A Global Expert Helps Us Understand the Hantavirus Outbreak: Dr. Jamie Childs, Senior Research Scientist in Epidemiology of Microbial Diseases at Yale School of Public Health

Lindsey Smith

Hi, I'm Lindsey Smith, welcoming you to Raise the Line from Elsevier, an ongoing exploration about how to improve health and healthcare.

Today, we are going to focus on the ongoing outbreak of hantavirus that originated with passengers on the Dutch cruise ship MV Hondius in April. The outbreak has led to a number of deaths, required quarantining of passengers across multiple continents, and prompted a CDC level-3 emergency response.

I want to note that we're recording this on May 19th, so facts may have changed by the time you hear this, but we thought it was worth providing our listeners with a general understanding of hantaviruses and what level of threat is posed by this situation.

We're pleased to welcome as our guide Dr. Jamie Childs, a leading authority on hantavirus. He is a Senior Research Scientist and Lecturer in Epidemiology of Microbial Diseases at the Yale School of Public Health, and an affiliated faculty member of the Yale Institute for Global Health.

Dr. Childs' research focuses on the ecological dynamics of directly transmitted zoonotic viruses as well as vector-borne bacteria. Earlier in his career, he led the CDC's environmental investigation during the landmark 1993 hantavirus outbreak in the Four Corners region of the American Southwest.

Thank you so much for joining us today, Dr. Childs.

Dr. Jamie Childs

Glad to be here.

Lindsey Smith

So let's get started. I'd love to start with learning more about your background. Can you tell us a little bit about that?

Dr. Jamie Childs

I will be brief, because it's sort of checkered. I started out as an art student and switched to science. Won't go through it, but I realized that science is just as creative — I misunderstood it. I went to graduate school at Johns Hopkins University and got my doctor of science, after which I did postdocs at the U.S. Army Medical Research Institute of Infectious Diseases, where I worked with hantsaviruses viruses, isolating and characterizing them. After a stint there, I went back to Johns Hopkins as assistant and associate professor before moving to CDC in 1992, where I was an epidemiology section chief and then became a branch chief of the viral zoonoses center. After that I moved to Yale. So I've sandwiched a federal career with a couple of university appointments.

Lindsey Smith

That's really interesting. We're going to get to hantavirus, which is what everyone wants to know about today, but before we get there, let's kind of build on the foundation and make sure everyone listening is on the same page. Before we talk about that specific outbreak, can you walk us through what hantavirus actually is, where it comes from, how people typically come in contact with it, and how long it's been on the public health radar?

Dr. Jamie Childs

Well, it's been on the public health radar, at least the military radar, for a long time. During the UN intervention in Korea, often our troops were more scared of the virus than they were of the enemy. In its most severe cases, they suffered very severe kidney problems, including shutdown of their kidneys and very aggressive proteinuria, and it killed about roughly ten percent of those who received it. We had no vaccines and, often like we have now, we can only treat the symptoms. There are vaccines now for some hantaviruses, but who do you apply them to? Not cruise ship members.

Lindsey Smith

Right. That's really helpful context. Now the situation that we're seeing today involves a specific strain, which seems to be the part that's making all of this so concerning. Can you talk about the specific strain and what makes this one we're seeing today different from other hantaviruses?

Dr. Jamie Childs

Well, yes. Before Andes virus was described in Argentina and Chile, there were no examples of hantavirus being transmitted person to person, so this was a disturbing but limited virus, which caused a number of outbreaks and clusters of disease in Chile and Argentina. Who would have expected it to show up on a cruise ship? Not me, and I don't think I could name any hantavirologist who would have disagreed. But the cruise ship, as far as I know, originated in Ushuaia, the southernmost city in the world, in Argentina, shared by Chile.

Various variants of Andes virus — and I'm not going to bicker over the slight genetic differences — very likely came on board through a passenger. After that, there were a number of cases all within very close contact of this individual. Hantavirus transmission, at least Andes virus, requires very close contact...we may be sharing saliva, who knows, body fluids other than that. Unfortunately a number of people got sick, and it's possible that once they were sick, they may have contaminated surfaces and so forth, which may have led to some other infections.

Now, this is not a pandemic potential. Hantavirus, like many of the other viruses — there's an Ebola outbreak which is far more concerning now — hantaviruses require contact tracing. With Andes virus, you want to know who people were in contact with. You want to quarantine them or, if they're sick, put them in isolation with stringent controls. Normally you would isolate for what is a typical incubation period of twenty-one days or so, although it can be far longer...for two times the incubation period, about forty-two days.

Lindsey Smith

That distinction really matters when we compare this to past outbreaks. So just to play that back for everyone, most hantaviruses spread from rodents to humans. But Andes virus is unusual because it's the strain that can also spread from person to person, and the potential for human to human transmission is really what sets it apart.

Dr. Jamie Childs

Absolutely. It's very interesting, when we first investigated the outbreak in the Four Corners area of the southwestern United States, we could identify not only individuals -- and this was the first study of its type -- you could sequence viruses from the individual patients. Then when we went in and caught Peromyscus Maniculatus, which was the rodent host. We identified that the variants in people were restricted to those rodents caught in their households in proximity.

So even within this one outbreak, there are genetic signatures linking individual human cases with particular mice caught at their homes. An exception proved the rule. We identified some variants from Colorado in an associated case in Colorado, but in Flagstaff, we got a sequence out of a person who had a variant identified as the Colorado variant. Why? Because he had moved from Colorado to that other state within two weeks and had acquired infection in Colorado and was diagnosed in another state.

