Hantavirus: What you need to know

S1: Welcome in San Diego. It's Jade Hindman on today's show. Now that passengers from the cruise ship where the hantavirus spread disembarked , several passengers from California are being monitored. Is there an outbreak risk ? Sharp health care epidemiologist Stephen Munday joins me with answers. This is KPBS Midday Edition. Connecting our communities through conversation. So right now , health officials around the world are monitoring people who left a cruise ship hit with an outbreak of hantavirus. Earlier today , 18 American passengers returned to the U.S. one tested positive for hantavirus here to break down. The latest is Doctor Stephen Munday. He's an epidemiologist with Sharp Health Care. Welcome , doctor Monday. Hello.

S2: Hello. Thank you for inviting me. And nice to be here.

S1: Great to have you here in studio. So at least nine cases have been reported and that includes three deaths.

S2: Obviously the latest numbers I saw said that there are now ten confirmed or suspected cases , and some of those have just come over the last couple of days. Hmm.

S1: Hmm.

S2: And because this one can be spread person to person , that is why there's been a lot of concern. The original cases were people who had been traveling through South America before they boarded the ship , and unfortunately , they didn't develop symptoms and become ill until after they were on the ship. And the ship had departed from the port.

S1: So you said this virus can spread person to person.

S2: There are a number of different species and they have a couple of different ways they present. The ones that are found more commonly in Europe and Asia tend to present more with kidney issues , and perhaps with what we would call a hemorrhagic fever , where they have bleeding issues. But the ones that are found in the New World , so in North and South America , tend to present with what they call pulmonary or cardiopulmonary syndrome , so that the people present , typically with shortness of breath , which can become very severe and lead to respiratory failure and ultimately to death. Hmm.

S1: Hmm. And it's it's. Well , I mean , I want to know.

S2: All of the other hantavirus are in specific species of rodents , and only if you have exposure to the rodent or the excrement from the rodent and get exposed to that. Can you develop a hantavirus syndrome ? In this case , there is a rodent that can transmit it and , you know , expose and transmit to people. But they have shown that with prolonged or intense exposures , that there can be some cases where humans that are infected can transmit to other people. The risk is low. It does require heavy or prolonged exposure. It isn't just through casual contact.

S1: I want to talk a bit more about transmission because on M.S. now , Harvard Environmental Health professor Joseph Allen said though he doesn't think the overall threat to the general public is high , he thinks he thinks it's low. He did have concerns about the science of transmission. And I want you to hear this clip.

S3: So I think we've been underplaying exactly how this is spread that you need some prolonged close or physical contact , when in fact the evidence suggests it can be transmitted by people who aren't in close contact. And in fact , it can happen rather rapidly.

S1:

S2: I would say this , that , um , like other hantavirus , it definitely can be transmitted from rodents to humans. And the human transmission , um , has occurred , but it's been very limited in the cases that we have seen. They have been people that were symptomatic and people who were exposed for prolonged periods of time. That being said , is it possible that it could be transmitted under less severe circumstances ? The answer , of course , could be yes , but I would say this this virus occurs naturally in Argentina and Chile and Uruguay , and they do have some cases there every year. And despite that , we're not seeing widespread spread transmission and we're not seeing common transmission between people. So although it is possible , I don't think it is the main means whereby this disease is transmitted.

S1: I think many people are reminded of the coronavirus pandemic when hearing about this virus. Tell me , I mean , you're not seeing widespread transmission in Argentina , but but tell me , how is is hantavirus different from the coronavirus ? What is it that prevents it from spreading the same way as coronavirus did.

S2: Well , it's it's a completely different viral family. So you have to take that into account. And as I already noted , the whole hantavirus family in general , other than Andes virus , has never been shown to be transmitted from person to person and via an aerosol route from a person to another person. It is spread by aerosol from the rat or the mouse , depending on which species you're talking about to people , because either the rat secretions or droppings or something that they contaminate , it somehow gets into the air. But if you look at the , um , coronaviruses in general , in Covid 19 virus in particular , it specifically is a respiratory virus. It's a respiratory illness. And so the virus gets in. It replicates in the respiratory tract and then it is exhaled into the air. And for the um The hantavirus is in general , that doesn't seem to be the means of transmission. So that's why it's so far , it doesn't really appear that human to human transmission is a major means of transmission and really requires close , prolonged contact.

