On Friday, the Ontario County public health department reported that a suspected hantavirus case involved a high school student in upstate New York. Local public health officials said there was no risk to students, teachers or the general public and no connection to the Andes virus outbreak tied to a cruise ship that departed Argentina last month.
This case is believed to involve the strain of hantavirus responsible for most cases in the United States, one that is not known to spread person to person. Hantavirus is a rodent-borne illness rarely found in New York, where only six cases have ever been reported.
Three New Yorkers quarantined after the Andes virus outbreak
By contrast, the cruise ship cluster involved a South American strain capable of human-to-human transmission.
Three New Yorkers who were passengers on the cruise ship at the center of the Andes virus outbreak are in their second week of monitoring at the air base in Nebraska where passengers were taken on May 11 for a 42-day quarantine. One is a New York City resident; the other two live in Orange and Westchester counties, according to the New York State Department of Health.
“At this point, it is important to emphasize that there is no immediate risk to the public,” state Health Commissioner Dr. James McDonald said in a statement.
‘Extremely rare’ and ‘low risk’ to New Yorkers
Local infectious disease specialists echoed state health officials in saying the Andes virus poses little risk for New Yorkers. Among them is Dr. Luis Marcos, an infectious disease physician at Stony Brook Medicine who treated one of the only documented hantavirus cases ever reported on Long Island, in 2017.
“It is very unlikely the virus will go into the community — chances are almost 0%, because they are being monitored,” he said.
Public health measures like isolation and contact tracing are generally effective at containing the spread of outbreaks linked to the Andes virus in South America, he said. There is no vaccine for hantavirus.
“If the [World Health Organization] had never alerted the world and the contacts from these crews had left without any tracing, without quarantine, without anything, then I would be worried,” Dr. Marcos said.
The Andes virus situation
Previous outbreaks involving suspected person-to-person transmission of the Andes virus were documented in Chile in 1997, 2004 and 2014, and in Argentina in 1996 and 2018.
In 2025, Argentina had the highest number of confirmed cases in the Americas of hantavirus pulmonary syndrome, or HPS, a severe and potentially deadly respiratory disease caused by exposure to infected rodents.
Argentina’s hantavirus cases nearly doubled to 101 cases in 2025 from 57 cases the year before. The trend makes Marcos wary of travel even as he acknowledged that overall case numbers remain relatively low.
“When you ask me, if I’d go to Argentina, I’d be very, very, very careful in these remote rural areas, because the hantavirus is ongoing,” he said.
Some studies suggest global warming may be shifting the rodent host population for the Andes virus, particularly the colilargo, or long-tailed pygmy rice rat. Extreme weather changes — very rainy periods and very dry periods — can cause rapid growth in rodent populations. There has also been more contact between humans and nature through more development in rural areas, tourism and outdoor activities, such as during the bird-watching expedition linked to the recent cruise ship cases.
At the same time, better diagnostic techniques mean that cases that may have gone unidentified before are now being easily detected in the lab.
Brazil, Bolivia, Panama, Paraguay, Uruguay and the United States also had confirmed HPS cases documented last year. In the United States, however, HPS is caused by the Sin Nombre virus, which is spread by deer mice. People can become infected by inhaling airborne particles from rodent urine, droppings or saliva that contain the virus. Unlike the Andes virus strain, Sin Nombre virus is not known to spread from person to person. In the U.S., New York and other states in the Northeast have some of the fewest documented cases in history.
Keep doing what you’re doing — with precautions
For the average New Yorker, Marcos said, “I would recommend to continue doing daily activities, to enjoy the spring and the summer, to do what they have been doing so far.”
Still, doctors say people spending time outdoors should take basic precautions around rodents and rodent droppings. As with other infectious diseases, the symptoms can be flu-like, including fever, fatigue and muscle pain. But doctors typically only suspect hantavirus if a patient recently had close contact with rodents or their bodily fluids, known infected individuals or contaminated campsites.
Experts recommend campers steer clear of trash-filled campsites, avoid sweeping contaminated areas and use gloves when handling potentially contaminated soil or food.
Even so, Marcos said hantavirus remains far less concerning in the United States than more common infectious threats.
“I’m not worried about hantavirus — worry about measles,” Dr. Marcos said. “We’ve had a vaccine available for almost half a century. I’m more concerned about that.”
