An opportunity to study something new in the southernmost reach of Argentina
Two weeks after the cruise ship outbreak, teams deploy traps and collect samples from natural areas including Tierra del Fuego National Park and four other sites. Scientists seek the long-tailed mouse (Oligoryzomys longicaudatus), the known reservoir for Andes South hantavirus in Patagonian forests.
- Two weeks after MV Hondius outbreak, teams deploy traps across five Ushuaia locations
- Long-tailed mouse (Oligoryzomys longicaudatus) is the only known natural reservoir for Andes South hantavirus in the region
- No hantavirus cases have ever been detected in Tierra del Fuego province
- Andes South hantavirus documented circulation reaches only as far south as Chubut province, 1,500+ km north
- Field laboratory established at Estancia Túnel, accessible only by foot after one hour of walking
Argentine health authorities launch environmental sampling and rodent capture operations across five Ushuaia locations to trace the origin of a hantavirus outbreak that affected cruise ship MV Hondius passengers.
Two weeks after a hantavirus outbreak aboard the cruise ship MV Hondius sent an international health alert rippling outward from the port of Ushuaia, Argentine authorities finally began the work of tracing where the virus came from. Starting this week, teams fanned out across five locations in the natural areas surrounding the city—placing traps, collecting environmental samples, and hunting for the animal that likely carried the disease into human hands.
The operation brings together the Tierra del Fuego provincial health directorate with a specialized team from Anlis-Malbrán, the national laboratory institute, arriving to set up what amounts to a mobile field laboratory. Three biologists from the National Institute of Infectious Diseases will deploy traps across designated sectors chosen for their ecological and epidemiological characteristics—places where the reservoir animals live, and where few people venture. The sites include Tierra del Fuego National Park, Playa Larga, Baliza Escarpados, the grounds around Camping Olivia, and Estancia Túnel, along with the open-air landfill that has drawn particular scrutiny. The landfill connection traces back to a Dutch couple of birdwatchers who appear to have been the index case—the first to fall ill—and who, like other bird enthusiasts in the region, may have visited the dump's surroundings.
The hunt centers on one animal: the long-tailed mouse, scientifically known as Oligoryzomys longicaudatus. This small rodent is the only known natural reservoir for Andes South hantavirus in the Patagonian forests of southern Argentina. Once infected, these mice shed viral particles into the environment for extended periods, making them efficient vectors. Other rodent species present in the region—the olivaceous mouse and the long-haired mouse—can become infected and transmit the disease, but their immune systems quickly develop antibodies that clear the virus, preventing sustained environmental contamination. The distinction matters: it means that if Andes South hantavirus is present in Tierra del Fuego, it almost certainly arrived via the long-tailed mouse.
What makes this investigation unusual is what researchers have not found. The long-tailed mouse ranges from Neuquén province all the way south to Tierra del Fuego. But Andes South hantavirus, according to documented cases, circulates only as far south as Chubut province—roughly 1,500 kilometers north. No cases of hantavirus have ever been detected in Tierra del Fuego itself, and the province has no record of locally acquired infections. Scientists from the Austral Center for Scientific Research, part of Argentina's national research council, have maintained the most complete historical record of the long-tailed mouse population here since the 1990s. They now use environmental DNA extracted from river water samples to monitor rodent populations across the island, from Ushuaia to Río Grande, a method far more efficient than traditional trapping. Their latest findings, about to be published internationally, map the genetic diversity of the region's rodent fauna with precision.
At Estancia Túnel, accessible only by foot after more than an hour of walking, the team will establish a field laboratory by Friday. There, captured rodents will be identified, and blood and tissue samples will be collected, sealed in biohazard containers, and stored at minus 80 degrees Celsius in local freezers before transport to the national reference laboratory in Buenos Aires. Technicians will test the samples for antibodies against hantavirus. If antibodies are found, further analysis will determine which viral variant is present. The traps themselves are simple: baited with food attractive to nocturnal rodents, they are set during the day and checked at night, when these animals are most active.
Authorities and local researchers agree that finding the virus in Tierra del Fuego would be surprising, perhaps unlikely. But the investigation proceeds anyway—not as a desperate search for a threat that may not exist, but as what specialists describe as an opportunity. If Andes South hantavirus has somehow established itself in the southernmost reaches of Argentina, understanding how and where it arrived matters for public health. And if it has not, the negative result will be its own kind of answer, one that helps explain how a Dutch couple of birdwatchers, visiting a remote corner of the world, came home carrying a virus that should not have been there.
Citações Notáveis
The selection of these sites responds to environmental characteristics and the habits of rodent species of health interest, mainly the long-tailed mouse and two species of Abrothrix mice, linked to hantavirus transmission in natural environments of southern Argentina.— Anlis-Malbrán institute
A Conversa do Hearth Outra perspectiva sobre a história
Why did it take two weeks to start looking for the source? That seems like a long time when people were already sick.
The outbreak happened aboard a ship that had already left port. Once passengers scattered internationally, the focus shifted to tracking them down and treating them. The investigation into where the virus came from—that's a different kind of work. It requires coordination between provincial and national labs, and it takes time to plan where to look.
So they're looking for a mouse. How do they know it's a mouse and not something else?
Because of what we know about how this particular virus spreads. Andes South hantavirus has one main animal reservoir in this region—the long-tailed mouse. Other rodents can carry it briefly, but they clear it from their bodies. The mouse is the only one that holds onto it long-term, shedding it into the environment where people might encounter it.
And they've never found this virus in Tierra del Fuego before?
Never. The virus circulates in Patagonia, but only as far south as Chubut. Tierra del Fuego has no documented cases of anyone catching it locally. So finding it here would be genuinely surprising—which is partly why the researchers are treating this as an opportunity to understand something new.
What happens if they find the virus in the mice?
Then they'll know it's established itself in the island's rodent population, which changes the public health picture. If they don't find it, that raises its own questions about how those birdwatchers were exposed in the first place.
The birdwatchers visited a landfill?
That's one theory. Birdwatchers in the region often visit areas around the open-air dump because certain bird species congregate there. If the couple went there, they may have had contact with infected rodents or contaminated surfaces. It's one of five sites the teams are investigating.