Mary Jo Trepka is an infectious disease epidemiologist and a professor in the Robert Stempel College of Public Health & Social Work. She answers questions here that have arisen among the public following a recent outbreak of hantavirus on a cruise ship that departed from Ushuaia, Argentina, in early April for a tour of Antarctica and remote Atlantic islands. To date, three people have died, and at least five others have been sickened.
It is understood that health authorities from multiple countries, including Argentina, are investigating and working with the World Health Organization.
What can you tell us about this virus, the hantavirus, which most of us have never heard of before?
There are many different types of hantaviruses. Some, like those in in Europe and Asia, tend to cause problems with the kidneys and bleeding. And then there are strains within the Americas, North and South America, and they are more likely to cause problems with the lungs, pulmonary syndrome. So, that's what these people on the ship experienced.
One of the strains within the Americas is called the Andes strain, and the World Health Organization is confirming that this outbreak's strain is the Andes strain. Now, that makes a lot of sense because the first two people recognized as having it had been traveling in Argentina, where the Andes strain is known to exist.
How is it contracted, and how does it spread?
Now this is a very rare disease. With most of the hantaviruses in North and South America, including the Andes strain, people are exposed through rodents. So rodent droppings, rodent urine. That's the normal way that people are exposed. But the Andes virus also has been known to be transmitted from person to person.
In this case, we don't know how the first person got it. From what the World Health Organization wrote and based on when the first person got sick, it's most likely that this person was exposed during travels in Argentina before getting on the ship. The second person who was traveling with the first person in Argentina could have been exposed the same way or by person-to-person transmission as the second person was a close contact. The subsequent people who became ill apparently were exposed by person-to-person transmission on the ship.
Some people have worried that they should cancel planned cruises in light of this news. What would you suggest?
I think this is a very special situation that occurred. A person was traveling and exposed to this relatively rare virus, most likely through rodents, and then they just happened to bring it onto the ship. This Andes virus is not a new virus, and there have been previous outbreaks of Andes virus with documented person-to-person transmission. It's a very sad and terrible situation, but based on current information, this is not a new pathogen like COVID-19 was. Nor is this a new mode of spread.
What is notable is that this occurred on a cruise ship. However, that does not necessarily mean that people are going to be exposed to the Andes virus on other cruise ships because someone has to bring the virus on board.
The virus is rare. To put it in context, PAHO [The Pan American Health Organization, a specialized agency of the United Nations] found that in 2025 eight countries reported hantavirus pulmonary syndrome, a total of 229 cases and 59 deaths. So, 26% died.
The cases were in Argentina, Brazil, Bolivia, Chile, Panama, Paraguay, the United States, and Uruguay. The Andes strain of hantavirus is also not normally present in the United States, and the strains of hantavirus that exist in the US are rare and tend to occur in the western part of the United States. Based on publicly available Florida Department of Health data, there was not a single case of hantavirus in Florida during the 32-year period from 1992 to 2024. Based on the current information, it is not necessary to cancel a cruise.
However, by its very nature, cruise travel brings people into much more close contact with a lot of people than they would normally have. That lends itself to more transmission of respiratory illnesses and diarrheal illnesses. So that we have a new outbreak on a cruise ship of a respiratory infection that has been known to be transmitted person to person is not so surprising.
Therefore, when you are planning to go on a cruise, it is important to make sure that your immunizations such as measles, influenza and COVID-19 are up to date, that you wash your hands regularly or use hand sanitizer, consider wearing a mask if an area is really crowded, and if you have a weak immune system, discuss your trip with your health care provider ahead of time.
What are some of the symptoms?
People get fever and headache, muscle aches. They can also have some gastrointestinal symptoms like abdominal pain, nausea or vomiting. And then with this pulmonary syndrome, they can get cough, shortness of breath. When it gets to the lungs, it's very severe and you need intensive care immediately.
I've read it has a high fatality rate. Could those who have died been saved in a different situation?
There is no specific treatment for Hantavirus infections except for intensive supportive care. It is possible that if those who died had been obtained intensive care very early, their outcomes may have been better but that cannot be assured. The disease progresses very quickly.
Based on the information released by the WHO to date, the risk from this outbreak to the public is very low. However, it is very likely that we will learn something new from the ongoing investigations of this outbreak. We may learn something new about the virus, its transmission or about specific environmental conditions on the ship that facilitated transmission. If so, that information may help prevent an outbreak like this in the future.
