Hantavirus: the risks, the science and what you need to know

On May 2, the World Health Organization got an alarming report: People aboard a ship in the Atlantic Ocean were falling ill. The culprit is now confirmed as hantavirus, a pathogen that some rodents carry that can infect humans in rare, but often deadly, instances. Multiple passengers have died, and more people are showing symptoms. So, we’re talking to Emily Abdoler https://medschool.umich.edu/profile/5829/emily-abdoler, an infectious disease doctor at the University of Michigan, about the news – how common is hantavirus in humans, what are the consequences of getting it, and how can at-risk people protect themselves from it? If you found this episode interesting, listen to our episode on Rocky Mountain spotted fever. http://lnk.to/DyF2OA Interested in more science in the news? Email us your question at [email protected] mailto:[email protected]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave http://plus.npr.org/shortwave. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  This message comes from EasyCater, making it easy for organizations to order food for meetings and events from favorite restaurants, set up meal programs for their employees, and manage food spend all in one place at easycater.com.

• 0:15Emily Kwong?

  You're listening to Short Wave from NPR.

• 0:21Emily Kwong?

  On May 2, the World Health Organization got an alarming report that a ship in the South Atlantic was in trouble and multiple passengers aboard were severely sick with symptoms that seemed flu-like, but more serious. Some cases eventually evolved into a respiratory illness. And as of this recording Thursday afternoon at 4 o'clock Eastern, three people have died. And experts have confirmed at least some of those cases were caused by hantavirus. Some passengers have since been medically evacuated, but the rest are still on board, socially distancing. Jake Rosemarin is one of them and posted a video to social media.

• 1:00Speaker 02

  I am currently on board the MV Hades. And what's happening right now is very real for all of us here. We're not just a story. We're not just headlines. We're people, people with families, with lives, with people waiting for us at home.

• 1:23Speaker 03

  I can't even imagine the stress.

• 1:27Emily Kwong?

  Emily Abdallah is an infectious disease doctor at the University of Michigan. She's been following the news.

• 1:33Speaker 03

  I had never heard of hantavirus associated with a cruise ship before.

• 1:38Emily Kwong?

  Hantavirus infections are rare, but they can become very serious, depending on the strain of hantavirus, which is often transmitted from rodents to people. In the US, there were only around 900 confirmed cases of hantavirus between 1993 and 2023, the vast majority occurring in the Western US. 35% of those cases resulted in death. In medical school, Emily remembers being taught that people are usually exposed to hantavirus in rural places. The classic example is a remote cabin that's been locked up for the winter, now infested with mice.

• 2:13Speaker 03

  And it gets opened up for the spring and summer camping season, and humans are exposed to the droppings and the urine of the...

• 2:25Speaker 03

  Rodents and then come down with Haunta virus. And so the first thing that I really thought about is not knowing the timeline of the symptoms and how long folks had been on the ship. You know, is the ship infested with rodents?

• 2:42Emily Kwong?

  And as timeline details of this ship started to emerge, Emily had one big question.

• 2:49Speaker 03

  What species of virus is it? Because only one has been shown to potentially cause transmission in humans.

• 3:01Emily Kwong?

  Today on the show, Haunta virus and why it can be so deadly. Plus, how at risk you are at home and what you can do to protect yourself. I'm Emily Kwong and you're listening to Short Wave, the science podcast from NPR.

• 3:22Speaker 04

  Stay tuned for the following announcements and messages from our sponsors.

• 3:26Speaker 00

  This message comes from Avalara Aviator. Aviator is the agent hub for tax and compliance. If you've listened to enough podcasts, you know a confident answer isn't necessarily a correct one. Sources matter. The same goes for AI, tax, and compliance. Aviator is grounded in 20-plus years of Avalara tax intelligence and delivers source-backed audit-defensible outcomes with human oversight built in. Because the AI said so, won't pass an audit. Visit avalara.com/aviator. This message comes from Rosetta Stone, offering an alternative approach to language learning. Moving past rote memorization, the app guides users to intuitively think in a second language

• 4:07Speaker 00

  using images and contextual audio, mimicking how people acquire speech as children. The platform also includes advanced speech recognition technology that compares a learner's pronunciation directly with native speakers to refine accent precision. Learn more about their new Rosetta Stone Sapphire app at rosettastone.com.

