#14 – Hantavirus on a Cruise Ship: How Dangerous Is the Andes Virus?

00:00:06: So there's a lot of question marks and I think that is really the problem.

00:00:09: There are lots of unknowns, other outbreaks could be contained but then they were also in the countryside Argentina And now we're on the cruise ship right?

00:00:20: Again it makes complicated It just... The experience is lacking.

00:00:23: We don't have data.

00:00:33: Virological with Florian Kramer.

00:00:52: Welcome to this week episode of ViroLogical.

00:00:55: This was recorded on May tenth of twenty-twenty six in Vienna and today we're going to talk about Andes virus.

00:01:06: Before we start I have to apologize, i have some kind of respiratory upper respiratory infection as well so it might be a little bit harder to understand...I'm sure its not hunter virus.

00:01:19: this is some middle of the road respiratory virus.

00:01:22: that's I wanted to talk about.

00:01:28: Anders virus.

00:01:29: and Anders virus is a Hunter virus.

00:01:32: And so just going to start it little bit with some information about hunter viruses, they're named after the Hunter Anriva in Korea... ...and during the Korean War US soldiers became sick.

00:01:47: there was a disease that manifested as hemorrhagic fever with renal syndrome also issues with the kidneys.

00:01:58: And years later, the causative agent of that disease was identified.

00:02:04: and what became Hunter Virus.

00:02:08: So this virus there is Hantan Virus.

00:02:11: then as whole group of viruses.

00:02:14: many of them were discovered later on called Hunter Virus.

00:02:19: There are many of those you find globally most circulating rodents, rodent populations.

00:02:29: But they can also have other hosts like bats for example and some of them cause issues in humans.

00:02:35: typically people get infected when they interact with rodents or with rodent droppings, roden urine And that's how you typically get infected.

00:02:45: this with hunter viruses.

00:02:48: We'll get to that.

00:02:49: what is going on right now as well.

00:02:51: and why UNDES virus a very special hunter virus?

00:02:54: But typically, hunter viruses cause infections through contact with rodents.

00:03:01: Roughly we have two types of Hunter Viruses.

00:03:03: We have the Old World Hunter Virises that circulate in Asia In rodents and then Europe And cause disease there in humans as well.

00:03:12: Then you will have the New World Hunter viruses For example, Sinombra virus in the United States but they also are under this virus in South America.

00:03:22: How does the virus look like?

00:03:24: And this virus has a single-stranded RNA genome with negative polarity.

00:03:32: It's about, it has cold incapacity of around twelve thousand base pairs or about twelve thousand letters and its...it is a segmented genome similar to influenza.

00:03:42: on these various like all hunter viruses have three genomic segments.

00:03:50: So it's pretty simple.

00:03:51: S is small, M is medium and L is large.

00:03:55: s encodes for the nucleoprotein m encodes of the spike protein which in this case Is called GNGC.

00:04:03: so g for glycoproteins And then n for N terminus c for C terminus.

00:04:08: It was made as one protein Then cleaved into two parts.

00:04:12: The GNGC protein actually relatively complicated.

00:04:16: It has three transmembrane domains, its structure is complicated.

00:04:20: The structures become more clear.

00:04:22: there's nice structural biology work on it but there are still some open questions around them.

00:04:30: and then the L segment encodes for polymerase.

00:04:34: And so this virus.

00:04:35: relatively simple.

00:04:36: we have RNA genome inside these three segments.

00:04:41: genome is covered, the RNAs are covered by nucleoprotein.

00:04:45: There's polymerase associated with it.

00:04:48: then we have a lipid envelope and in this little bit of envelopes you can see the GNGC spike protein.

00:04:54: The virion is about eighty to one hundred sixty nanometers in diameter.

00:04:58: And for the new wild hunter viruses so synombra in United States but also UNDES It is known that the receptor is protocaterine-one which is brought on the cell surface talks onto the cells and then it's taken up into an endosome.

00:05:15: So these are this little vesicles that cells use to bring stuff inside, into the cell, in to the cytoplasm and then the virus starts to replicate their replicated genome.

00:05:51: And then new virus particles are produced.

00:05:55: somebody put on Twitter that you know, the virus goes through the nucleus.

00:05:59: it doesn't do that.

00:06:00: there's some RNA viruses did too dead but not hunter versus hunter versus replicating the cytoplasm.

00:06:07: okay where can we find on this virus?

00:06:09: It circulating in rodents in mostly Chile and Argentina.

00:06:16: The main host is oligoresomes, Longicotatus that's the longtail pygmy rice rat which a new world rat.

