Doubts grow over theory that bird-watchers’ trip to Argentine landfill sparked hantavirus outbreak

May 14, 2026

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Doubts grow over theory that bird-watchers’ trip to Argentine landfill sparked hantavirus outbreak

The hantavirus cruise outbreak may not have started in a garbage dump in Ushuaia, Argentina, after all

By Kate Wong edited by Clara Moskowitz

The municipal landfill in the city of Ushuaia in the Argentine province of Tierra del Fuego is a hub for bird-watchers.

CRISTIAN URRUTIA/AFP via Getty Images

Officials are investigating the origin of the outbreak of hantavirus on the MV Hondius cruise ship, which departed Argentina’s southernmost city, Ushuaia, last month. A Dutch married couple were the first to show symptoms of hantavirus. One theory that has gained prominence in media coverage holds that these individuals, who later died from the virus, picked it up while bird-watching at a landfill in Ushuaia before the cruise. But a closer look at the publicly available evidence reveals reasons not to put much stock in this scenario.

Here’s what we know so far. To date, there have been 11 reported cases of hantavirus from the cruise ship outbreak, and nine of them have been confirmed; of these cases, three people have died. Health authorities studying the cause of the outbreak are currently focused on those two Dutch citizens: a 70-year-old man, who developed symptoms on April 6 and died onboard the ship on April 11, and his 69-year-old wife, who developed symptoms on April 24 and died on April 26 in a clinic in Johannesburg, South Africa, while she was attempting to get home to the Netherlands. These victims are being referred to as the “index cases,” the first documented cases in an outbreak.

Hantavirus usually spreads from rodents to humans. People can contract it when they are exposed to infected rodents or their feces, urine or saliva. Infection typically occurs in poorly ventilated indoor spaces located in rural settings. The classic scenario is catching it while cleaning out a rodent-infested attic or cabin. In 2025 hantavirus made headlines after actor Gene Hackman and his wife Betsy Arakawa, a concert pianist, were found dead in their home in Santa Fe, N.M., and Arakawa was determined to have died from an illness caused by hantavirus.

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There are many kinds of hantaviruses. Scientists have identified the type responsible for the cruise outbreak as the Andes virus. It is found primarily in Argentina and Chile, where it is carried mainly by the long-tailed pygmy rice rat. The Andes virus is the only hantavirus known to spread between people.

The Dutch couple had been traveling in the Southern Cone of South America on a bird-watching trip starting late last November before they embarked on the cruise. According to the Ministry of Health of Argentina, the pair arrived in Argentina last November 27 and set off on a road trip, crossing into Chile on January 7 and then traveling to the province of Neuquén in western Argentina on January 31. Twelve days later, they visited Chile again before they returned to Argentina, where they drove from the province of Mendoza in the western central part of the country to the province of Misiones in the northeastern corner. On March 13 they crossed to Uruguay for two weeks, and then they went to Ushuaia on March 27. The cruise departed Ushuaia on April 1.

Researchers at Argentina’s Malbrán Institute will go to Ushuaia “to conduct rodent capture and analysis operations in areas linked to the movements of the [index] cases and to detect the possible presence of the virus in natural reservoirs,” according to a Spanish-language statement issued by Argentina’s Ministry of Health on May 6. That same day the Associated Press reported that two Argentine officials who were investigating the origins of the outbreak and spoke on the condition of anonymity said the government’s leading hypothesis was that the couple contracted the virus while bird-watching in Ushuaia before the cruise. As part of their birding tour, the officials told the AP, the couple had visited a landfill, where they may have been exposed to rodents.

When I heard about this theory, I was curious—and skeptical. I visited that landfill in Ushuaia on a bird-watching trip in February 2025 and didn’t immediately see why it would be conducive to hantavirus transmission based on what I knew about the disease.

Surrounded by the snow-capped mountains and majestic beech forests of Tierra del Fuego, the port city of Ushuaia serves as the main gateway to Antarctica. It hosted more than 150,000 cruise passengers in 2025. Its motto is “Fin del mundo, principio de todo,” which translates to “E