Argentina under global scrutiny over hantavirus as cruise ship contacts traced

Three decades after the first recorded human-to-human transmission in Patagonia, Argentina is again in the spotlight after three people died from hantavirus aboard the Dutch cruise ship MV Hondius, which sailed from Argentina to Cape Verde. Scientists warn that global climate change could increase worldwide exposure to the virus.

An outbreak in rural communities in Patagonia 30 years ago allowed scientists to document human-to-human transmission of hantavirus for the first time, which had previously only been known through contact with rodents. Nearly a decade earlier, another outbreak in Patagonia provided detailed evidence of person-to-person infection when a 68-year-old rural worker who caught the disease attended a birthday party in a small village, leading to 11 deaths.

Although the mode of infection for MV Hondius passengers has not been confirmed, the World Health Organization (WHO) has hypothesized that transmission occurred before boarding, placing Argentina under global surveillance. The WHO has ruled out the possibility of an epidemic. Tests on surviving passengers confirmed they carried the Andes strain, the only strain known to transmit from person to person, primarily found in Argentina and Chile.

However, Argentine scientists who have studied the virus for decades argue that despite a slight recent uptick in cases, the country is not facing anything new or significantly different from previous decades. “Argentina is accustomed to dealing with hantavirus,” said Dr. Roberto Debbag, an infectious disease specialist and Vice President of the Latin American Vaccine Association. He noted that the country has required mandatory reporting of hantavirus infections since 1996. “Since then, there have always been cases and outbreaks … but nothing has really changed.”

Since July last year, Argentina has recorded 101 hantavirus cases with 32 deaths; in previous epidemiological seasons from July to June, the numbers were lower, such as 64 cases and 14 deaths in 2024-2025, and 82 cases with 13 deaths in 2023-2024. Dr. Raúl González Ittig, a biologist and professor at the National University of Córdoba, attributes the increase to rodent behavior, driven by a significant drought in 2023-2024 followed by increased rainfall, leading to abundant vegetation and more food for animals. “Global climate change is changing everything, and that could also lead to hantavirus cases appearing in places where they have never been before,” he said.

Despite the increase, Argentina remains within its historical annual average of about 100 cases — far lower than China and South Korea, which report thousands of cases annually, according to the WHO. Most of the 100,000 hantavirus cases each year occur in Asia and Europe, but the key difference lies in severity due to different strains: while the mortality rate in those regions is up to 15%, in the Americas it can reach 50%.

Nevertheless, the WHO says the hantavirus risk to the general population is “extremely low,” noting that human-to-human transmission does not occur easily. Argentina still has the highest number of cases in Latin America, which scientists attribute to the climate crisis and ecological imbalances such as the loss of natural predators.

To identify where contamination may have occurred on the MV Hondius, Argentina's Health Ministry plans to trap rodents for analysis along the route of the Dutch couple who first showed symptoms. They had been in Argentina since 27 November, taking multiple car trips including to Chile and Uruguay, before boarding the ship on 1 April from the port of Ushuaia. The Health Ministry stressed that “it has not been confirmed that the infection occurred in Argentina” and noted that the province of Tierra del Fuego, where the ship departed, has had no hantavirus cases in 30 years.

On 7 May, WHO Director-General Tedros Adhanom Ghebreyesus said Argentina should “reconsider” President Javier Milei's decision to withdraw from the organization, following the lead of his ally Donald Trump. “Viruses don't care about our politics and they don't care about our borders,” Ghebreyesus said. “Solidarity is our best immunity.”

For Ittig, Milei's decision to leave the WHO is another facet of the problem caused by deep spending cuts in science, education, and health under the “chainsaw” policy, which could affect efforts to combat hantavirus. “The experience and knowledge to solve hantavirus exist, and Argentina has them,” he said. “The problem is that investment is needed — and that is not happening now.”