00:06:26: And these animals are infected.

00:06:30: They don't show any symptoms.

00:06:32: usually they basically spread their virus amongst themselves.

00:06:36: But you can also spread virus via the saliva via urine, via feces and then people can get in contact with these droppings.

00:06:48: It's also possible that there is transmission by a direct contact with this animals where bites or scratches.

00:06:55: but what very often happens is you know the droppings dry out.

00:07:01: Then through some activity dust is developed could be for example somebody using a broom to clean up.

00:07:09: and there are these droppings, they're dry.

00:07:12: that aerosolizes some of the material.

00:07:15: Then people inhale it then become infected.

00:07:19: This is actually true for many different hunter viruses And also for undisvirus.

00:07:24: most cases are caused by contact to rodents or their droppings.

00:07:31: We'll talk about human-to-human transmission a little bit later.

00:07:35: Undisviruses' only known hunter virus can do this.

00:07:39: But again, most cases acquire the infection through contact with these animals.

00:07:48: The people who are mostly at risk for infections or... People spend a lot of time outdoors and basically they have that long tail pygmy rice rats.

00:07:59: That includes hikers, people go camping, farmers, forest workers Minors, military personnel Zoologists who work with these animals.

00:08:13: and most infections actually happen in rural areas, which makes sense right?

00:08:18: Because that's where this animals are.

00:08:20: Okay so people get exposed.

00:08:22: then there is an incubation time That can last from one to eight weeks.

00:08:27: Typically it's one two six weeks.

00:08:29: And then the first phase of symptoms First phase of disease.

00:08:34: The lasts one or five days and that's influenza.

00:08:38: like People get fever, they're tired and lethargic.

00:08:43: They get muscle aches headache because anus virus replicates in the respiratory tract as well.

00:08:51: often there's respiratory symptoms including shortness of breath.

00:08:56: And then this moves into a second phase that is the cardiopulmonary phase.

00:09:02: so There are two words their cardiac pulmonary rates or heart and lung.

00:09:07: And so the virus starts to attack the lung, their heart and that's of course problematic.

00:09:13: One of the symptoms of death phase is people have irregular often very fast hard rate.

00:09:21: People develop cardiogenic shock So basically they are not able anymore to pump enough blood.

00:09:27: There also a pulmonary capillary leakage so liquid builds up in the lungs.

00:09:33: This can lead to respiratory failure very low blood pressure, shock basically.

00:09:40: And the name for this syndrome is Hunter-Virus pulmonary syndrome.

00:09:46: so HBS and This is typically what new world hunter versus do.

00:09:52: Xenombrae causes a very similar symptoms and this in contrast to old world hunter viruses like Hantaan.

00:10:02: they cause hemorrhagic fever with renal symptoms or HFRS.

00:10:07: So there you have involvement of the kidney during this second phase, the infection very often leads to death.

00:10:13: mortality rate or case fatality rate actually somewhere between twenty to forty percent and people who survive the infection usually also recover relatively slowly.

00:10:25: it can take months until a lung function is really back.

00:10:29: So not a nice disease to have.

00:10:30: It's relatively dangerous.

00:10:33: A little bit about the history, it was discovered in nineteen ninety-five In outbreaks of Argentina and in the same year as in Chile And because it happened in regions of the Andes mountains The virus is called Andes Virus.

00:10:49: Its also important to stress that its not super homogenous.

00:10:53: There are different kates, different versions Of the virus and the genotypes might actually also play a role in how likely it is that one of these strains infects humans or jumps from human to human.

00:11:06: I think we don't understand all of that, there's a lot of question marks with underswords but there's genetic diversity.

00:11:13: In nineteen ninety six There was an outbreak in the Rio Negro province of Argentina and they were first hints That the virus might jump from human-to-human.

00:11:27: There were also clusters in Argentina that suggested human-to-human transmission.

00:11:32: And then there was third incidence, in a Puyen in the Jabhat province where there is an outbreak In this village at Puyien with thirty four confirmed cases and eleven deaths.

00:11:48: And there it's clearly investigated That this law of Human to Human Transmission.

00:11:55: Actually, there are three people who were responsible for most of that outbreak from most of the infections and if one person infects a lot of people.

00:12:04: That's called super spreader.

00:12:06: We know this from SARS-CoV-one.

00:12:09: It was a big thing they're but hunter viruses specifically on this virus Might be able to do it as well.

00:12:18: I think overall their reproductive number in that outbreak They are not was about two, which means one infected person infects on average to more people.

00:12:29: And if you let that go of course the virus spreads right?

00:12:33: But countermeasures were implemented and that outbreak in EpiN was then efficiently stopped.