• 4:27Speaker 00

  This message comes from EasyCater, the workplace food platform. EasyCater helps organizations order food from favorite restaurants, meet dietary needs, and stay on budget. With employee meal programs, flexible payment options, and 24/7 customer support, all on one platform. Learn more at easycater.com.

• 4:46Emily Kwong?

  I am here with Emily Appdollar to talk about what's happening on this ship and hantavirus. Emily, I understand hantavirus is from a group of viruses that come from rodents. How does hantavirus get passed on to humans?

• 5:00Speaker 03

  So typically, the rodent is infected. It's not very much affected by this virus, and it can carry the virus for a long time and get transmitted between the different rodents. And they excrete hantavirus particles in their urine, in their droppings, and in their saliva. So most cases are from humans getting exposed to the rodent droppings. So they'll be sweeping up the rodent droppings, and the virus particles get aerosolized. More rarely, it can come from rodent bites, but it's often being exposed to the droppings

• 5:45Speaker 03

  that get aerosolized, because they get dried out, and then they can more easily spread in the air.

• 5:50Emily Kwong?

  That's really tough, because people who are cleaning the rodent droppings are trying to do the right thing. They're trying to clear it. But you're saying the hantavirus can, if you're brushing with like a broom, it can fly up into the air and persist and get passed to people?

• 6:05Speaker 03

  Yes. If there are droppings in urine, you want to wear a mask when you're cleaning them, and as much as you can, wet them down, because when they aren't dried, they have less potential to aerosolize or go into the air. And we get this from inhaling the viral particles. In fact, when we look at cases in the Americas, from what I understand... A lot of the cases are in younger people of working age who are doing agricultural work. And so in some parts of the world, that's more men than than women who are in sheds and barns and sweeping things up.

• 6:45Emily Kwong?

  Okay, yeah. And there is one known strain of hantavirus that after someone is exposed to the bodily fluids of a rodent could spread from that person to other people. It's called the Andy's strain. And the WHO confirmed Wednesday, this is the strain that is aboard the ship. Were some of the early signs that experts were tracking?

• 7:05Speaker 03

  The WHO started releasing some information about the timing of symptom onset. And what's really interesting to me is that the first patient who fell ill had been traveling in South America, including in Argentina, before the ship left on April 1st. The first report of symptoms in that person was on the 6th of April. Now, most cases of hantavirus that I've heard about and what they report in the medical literature is that the incubation period, from the time you're exposed to the infectious disease until you manifest symptoms, is usually one to six to eight weeks for hantavirus.

• 7:50Speaker 03

  So this person got on the ship on the 1st.

• 7:52Emily Kwong?

  Yep.

• 7:53Speaker 03

  And had symptoms at least by the 6th. And that's really fast, but it's just at the razor's edge. And even a little sooner where one starts to wonder that this person was exposed before they got on the ship. And then this person unfortunately passed away shortly after the onset of their severe symptoms on the 11th of April. The next person, who as I understand was a very close contact, and I think if you look in some reports, this spouse of the person who passed away on the ship, the second person was first reported to have symptoms on April 24th.

• 8:35Speaker 03

  So that is several weeks after the onset of symptoms of the first person. And in my reading of these cases of human to human spread, it's often when the person is symptomatic that they have been shown to transmit to other people. So given that gap and that timeline, and then the others who have fallen ill, it's been, from what I understand, what's been reported, mostly around the 24th or the 28th of April. That's a several week jump from when the first person developed symptoms on the 6th of April.

• 9:14Emily Kwong?

  Okay.

• 9:15Speaker 03

  And I think you're seeing that possibility play out in how they're responding in terms of the public health interventions.

• 9:24Emily Kwong?

  They're doing like contact tracing and quarantining.

• 9:26Speaker 03

  Contact tracing, isolation, quarantining.

• 9:29Emily Kwong?

  Do we even know there will be more cases that emerge on the ship?

• 9:33Speaker 03

  So I think part of the question about more cases is not just the possibility of human to human spread, but I think it still remains a possibility that there was some exposure on the ship to animals or rodents.

• 9:51Emily Kwong?

  It could be both.

