An outbreak of an uncommon but not unheard-of illness is responsible for the deaths of at least three people who were on an international cruise ship. With the rest of the passengers and crew under observation in their home countries — including 18 Americans who went to a quarantine facility at the University of Nebraska — how worried do we need to be about hantavirus? Dr. David Banach, UConn Health infectious diseases physician and hospital epidemiologist, joins Dr. Anthony Alessi to explain what we're dealing with, the public health implications, and how, unlike COVID, the medical community at least has some history with this virus.
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Transcript
Dr. Alessi: Welcome to the Healthy Rounds Podcast, where we provide you with up-to-date and timely medical information from national and international leaders in their fields. This podcast is brought to you by UConn Health, with support from the Department of Orthopaedic Surgery and a grant from Coverys. It is not designed to direct your personal healthcare, and that should only be done with your physician.
I’m your host, Dr. Anthony Alessi, and it’s great to have as my guest today Dr. David Banach. Dr. Banach is an infectious disease specialist and he is head of the infection prevention program here at UConn Health. David, welcome to the show.
Dr. Banach: All right. Thank you.
Dr. Alessi: Let’s talk. I mean, there’s a lot of information out there about the hantavirus and how this all came about. Let’s go back and really address how this infection developed. What does it mean to our listeners?
Dr. Banach: Sure. So, kind of taking it back to the basics, hantavirus is a virus that we’ve known about now for many years, even maybe upwards of decades, that exists in the rodent population. So it’s primarily circulating among rodents, particularly in certain geographic areas. And then on certain situations it does infect humans, typically humans who are in close contact with rodents or rodent excrement. It causes what we call a zoonotic infection, where a virus that typically is present in animals moves into a human host. And in most situations, those are one-offs. Someone will have some sort of environmental exposure, could be in any part of the world, could be here in Connecticut, getting sick from this particular virus, and not pass it on to anyone else. But occasionally we do see it occur in clusters, and that’s what’s happened with this most recent situation on the cruise ship that returned and several individuals on that ship became sick and were eventually diagnosed with hantavirus.
I think in terms of the big picture, again, this does seem to have caused a bit of an outbreak on that ship. What it means for the larger public, I think we’re still kind of keeping an eye on it right now. I think the general feeling is that the risk for the general population is low, but I think it’s something that we’ll have to keep a close eye on in the coming weeks.
Dr. Alessi: What’s interesting when we talk about hantavirus, I’d never heard the term until Gene Hackman died of it, right? In the, in the past year, right, Gene Hackman and his wife die of hantavirus, and now we hear about hantavirus again. What’s the difference? He wasn’t in South America. Can you talk a little bit about why he’s dead and now these other people are dead.
Dr. Banach: Sure. I think the illness that his wife, I believe, contracted was the hantavirus, and that, there’s different strains of hantavirus. This particular strain, on the cruise ship, is the Andes virus. That’s like a type of hantavirus, if you will, that causes a specific illness. But there’s also, as I mentioned earlier, hantavirus that’s present in rodents throughout the world, and I think the situation with Gene Hackman’s wife, I think, was linked to some sort of environmental exposure to rodents that she was in contact with.
So it’s same virus, but a little bit different in terms of the way that it’s showing, in terms of individual cases versus, like, a cluster of infections like we’re seeing with this cruise ship.
Dr. Alessi: Now, when we talk about viral outbreaks, right, everybody immediately thinks of COVID. And there’s that fear of, are we going to be dealing with another pandemic? And obviously, with the hantavirus, the mortality is much higher than COVID. So can you talk a little bit about the differences and why this should not be similar to COVID?
Dr. Banach: Sure. “Viruses” is such a broad term. We think about our seasonal influenza viruses. COVID, of course, got so much attention over the last five years in the light of the pandemic. But then there’s other viruses. You remember Ebola was a big viral outbreak from a few years prior to the COVID pandemic, and they cause a wide range of illnesses. Hantavirus can cause quite severe illness. It causes a very severe cardiopulmonary symptom that can often lead to people needing ICU care and even succumbing to the virus.
In contrast to COVID, where the virus tends to be sort of uniformly a respiratory virus, so a little bit different in terms of, like, the clinical illness that they cause. In terms of the way they spread, also different. So COVID was different in a lot of ways. It was a virus that, first of all, we had never seen circulating in human populations.
As I mentioned, hantavirus is not new in that sense, so we’ve known about hantavirus, and we’ve seen individual infections. We’ve even seen clusters in the past. There was a large cluster around 2018, 2019 in South America that was well-studied and described. There’s actually a very notable New England Journal of Medicine publication on this hantavirus outbreak that came as COVID was starting to take off, so it went under the radar in that sense. But it was well-described, related to sort of a cluster of hantavirus infections, this particular type of hantavirus specifically. And so we understand a little bit more about how it’s transmitted. It doesn’t spread in the same way that COVID does in the sense that there’s no established sort of asymptomatic or pre-symptomatic spread.
Remember, that was a big challenge with COVID, that people could potentially be contagious before they showed signs of illness. But then on the other end of the spectrum, hantavirus does cause quite severe illness, and often has a much higher morbidity and mortality associated with it than COVID.