00:12:40: So because we have so little experience there's a lot of question marks about human-to-human transmission around this virus.

00:12:47: There is some data that suggests in the early phase of symptomatic disease, in order to spread the virus to another person.

00:12:58: But on the other side it cannot be excluded that somebody who is in an incubation period isn't symptomatic yet might also spread the coronavirus.

00:13:06: so there's question marks here.

00:13:08: The assumption is also you need relatively close contact but this wasn't a case for all human-to-human transmissions that have been recorded either.

00:13:22: And then in terms of mechanism, the assumption is that the virus can spread via respiratory droplets but potentially also as a liver.

00:13:32: the GI tract might be involved in some cases and we also know that the various cans spread from mothers to babies there's at least one case that I came across where it's not clear if it was through breast milk were already via the placenta, but that spread is possible too.

00:13:51: So there's a lot of question marks and I think that's really the problem.

00:13:55: There are lots of unknowns.

00:13:56: That not enough experience to say now okay you know this isn't going become big outbreak right?

00:14:05: The assumption everybody has other outbreaks could be contained But then they're also in country side Argentina And we on cruise ship.

00:14:16: And so, again that makes it complicated.

00:14:18: It's just the experience is lacking we don't have to data and there are a lot of question marks while... ...it seems like this situation under control.

00:14:29: There might be some more cases popping up but assumption is that will be handled then that outbreak or that these incidents will resolve in next few weeks.

00:14:42: We're not harvest insured right and with viruses.

00:14:45: There's always.

00:14:45: there's always surprises.

00:14:47: So that's why you we have to be careful with this.

00:14:51: And that brings me to the actual situation on the with this cruise ship, right?

00:14:56: This is the MV Hondius and this cruise ships left Usuaia This city in Fireland Del Fuego in Argentina.

00:15:09: they left down April first and April sixth.

00:15:14: one person got sick on board.

00:15:15: And it seems like this was a Dutch or an etologist who had already been traveling in South America for four months since the end of last November, at least that's what I read in the news... ...and maybe i should say before we get started here.. ..I have to stress this is tenth of May at night.

00:15:38: This is the current situation in terms of information that I have partially based on what the WHO said, partially based with news outlets.

00:15:49: So this situation is a little bit chaotic and it's evolving.

00:15:52: This episode will come out on Wednesday to Sunday so this situation might change.

00:15:57: there may be more info coming up.

00:16:00: keep that in mind with everything i'm saying.

00:16:03: take it with grain or salt.

00:16:05: but anyways this cruise ship left Argentina And on April sixth, somebody got sick.

00:16:12: As I said there is no suggestions that this was a Dutch ornithologist who had already been traveling extensively in the region and unfortunately he passed away.

00:16:24: on April eleventh The cruise continued.

00:16:30: they were out on the Atlantic from thirteenth to fifteenth of april.

00:16:35: They stopped at Tristan da Cunha.

00:16:38: So Tristan da Cunha is an island that belongs to the UK, but it's in the South Atlantic and It doesn't even have any airport.

00:16:46: So its very remote.

00:16:48: so keep that in mind.

00:16:50: And then the cruise ships sailed on and reached St Helena.

00:16:57: on April twenty-fourth St Helena another Island in the middle of the Atlantic.

00:17:05: The body of the deceased person was brought off the ship and... ...the wife of that first person who died also left the ship.

00:17:18: And it's already symptomatic.

00:17:21: Thirty more patients, or maybe there were twenty-nine, maybe they counted her as well... ...left the ship at St Helena then departed by blame so a lot people left them.

00:17:34: Then the ships sailed on And on April twenty seventh they docked at Asension, which is another island in the Atlantic.

00:17:45: Another person aboard was sick and that person was evacuated to Johannesburg in South Africa... ...and treated there an ICU.

00:17:55: I believe the person's still here in that ICU, and I believe it was the first person who tested positive for Huntervirus.

00:18:03: It might get it wrong but i think yeah... That person was tested positive!

00:18:07: And thats when news broke that there is potentially a situation with huntervirus.

00:18:12: On April twenty-eighth another person became symptomatic A person from Germany and that person died on May second.

00:18:25: that body was still on the boat when they arrived in Denneriva.

00:18:30: On May fourth, it was confirmed by the WHO this virus is actually under this virus and there were other possibilities right?

00:18:43: If you just know the infected individuals are positive for hunter-virus.

00:18:51: It could also be, and that was what the earlier report was.

00:18:55: Could also be for example a rodent infestation on the ship.