• 9:53Speaker 03

  Or to some commonplace folks stayed prior to getting on the ship. So in addition to contact tracing, the epidemiologists on the ground are figuring out when did people arrive in South America? Where were they before? Where did they travel? Where did they stay? Where were they situated on the ship? So I think, you know, it's a, it's a very nosey job, but it's a very important job because you need to ask people all kinds of questions to figure out what is more common in the people who ended up developing infection.

• 10:27Emily Kwong?

  So passengers on the ship, some have evacuated, but most are still aboard. And they have been advised to practice maximal physical distancing and remain in their cabins whenever possible to reduce transmission because this Andy strain of Hantavirus can progress into something really bad. We've seen that. So what can this strain of Hantavirus turn into?

• 10:47Speaker 03

  So Hantavirus pulmonary syndrome, HPS, that's predominantly in the Americas. And it's named to really let us know that it is predominantly impacting, when it becomes severe, the lungs and the heart.

• 11:02Speaker 03

  It starts out with those sorts of symptoms that we would just call like a flu-like illness, like fevers, myalgias, or muscle aches, joint aches, headache. And then it progresses to a severe respiratory illness, basically respiratory failure, or it can. And so if you look at it from a very basic science standpoint, how the infectious particle impacts the human body, it basically affects the capillaries and it causes them to become leaky. And the mechanisms for that aren't understood. But in the Americas, for severe disease, that leak is in the lungs.

• 11:47Emily Kwong?

  Wow. Okay, so with Hantavirus Pulmonary Syndrome, the worst outcome is if it turns into something in your lungs.

• 11:55Speaker 03

  The lungs and the heart.

• 11:56Emily Kwong?

  And the heart. And that's where you get these very high mortality rates, between 30 and 50%.

• 12:02Speaker 03

  Exactly. These are folks who need ventilators.

• 12:05Emily Kwong?

  Yep.

• 12:05Speaker 03

  And in some cases, they need ECMO.

• 12:08Emily Kwong?

  What's that?

• 12:09Speaker 03

  Sort of like a heart-lung bypass machine, extracorporeal membrane oxygenation. It's a way of bypassing both the heart and lungs to keep the blood oxygenated, to keep oxygen going to the body's tissues.

• 12:24Emily Kwong?

  Okay. Given that viruses know no borders.

• 12:28Speaker 03

  Yes.

• 12:28Emily Kwong?

  What do you think about the fact that earlier this year, the US officially pulled out of the WHO?

• 12:34Speaker 03

  I believe in public health. I have immense respect for public health officials and for those on-the-ground epidemiologists. And these folks are essential. They are essential to keeping us safe because infections will keep emerging and reemerging. And we need, it can't just be about... The physician with the patients in front of them. To protect the public, we need a broader response, which is public health. And we need to coordinate at a global level because infections are global. People travel. The vectors, you know, the animals and insects that carry these infections travel. They get on ships, they get on planes. People move around.

• 13:19Speaker 03

  And it has to be a global response and we have to work together to coordinate, especially in our very global world. So I, I think that working at that international level is critical. I think local public health is critical and everything in between.

• 13:42Emily Kwong?

  Dr. Emily Abdallah, thank you so much for talking to us.

• 13:46Speaker 03

  This was delightful to join you today and just thoughts with the people on the cruise ship and their families and with the public health officials helping to keep everyone safe.

• 14:06Emily Kwong?

  If you liked this episode, please share it with a friend. And while you're at it, follow Short Wave on the app you're listening to so you never miss an episode. This episode was produced by Berly McCoy and was edited by our showrunner Rebecca Ramirez. Tyler Jones checked the facts. Jimmy Keely was the audio engineer. I'm Emily Kwong. Thank you for listening to Short Wave, the science podcast from NPR.

• 14:36Speaker 04

  Stay tuned for the following announcements and messages from our sponsors.

• 14:41Speaker 00

  This message comes from Rosetta Stone, offering an alternative approach to language learning. Without relying on traditional memorization, the platform guides users to intuitively think in a second language. More information at rosettastone.com.

• 14:57Speaker 00

  This message comes from EasyCater, the workplace food platform. EasyCater helps organizations order food from favorite restaurants, meet dietary needs, and stay on budget. With employee meal programs, flexible payment options, and 24/7 customer support, all on one platform. Learn more at easycater.com.