So, yeah, I think there’s differences. I think there’s some differences that make this less likely to spread in a larger fashion as COVID did. But I think it’s still early, that we have to kind of keep an eye on things, and what we’re going to be looking for in the coming weeks are any evidence of secondary transmission.
At this point, the people with infections have all been directly linked to the ship and the original cases of the two individuals who were first ill. But if we start to see additional spread, that would raise some concern that there may be a little bit more going on in terms of its ability to transmit to a the broader population.
Dr. Alessi: David, do antivirals help? I mean, these people who are being treated now who are symptomatic, and are they treating them with antivirals, or, what are they doing for these people?
Dr. Banach: Yeah, at this point, it’s really supportive care. As I mentioned, these patients can develop really severe cardiopulmonary illness, requiring pretty intense supportive care at times.
There’s a wide spectrum of illness. Some individuals may recover with sort of minimal support, but some do become quite sick. So it’s really supportive care at this point. We don’t have an established antiviral per se, and there’s no vaccine available for hantavirus at this point, and that’s largely because these infections, although we’ve known about them for many decades, are quite infrequent.
I think, and the CDC I think, they reported that there’ve been something like 800 cases described since 1990 of hantavirus in the US. So it’s been circulating, but very sporadically. So there hasn’t been kind of a need for sort of a wide-scale public health intervention. But, I think we’ll have to keep an eye on this particular outbreak and see how things unfold.
Dr. Alessi: Do we need to do anything here in Connecticut?
Dr. Banach: I think at this point, the most important thing for people here in Connecticut is to kind of listen to what’s happening. There doesn’t seem to be a direct risk to people here in Connecticut from this infection, but listen to what you’re hearing on the news. See what’s being reported by the public health authorities and, how the situation evolves.
My optimistic hope is that this will be very limited, and the outbreak will subside with now that the appropriate measures are being taken to try to quarantine people who are exposed and prevent spread, but we’ll have to keep an eye on things.
Dr. Alessi: When you say listen, that raises a flag because we don’t know who to listen to anymore, right? We’ve had some issues with scientists leaving the CDC. Do you listen to the WHO? I- if you go on the internet, we’re all going to be dying in the next week from hantavirus. So who do you listen to? I mean, who should, who do you consider the reliable source here for our listeners?
Dr. Banach: I think that is a real challenge for the public to really understand how to get accurate information. With this particular situation, the World Health Organization seems to be the most tied in. Remember, this is an outbreak that started outside the U.S. The initial cases were detected, and those patients are being taken care of in various countries, including, I think, countries in South Africa and other parts of the world. So the WHO is really leading this effort, and they’re keeping updated stats and updated reports on how things are unfolding.
So I think that they’re the most attuned to what’s going on, and I would have confidence in what they’re reporting out. But now the news is taking hold of this story, sometimes for better, sometimes for worse. And take the information that you’re getting as it’s coming to you, but, think about, I think the CDC has been reporting updates on the hantavirus situation based on information they’re getting from WHO and other international sources. But I think those are the kinds of voices that we can listen to at the moment and learn as much as we can.
Dr. Alessi: I want to talk to you a little bit about the incubation and the isolation period. In European countries, most notably Spain and France, people who were exposed on the ship are isolated for 42 days, and they feel that that’s the safest thing to do. Here in the United States, we’re kind of letting people decide for themselves how much they need to isolate, which always shakes me up a little bit. Can you talk about why we’ve taken this relaxed view of isolation as opposed to other countries?
Dr. Banach: I think it is varied in terms of the way that isolation is handled. So the incubation period, like you mentioned, is up to 40 days, so that means patients may not become sick for that period of time. And different approaches are taken to how patients are going to be monitored who were potentially exposed, and different countries are taking different approaches.
I think here in the U.S. we have a few different ways that we’ve handled it. I know there are, the highest risk individuals, I think, are being monitored very closely. I think several people, especially those who are showing any signs and symptoms, are being monitored in, like, a biocontainment unit in Nebraska, I believe.
But other lower-risk exposed individuals can be monitored by public health authorities in a less invasive kind of way. And we’ve seen this also with, thinking about individuals who returned from Africa after taking care of Ebola patients, they were still monitored by public health authorities. For instance, the state or local health department would be checking on them frequently after they returned. They weren’t necessarily confined to their homes. They were allowed sort of limited public exposure as long as they were checking in with the appropriate public health authorities. So I think we, we sort of triage exposed individuals, the highest-risk individuals being monitored the most intensely.
I mean, certainly anyone who has symptoms gets really the most intense monitoring. But we sort of triage based on the level of exposure and ensure that we have monitoring that’s appropriate. But I think the different countries are taking different approaches, and I think we have to rely on our public health authorities here in the United States to monitor exposed individuals appropriately.
Dr. Alessi: David, thank you. Thank you for your time today. Thank you for jumping on this on short notice. You’re always our trusted resource when we have questions around here. So thanks again.
Dr. Banach: Thanks, thanks for having me on, and happy to give any updates as needed.
Dr. Alessi: Thanks again. If you have any questions or ideas for future programs, you can reach out to me at healthyrounds@uchc.edu.
Jennifer Walker is the executive producer for the Healthy Rounds Podcast. Christ DeFrancesco is our studio producer. Until next time, this is Dr. Anthony Alessi. Please stay healthy.