00:18:59: or if there are rats, rats carry soul antivirus which is actually an Asian antivirus And it could have caused some of these symptoms but turned out to be Anders virus.

00:19:10: That was crucial information because Anders virus is capable human-to-human transmission While soul virus cannot do this at least hasn't been reported.

00:19:20: But yeah, on May fourth we learned that this is indeed Andesvars.

00:19:25: Then from May third to may sixth the cruise ship anchored in Cape Verde and three more people were evacuated from the ship I believe.

00:19:38: person from the UK...I think it was the physician of the ship.

00:19:44: He had become sick.

00:19:46: he was evacuated to The Netherlands.

00:19:48: I believe there was also another person from the Netherlands that was evacuated.

00:19:53: They had some issues with that plane, i think they have to change planes in Gran Canaria.

00:19:58: but this person flew into the Netherlands.

00:20:01: and then a person from Germany who was finally evacuated to Germany to Düsseldorf And... There were more news that broke on May sixth.

00:20:14: In meantime Somebody had become symptomatic in Switzerland.

00:20:17: It was one of the people who left a ship on St Helena, One of these dirty people and hunter virus infection is actually confirmed to that person The person's in hospital in Switzerland.

00:20:31: I believe his wife also was with him at the ship And...the latest I heard it.

00:20:37: she didn't have any symptoms but She was self quarantining in Switzerland.

00:20:43: Okay!

00:20:45: May sixth, Hondius left Cape Verde but before they left three or four medical professionals boarded the ship.

00:20:55: There's conflicting reports about that and then came on board to help with the medical situation.

00:21:01: But this also included two epidemiologists who were there to find out what actually happened how a transmission could have worked, just basically get more information.

00:21:18: On May eighth the sequence from the Swiss patient was released online.

00:21:24: so the Swiss were working very quickly and again we already knew it was Andes virus but now there's a sequence.

00:21:33: you can actually look where that sequence falls within these different Andes-virus clades.

00:21:39: Yeah, it's closely related to what you would expect in this area.

00:21:44: But super nice job and super quick work by the investigators in Switzerland.

00:21:51: Okay initially I said that the ship stopped at Tristan da Cunha And today so May tenth There was news there might be one person on Tristan Da Cunhe who is symptomatic.

00:22:05: The problem is that they don't have a lot in terms of medical facilities, or an airport and it takes long time to go there by ship.

00:22:14: And so they needed medical supplies and medical personnel... ...and since people from the UK couldn't just go there and land their help They actually sent the sixteenth assault brigade.

00:22:31: they flew over over at least in the Acunia and then parachute it down with medical personnel, about three thousand kilograms of medical equipment including oxygen to support treatment.

00:22:47: I don't think there's a lot details on how this person is doing but potentially he was infected during interaction between people from that chip when it anchored here.

00:23:00: Okay and so we still have to go back to these thirty people that left the cruise ship in St Helena.

00:23:09: It seems they're all accounted for, so contact tracing was done... Maybe I should mention this?

00:23:14: The W Show is of course coordinating a lot of these efforts.

00:23:18: there's a lot energy put into finding all these contacts making sure that it's clear if they have symptoms or not, can be quarantined.

00:23:29: If there becomes symptomatic and so on... This is done basically in coordination between the WHO and all their countries involved with their national public health agencies And its actually nice to see how efficient this is.

00:23:44: So for these first thirty as far I know everybody has accounted For.

00:23:49: Yeah one of people who left Kurship In St Helena was of course the wife, in her first case.

00:23:57: And she also took a flight from St Helena to Johannesburg and I wanted go there through the Netherlands via KLM Flight five nine two But She already was symptomatic when left the cruise ship.

00:24:11: Her health deteriorated relatively quickly.

00:24:15: So she boarded that KLM flight to Amsterdam but then had deep word again because of her health and unfortunately she also died in South Africa.

00:24:29: but during the time on board which was relatively short KLM flight attendant took care of her.

00:24:36: so this flight attendant then also became symptomatic.

00:24:40: But, good news is that person tested negative for hunter-verse Ghanadilla and Anarif with a hundred forty seven individuals on board.

00:24:54: And as far I have seen in the news today, different nations started evacuation flights to bring their nationals home like into quarantine or medical monitoring which would make sense?

00:25:09: Again this situation is still under control that we might hear about few more cases in the next few days, but then it will hopefully calm down and Hopefully that outbreak will end relatively soon.

00:25:27: People are getting nervous about this a little bit And this is because of these open questions right?

00:25:32: The unclearity about human-to-human transmission.

00:25:37: In addition to setting on the cruise ship There's also issues.

