A cruise ship that left from Argentina on April 1 is currently at the center of an outbreak of hantavirus, a virus that most commonly spreads through rodent droppings and saliva. The virus causes flu-like symptoms and can lead to death.
There are eight confirmed or suspected cases aboard the MV Hondius cruise ship, including three deaths. The World Health Organization suspects hantavirus spread on board via human-to-human transmission, which is rare but can happen with certain strains of the disease; this includes a variant known as the Andes strain, which is the one that’s currently infecting passengers on the ship.
“There are multiple different types of hantavirus, and the only type that’s really ever been shown to possibly transmit human to human is Andes,” explained Kari Moore Debbink, a teaching professor in the department of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health in Baltimore.
Debbink said the Andes strain is found mostly in Chile and Argentina, which was the ship’s port of origin. The couple who died from hantavirus traveled through Argentina before boarding, according to reports.
Experts say the average person does not need to worry about hantavirus right now.
“This is a concerning outbreak,” said Jennifer Nuzzo, the director of the Pandemic Center at Brown University in Rhode Island. But “it’s not concerning for the general public.”
Dr. William Schaffner, a professor of preventive medicine in the department of health policy at Vanderbilt University Medical Center in Nashville, also noted that “at the moment, it is a confined, localized problem.” He added, “And, of course, we all have our fingers crossed that that’s how it will remain.”
Schaffner said he’s concerned for all of the people on the cruise ship and the caregivers on board, “but at the moment, I would not think that this is a matter of more general concern.”
“I think we’re focused on the people on that boat who are sick, those who are infected, and others who may have been exposed,” Schaffner added.
A Swiss man who traveled on the ship has tested positive for hantavirus in Switzerland, but the Swiss government said, “There is currently no risk to the Swiss public.”
The hantavirus outbreak isn’t currently like COVID.
If you’re wondering if this will become the “new COVID,” Debbink said she is not concerned about that happening at this time.
“First of all, in all of the cases … the transmission was only really between people that were in very close proximity, or had very, very intense interactions with each other,” Debbink explained.
The U.K. Health Security Agency notes that while it’s “unclear how human-to-human transmission of [the Andes hantavirus strain] occurs,” it’s suspected that “close contact with an infected person is necessary, and airborne transmission should be considered a possibility.”
That said, if this outbreak were spreading really easily, you’d likely see more sick people on board the ship by now, Debbink added. There have been eight confirmed or suspected cases, including three deaths, on the ship out of 147 passengers.
“It probably is a virus that, even if it does transmit human-to-human, it’s not very efficient,” Debbink said.
This is different from a coronavirus transmission, which worried some infectious disease experts as they learned more about it in the early weeks of the pandemic and saw how quickly and easily it spread.
The way hantavirus is transmitted, Nuzzo said, is “usually by exposure to contaminated droppings or urine.”
For this reason, hantavirus isn’t a top concern as of now, Nuzzo noted. “If you ask me what I’m most worried about at this point, it’s a new flu or a new coronavirus because we just have seen those viruses [cause pandemics],” Nuzzo said.
That said, experts stress the outbreak is concerning for public health as a whole.
“It is just a concerning outbreak because it is a virus doing something that looks bad — it’s killed three people, and it may have sickened twice that many, or even more than twice that many,” Nuzzo added.
This warrants attention from experts who study what viruses do “just to make sure that [the virus is] not starting to do new things,” she said, noting that there is currently no sign the disease is evolving from what experts already know about it.
“The fact that there’s human-to-human transmission isn’t necessarily the reason to sound the alarm bells, but it certainly is a reason to pay attention to this outbreak and to try to learn as much about the virus that’s affecting these passengers as quickly as possible,” Nuzzo added.
If you have plans to go on a cruise soon, you don’t have to be scared or cancel the trip right now, Debbink said.
“This is extremely rare,” she added. “This is the only situation that I’ve ever heard of hantavirus on a cruise ship, and it’s very unlikely that you are going to see this again. … I get people being really scared of something like this, but I do think that the risk to the average person is pretty much nonexistent, especially in the United States or Europe, or really anywhere outside of Argentina or Chile.”
Schaffner added, “Now, we always say when anything unusual happens: This is the best information we have right now, but as we get more information, stay tuned, because recommendations might change.”
Once again, that is unlikely in the case of hantavirus, but it’s better to have the latest information than to be left in the dark. If the general American public encounters the disease in the near future, it’s more likely to be from a strain that isn’t spread human-to-human. Hantavirus is most prevalent in the Southwest United States and is usually transmitted via rodent waste.
“I’m not changing my life for this,” Nuzzo said, yet it’s always important to be careful with rodent droppings, to wear gloves when cleaning up any droppings, and to practice good hand hygiene.
If you live in the Southwest and are doing anything that “stirs up dust or dirt,” Schaffner said, “see, first of all, if you can wet things down so it doesn’t create an aerosol.” This prevents the aerosolization of rodent droppings, which is a way hantavirus can spread, Debbink noted.
This situation also highlights the importance of public health funding and research, which is under threat.
Cases like the one we’re seeing with hantavirus now underscore the importance of public health infrastructure and relationships with public health groups across the world, such as the World Health Organization.
The United States withdrew from the World Health Organization earlier this year.
“There’s a reason why we try to build and maintain a well-equipped, responsive, agile and appropriately resourced public health system. Because we never know when viruses are going to do bad things, and it’s really helpful to have the infrastructure in place,” Nuzzo said.
Nuzzo added that the hantavirus outbreak on the MV Hondius cruise ship is more difficult to handle because the outbreak is happening in the ocean, between countries and jurisdictions.
“This is why it’s really important for countries to have strong partners with each other and to work collaboratively with the WHO because when something new arises, you want everybody on the same page, able to freely talk to each other and to share what is known,” Nuzzo said.
“Unfortunately, I think there was this effort after COVID to be like, ‘Oh, we’re done. We don’t have to think about diseases anymore. Let’s just dismantle all of the safety systems we worked really hard over decades to put into place,’” she continued. “When you do that, it makes it much harder to know what’s going on. And really, time and knowledge are some of our biggest tools to get ahead of these viral threats.”
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