Briefing Chat: Hantavirus — what this outbreak reveals about the disease

Introduction

0:00Hi, this is Elise Hu from TED Talks Daily, and this episode is brought to you by AmBetter Health. For many employers and brokers, group health insurance means unpredictable costs and plans that try to fit everyone but end up fitting no one. A model called ICRA is changing that. Employers set a fixed contribution. Employees pick the health plan that works for them, their family, their doctors, their budget. Predictable for the business, personal for the people. That's a better kind of coverage. Get coverage you control. Find out if an ICRA

0:33is right for you at AmBetterHealth.com.

0:38ACAST powers the world's best podcasts. Here's a show that we recommend.

0:46I'm Alexandra Fairweather, raised by one of the world's great creative geniuses, John Chamberlain, on his famous foam couches. Now I'm on the couch again with today's boldest creative minds for conversations that will spark your creativity and give you the courage to create something new. On the Couch launches May 19th with John Gray of Ghetto Gastro, whose food will make you rethink who belongs at the table. Season one, Daniel Arsham, Alexander Wang, Annabelle Seldorf, and more. Subscribe wherever you stream and follow along at John Chamberlain Estate.

1:25ACAST helps creators launch, grow, and monetize their podcasts everywhere. ACAST.com.

Hantavirus Outbreak

1:32Hi, Benjamin here. It's time once again for the Nature Briefing podcast, the Friday show where we talk about some of the latest science news. We've only got one story this week, and it's about the recent hantavirus outbreak on a cruise ship. We're looking at what phase the outbreak is in and what questions remain for researchers. Someone who's been writing about this is Nature's Rachel Fieldhouse, who joins me now down the line from Sydney, Australia. Rachel, how are you doing?

2:06I'm good. Thank you so much for having me on. Not at all. Right. Before we get into the specifics of the outbreak, I think it'd be worth giving folk a quick 101 on hantaviruses. Now this, it has to be said, double and dine, this is not COVID. So Rachel, tell me what it is. Hantavirus essentially is a family of viruses. So there are sort of two main types. You have like the old world and the new world. And the one that we're seeing at the moment is one of the new world species, and it's the Andes virus. That means

2:36that when it infects someone, it can go after their lungs, essentially filling them up with fluid. And it's a lot more fatal because of that than the old world, which goes after your kidneys and can cause longer term problems that are less acute and meaning that you can receive a bit more care and have a better chance of surviving. And folk tend to get these viruses by inhaling essentially rodent faeces or urine, right? Maybe they're disturbing it when they're walking through woodland, something like that. But the Andes species, as you mentioned there, which is central to this,

3:12is slightly different in that regard. Yes. So it can be spread through exposure to, it's essentially dust that contains particles from rat faeces, rat urine, rat saliva, but also the Andes virus is the only species that we know of that can spread human to human, though that has been rarely documented. You're right. The number of reported cases of the Andes virus are rare. And yet here we are now with this outbreak. And this obviously all centres on this Dutch flagged cruise ship, the NV Hondias, which set sail from the far south of Argentina towards Antarctica and then across

3:49the Atlantic Ocean. And that's a voyage that began on the 1st of April. What happened on that voyage? So Argentina has been having an outbreak of hedge virus for a while. And the current theory from experts at the WHO and a few other infectious disease bodies, they suspect that one of the passengers was somehow exposed to the Andes virus, became infected and then boarded the cruise ship. And then because of the nature of cruise ships, we've seen a lot of outbreaks in the past of COVID and gastro and now I think recently norovirus. This environment's really facilitated that human to

4:25human transmission. And that's what authorities think is going on here. Right. And at time of recording, then three passengers have died after travelling on the ship, two of whom were confirmed to have the virus. And in total, there have been 11 cases, eight of which have been confirmed according to the World Health Organisation. And what you've been writing about for nature, Rachel, is kind of what happens next? Because these are the numbers that we know of. And we're at the stage now where close to 150 passengers and crew have disembarked from the

4:59cruise ship or on their way home to wherever they are from where they'll quarantine. And what you've been writing about is that what these folk have to do very much varies depending on where they have returned to. Absolutely. So the general consensus seems to be that people should quarantine for at least 42 to 45 days. And infectious disease experts say that that's generally the time that'll take for the virus to incubate and then for symptoms to start appearing in particular countries. So in the UK, passengers who've returned via private plane to avoid exposure to more people have to first undergo

5:3372 hours of monitoring in hospital and then they can go into that isolation. In the US, they're all being taken to a particular medical centre in Omaha and then they can either choose to quarantine there or quarantine at home. And then there are also sort of specific rules and general advice for what they can do, like not leaving the house, alerting authorities when they want to travel and essentially just staying away from people until they hit that 42 to 45 day quarantine. And 42 to 45 days of self-isolation obviously is a very long time. Many of us have experienced

