typically occur in rural and peri-urban areas with agricultural crops, tall weeds, moisture, and a subtropical climate.
But experts believe that environmental degradation due to climate change and human activity is allowing the rodents that carry the virus to breed in new areas, contributing to its spread.
“Increased human interaction with the wild environment, habitat destruction, the establishment of small-scale urbanization in rural areas, and the effects of climate change are contributing to the emergence of cases outside of historically endemic areas,” the ministry said.
Experts say that recent abnormal weather events such as droughts and torrential rains are also exacerbating this trend.
Rising temperatures will change the ecosystem, affecting the presence of long-tailed rats, the main carriers of the virus, in Argentina and Chile.
“These rodents may be better able to adapt to climate change, and as a result may drive the increase in cases that we are seeing,” explains Eduardo López, an infectious disease expert who served as an advisor to the Argentine government during the COVID-19 pandemic.
Roberto Debag, vice president of the Latin American Vaccine Society, said forest fires are increasing risk by forcing people and wildlife to move to new areas, but tourism trends are also having an impact.
“People who go to dangerous areas for tourism purposes are at very high risk if the undergrowth is not cleared,” Debug said.
The Ministry of Health announced that a health technical team will travel to Ushuaia, Argentina’s Tierra del Fuego region, to capture and analyze rodents in areas linked to the route through which the Dutch couple were believed to have contracted the virus.
But Juan Petrina, Fuego’s head of epidemiology, said the timeline “does not fit that they contracted the disease here,” citing airport and ship departure records that claim the couple were only in Tierra del Fuego from March 29 to April 1.
He also dismissed suggestions that the couple may have visited the Ushuaia landfill before boarding the ship, calling them “rumours”. “The National Ministry of Health has not been able to confirm that this is the case,” Petrina told a news conference in the southern Argentine city on Friday.