S1: And the Covid also seemed to to mutate quickly as well. Right.

S2: True it did. And this is similar to the Covid viral family. This is an RNA virus. And they do tend to mutate more significantly than say , a DNA virus does. But again , this virus we've been aware of it for a number of decades now. And they do get cases regularly. And we just haven't seen this as a problem where it commonly causes human to human transmission. I think it's important to look at the situation when you're on a cruise ship where people are in very close proximity with each other for long periods of time. They eat together. They they do activities together. There's only , you know , a limited amount of air circulation because ships are a very contained environment. And so it really is sort of the perfect storm of a place where if something is able to be transmitted person to person , that it would be likely to do so. And I think the fact that we haven't seen similar episodes before does support the fact that this really is an unusual circumstance and not very likely to be a problem in a more general sense.

S1: I want to turn now to just the general response to to this , because , you know , many top officials at the CDC are no longer working there , and the US is no longer part of the World Health Organization.

S2: I'm very concerned about the the whole public health community and , and how we communicate with each other. But I will say this , that even though the US isn't officially , um , working with the W.H.O. on a regular basis , we have a number of other entities , including some of the larger states in the United States that are still in contact with them. And I would also say that the CDC has been working with W.H.O. in this particular circumstance , and the entire public health community in the United States , from the federal to the state government to the local health departments , are all in contact with each other and working together so that we can respond in any way that's necessary. So I wish that the the public health community obviously would get more support and that we would continue to work together at all levels. But I do feel like the particular response that's taking place now is appropriate.

S1: And , you know , when we initially reached out to you , you were receiving an update from California public health officials about this , this outbreak on the boat.

S2: And that's because they had finished their part of the trip and had left the ship before the outbreak was actually known. Um , they are being monitored appropriately by their own health care providers and the public health system. And we know that for any other Californians who would have been on the ship that are obviously being returned now , that they will be monitored as well.

S1:

S2: There's what we call quarantine and what we call isolation. Isolation is what you do for somebody who's actually ill. So if somebody actually were to come down with symptoms or to test positive for this , even if they didn't have any symptoms , then they would obviously be placed into a setting where they could be cared for as they needed , and also where they wouldn't be able to infect other people. The other is quarantine. And quarantine is where you take people who have been exposed to a disease that you believe is contagious , but who are not showing any evidence that they've been infected , and then you observe them for a period of time in a safe setting , so that if they do develop any evidence that they've been infected , that you can intervene early on.

S1: And again , what are symptoms and what does treatment look like for this. Because it could take up to eight weeks to to show.

S2: Right , right. One of the difficult things in , you know , particularly when you need to quarantine people that have been exposed is that this is a disease that can have along what we call incubation period , which is the time from when you were exposed to when you develop symptoms. Most people don't take that long , but some can. And of course , you need to watch people for that period of time. The initial symptoms are similar to other febrile viral illnesses. And that's one of the reasons why it took a period of time for this particular virus to get identified. Because when the first cases occurred , um , there were many , many other things they needed to think about besides hantavirus. Then once it gets identified , then obviously at that point in time , you start putting things into place again to monitor people , to quarantine and isolate as necessary. With regard to treatment , hantavirus don't have any specific treatment available. There's not any vaccines to prevent infection , and there's not any particular medications that have been proven to actually treat the disease. However , what's interesting about the people who do develop the severe form of hantavirus disease that , um , very good supportive care , meaning being in a hospital , in an intensive care that can give them the support that they need , and in some cases something called ECMO. If they develop really severe disease to the point where their lungs are no longer functioning properly. The ECMO has been shown to increase survival. And so getting back to your prior question. One of the things that's been taking place as we prepare for for the arrival of these passengers is making sure that if they were to become ill , that they would have access to that life saving treatment if necessary.

S1:

S2: And in terms of the rodent , this particular virus , as I said , is limited to this particular species of rodent that's really only seen in Argentina , Chile and Uruguay. So I don't think that it's likely that the World Cup or any of the other large events that are going to be taking place really are going to have any impact on this.

S1: All right. I've been speaking with Doctor Monday. He is an epidemiologist with Sharp Health Care. Doctor , thank you so very much for joining us today.

S2: Thank you very much for inviting me. I enjoyed this very much.

S1: That's our show for today. I'm your host , Jade Hindman.

S4: Thanks for tuning in to Midday Edition. Be sure to have a great day on purpose , everyone.