6:09shorter timeframes during the COVID pandemic, but perhaps this long time reflects what's not known about the action of the Andes virus and indeed of hantaviruses more generally. It does. I mean, part of it too is that this virus does just take a longer time to incubate compared to things like COVID and the flu. But also, again, we don't know a lot about how it spreads, which is, I think, why a lot of these authorities are being very cautious and limiting exposure because we don't know essentially why the Andes virus can spread person to person. We don't know

6:42what makes this particular species so special compared to others that do not have this kind of transmission. I mean, we don't even know how to really treat these viruses as well. There's a lot of really big unknowns about these viruses. And authorities, I would say, have stressed that risks are very, very low. You've spoken to a lot of infectious disease experts. What have they learned so far about the Andes virus? And what are the big questions that they've said to you that need to be answered, do you think? So, so far we know that generally transmission requires people to be in close contact for a

7:17decent amount of time. So, I mean, the European Centre for Disease Control, they say at least 15 minutes exposure within sort of a metre of an infectious person or, I guess, if you're on a plane sitting right next to someone or within a few rows. But what we don't know is, again, why this virus can spread. We don't know why it causes the particular symptoms that it does. And the running theory is that it could be spread by droplets, so respiratory droplets from an infected person. Some research has

7:49previously found viral particles in people's saliva, in like the nasopharyngeal samples, so like their nose and throat, and also from the fluid just secreted from their gums. So it might be there's this fluid respiratory transmission that's happening. But again, that's still sort of a theory. A lot more work needs to be done to show and confirm that this is what's happening. And one thing you mentioned in your article as well is that the virus has been sequenced already. And I think maybe there are echoes of the rapid sequencing of pathogens that we saw from a few years ago.

8:23Has that provided any information to researchers about what's going on here? Yes, it has. So it has shown that the virus is very similar to viral samples taken from previous outbreaks. It's stayed relatively unchanged, which I guess is an encouraging sign. So we're not really expecting hantavirus to behave any differently from it has in the past. By sequencing it, we know, for one, that it's the Andes virus, we know where it's come from. And that's fed into and helped support the theory of how these people actually got infected and led to this idea that potentially

8:57someone was infected before they even got onto the ship. Essentially, it really seems to be showing that this outbreak is very similar to what's happened in the past. And we're not really seeing any changes in how infectious or transmissible it is. And I think we've established there that numbers of people infected by these viruses, by the different species of these viruses each year, are fairly low, although the results can be serious, as we've seen. Have folk you've spoken to said that more attention will be paid to them now in case something like this were to happen again?

9:28It's not super clear what will be happening in terms of future funding. But up until now, it really has been a bit of a struggle for researchers in this area, partially because the viruses are so rare. We only see so many infections each year that developing vaccines or even treatments when people do get infected isn't really a big priority compared to some of the more, I guess, infectious diseases that are out there that can cause more severe symptoms. And that's also contributed to why we don't know a lot about these viruses too, because it could be hard to get the funding to do the

10:01research as well. And there are potentially even hundreds of other viruses that we've not seen yet that are just out there in rodents. But because they're not relevant to people and hunter viruses are generally rare and cause rare infections in people, there's just not financial incentives and financial resources that researchers can tap into to have a look and do this work. And finally, I mean, one has to imagine that a lot has been learnt from this outbreak that could potentially be useful further down the track.

10:32For sure. I mean, a lot of eyes have been on this outbreak, both among the general public and among researchers across antivirus fields and infectious disease. And really what one of my colleagues found when she was speaking to infectious disease researchers, one of them described this as a real-time experiment. And we're seeing essentially just what's going to happen next. And there are still things that remain to be seen in terms of what the virus will do, how it spreads to people, whether we'll see more people become infected. Well, let's call it, Rachel. Thank you so much. We'll put links to all of our articles

11:04in the show notes. But all that remains to be said is, Rachel Fieldhouse, thank you so much

Podcast Recommendations

11:07for joining me today. Thank you for having me on.

11:29A-Cast powers the world's best podcasts. Here's a show that we recommend. I'm Alexandra Fairweather, raised by one of the world's great creative geniuses,

12:03John Chamberlain, on his famous foam couches. Now I'm on the couch again with today's boldest creative minds for conversations that will spark your creativity and give you the courage to create something new. On the Couch launches May 19th with John Gray of Ghetto Gastro, whose food will make you rethink who belongs at the table. Season one, Daniel Arsham, Alexander Wang, Annabelle Seldorf, and more. Subscribe wherever you stream and follow along at John Chamberlain Estate.

12:37A-Cast helps creators launch, grow, and monetize their podcasts everywhere. A-Cast.com. A-Cast.com.