Hantavirus: How Worried Should We Be?

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, explains 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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Dr. David Banach:
https://www.uconnhealth.org/providers/profiles/banach-david

UConn Health Infectious Diseases Division:
https://www.uconnhealth.org/infectious-diseases

UConn Health Orthopedics and Sports Medicine:
https://www.uconnhealth.org/orthopedics-sports-medicine

UConn Health:
https://www.uconnhealth.org

Grant support from Coverys:
www.coverys.com

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 li