00:25:44: we don't have any therapeutics to treat people with antivirus infections.

00:25:48: There's basically not much you can do, just treat the symptoms right?

00:25:52: there are some suggestions that ribovirin might be helpful but it may also not very effective and data is not really hard.

00:26:01: so we don' t have any antivirals or specific treatment which could give.

00:26:07: And thats tough because theres not much.

00:26:11: Historically for Hunter An plasma therapy was used, but again there is no hard data that suggests it worked well.

00:26:19: So Plasma Therapy basically means people who survived the infection were donating their plasma with neutralizing antibodies in them and then you would use this to treat fresh cases.

00:26:31: That's done back on the day of Hunter An infections during Korean War.

00:26:38: We don't know if that would work and it will also be hard to find enough people who had historically underswearers infections.

00:26:45: I missed mention of this initially, but there's about a hundred or two-hundred underswearer infections in Chile and Argentina every year.

00:26:54: And...I think these are good kind comparison on how problematic this is in terms human-to-human transmission.

00:27:04: There're described cases where human-to-human transmission happened, right?

00:27:10: Relatively few.

00:27:12: But then there's a sizable amount... not a lot but the sizable amounts of infections every year and most them are just sonotic infections.

00:27:20: were people get this virus from a rodent And don't give it to another human.

00:27:26: So I think we have keep that in mind also if you think about the situation There is so many unknowns That makes people uneasy Again, we don't have any therapeutics right?

00:27:39: And then the other point that makes me a little bit uneasy is vaccine development for Hunter viruses might not be so straightforward.

00:27:48: There's one type of vaccine that is available for hunter virus and it's against Hantan virus produced in Korea & China... ...and an inactivated vaccine where you grow the virus in cell culture and then harvest them purified, inactivated.

00:28:06: But the vaccine doesn't work very well And one of the reasons potentially why this is the case Is because The virus does not grow very well In cell culture.

00:28:13: It's really hard to cultivate it So you don't get enough yields during the vaccine production process so it might be really hard To make an inactivate a vaccine for this virus.

00:28:25: In addition that would be Really hard to grow these viruses.

00:28:30: biosafety level three or four conditions, probably biosafetely level four because of the large volumes needed to make a vaccine.

00:28:38: How do you do that technically?

00:28:41: Even if we do it at Biosafety Level Three there's not many facilities can handle this right.

00:28:47: If You Can grow enough of diversity doesn't grow well Enough.

00:28:51: In addition To That It might be hard Make Recombinant Protein Vaccines Just Because This GNGC Spike Is So Complex.

00:29:00: We now have a good idea about the structure, how it looks like but there's open questions too.

00:29:06: It is not so easy to make this soluble recombinant glycoprotein and might not be possible to do that right?

00:29:14: There has been DNA vaccines against hunter viruses.

00:29:17: they've developed including against the undies But their early clinical stage And its not clear if you could roll out for hundreds of millions people And it's also not key if would work, right?

00:29:31: Because this glycoprotein even if you use it as DNA vaccine.

00:29:34: It is hard to express and for ourselves make a lot of it.

00:29:40: And mRNA vaccines potentially be one the things that could work but there we don't know they do work.

00:29:48: They have been tested in animal models But no human data for under virus mRNA vaccine.

00:29:57: So there's a lot of question marks.

00:29:58: There is a lot research missing into hunter viruses.

00:30:02: It also one the few viruses where we don't have reverse genetic system that would allow us to manipulate the virus and get better understanding of certain molecular functions.

00:30:15: so again what I'm trying stress here, it has this situation under control.

00:30:23: It's very likely that this is not going to be a big issue in the long run.

00:30:30: There could be few more cases, but on the other side... But it's probably staying under control On the other sides.

00:30:39: there are these open questions right?

00:30:41: There're things we just don't know And theres research thats missing.

00:30:45: and I think if you learn something from this outbreak We have to take this virus serious and we probably have to do a hundred viruses in general series.

00:30:55: And probably should focus it little bit more on doing research of them, that's it for today for Virological as always if you any questions comments concerns.

00:31:07: just write an email at virologicalatpodcastvex.com.

00:31:12: If you want support the podcast You can do that unsteady.

00:31:15: Just one more note I'm probably going One more episode to follow up on the situation probably in two weeks.

00:31:25: If it calms down, if doesn't calm down... ...if other things happen might record something earlier.

00:31:31: but again I think there's an assumption that people have is that It is under control and with all this effort put into contact tracing And isolation quarantine measures This should not become a big problem.

00:31:45: Thanks for listening!

00:31:47: Until next time.

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