This outbreak involved a very different disease than our troops experienced in Korea, which was mostly kidney disease. This outbreak involved pulmonary infections and later cardiac complications. They have different hosts. This one was maintained in new world rodents, and it's another group of viruses which are maintained in old world rodents. One of the significant things we discovered was that old world rodents of the genus Rattus, Norway rats, were also infected with the virus. This was identified by Ho-Wang Lee in Korea, who identified cases in urban centers where the primary reservoir is not present. 

Once that observation was made, we were working in Baltimore and found very high prevalence of hantavirus infection in Norway rats, up to 80%. We isolated the virus and showed that it was closely related to the virus that Ho-Wang Lee had called Seoul virus, distinct from Hantaan — this was in rats, not in mice. Very rapidly we showed this virus occurred in rat populations around the globe, work done by Jim LeDuc.

Lindsey Smith

That's really helpful context. So naturally the next question is what treatments are available for those infected by hantavirus today?

Dr. Jamie Childs

Well, they're largely supportive. If you have renal disease, you can use dialysis and other methods. If you have a pulmonary infection, you can use artificial breathing and other methods to overcome the oxygen deficits. So we have medical interventions. There have been some vaccines used mostly in Asia. I'm not sure how great they are, but the problem is who are you going to vaccinate? Hantavirus is an extremely rare disease. You're not going to go into populations and vaccinate for this. I mean, there have been, I think, less than 900 cases reported in nine states since the initial outbreak was identified in the Four Corners area. Who are you going to vaccinate? No one knows, and there are several different varieties of the virus. 

Some, the most significant, are those which are transmitted from mice to people in the West and Southwest. Now we have Bayou virus, which is in coastal areas in the United States. Then we have New York 1 virus, which is in a very closely related mouse, Peromyscus leucopus, which is also the major reservoir for Lyme borreliosis. So it's very interesting and a dynamic situation, and we don't even know how these things may interact with other infections these rodents may have. Complex ecology, and complex problems which don't have easy solutions. It’s very different from what's going on with Ebola right now.

Lindsey Smith

For sure. It is very complex indeed. So let's turn now to the setting of this specific outbreak because it's something that we don't hear about every day. Hantavirus on a cruise ship is unusual.

Dr. Jamie Childs

Unique. 

Lindsey Smith

Unique.  Ok, let’s go with that.

Dr. Jamie Childs

As I said before, I don't think anyone could have ever predicted this situation. Now, here you are on a closed vessel. Close contact between individuals. Fatal occurrences were in people who had very personal contact...a man and his wife and another individual who apparently died along with them and so forth. Although we don't know the mechanism by which it's transmitted, it could be transmitted in saliva, it could be fecal oral or urinary contamination. We don't know the exact mechanism by which it's transferred, but it did infect a fair number of people, including some Americans. 

Andes virus could be fatal in 60% or more of individuals. It's one of the most dangerous hantaviruses. Luckily, we haven't seen that sort of mortality, but we're still tracking these patients because the incubation periods are not over.

Lindsey Smith

I think where I want to go next is your research work and how that lens helps you interpret what's happening in this case.

Dr. Jamie Childs

Well, I've worked on the virus since the 1980s, initially with rats in Baltimore, but I've been involved with outbreaks. I led the environmental team in the Four Corners outbreak. We went into hogans where people recently died, trapped mice, and lent those to the elucidation of the epidemiology of close transmission between mice and people within very limited environments. 

I have spent some time in Korea actually working on Hantaan virus proper with the U.S. military. Although we didn't test for Andes virus, I worked on another hemorrhagic fever virus in Argentina called Junin virus, which causes a very severe hemorrhagic disease, fatal in ten percent or more of people infected. We were catching some of the reservoirs of Andes virus and not knowing it. We were already taking precautions against a hemorrhagic fever virus, but little did we know that we were also catching a virus of a different. Little did we know we were also sampling reservoirs that were infected with hantavirus.

So taking precautions against one severe virus presumably prevented us from encountering Andes virus because we were very careful. We developed and published the field methods for dealing with hazardous viruses and collecting tissues in the field.

Lindsey Smith

That bigger picture research lens is so interesting. With that in mind, let's kind of zoom out a little bit further to talk about the global risk. You have said that this is not the next COVID or pandemic, and the World Health Organization has also come out and said that the risk of a broader epidemic is very low here. 

Dr. Jamie Childs

Absolutely. Totally. The virus, even Andes virus, is totally controllable. It has to do with contact tracing — that is, people who may have been in contact with cases — and the isolation of those who haven't taken special precautions so you don't transmit it to healthcare workers, which has happened, and it's happening with Ebola right now, a more severe outbreak which is occurring as we speak. It's always controllable.

Lindsey Smith

Absolutely. Do you think the response to the hantavirus outbreak has been handled appropriately so far?

Dr. Jamie Childs

I would think so. I think there's been an abundance of caution, but these are viruses that scare the hell out of people. What can I say? They're rare. They're potentially fatal. I think that a little bit of intense caution is warranted. It puts the public at ease. One of the things that can happen is it's easy for people to misread these situations as being that next pandemic or something when it's not.

Lindsey Smith

I think it's really helpful to hear your perspective and put the general public at ease. I want to talk about a bigger question now about where we stand today compared to a few years ago. Do you think the global health system is better prepared for a pandemic now than we were before COVID-19?

Dr. Jamie Childs

I am very sorry you asked that, but I will answer. I think we are much, much worse off. For example, when I was on an Ebola investigation in former Zaire, we worked with WHO, we worked with Médecins Sans Frontières, and we enjoyed close cooperation with USAID. We have no more USAID. We're no longer working with WHO. We are in a far worse situation. 

USAID supported a lot of basic infrastructure improvement in places in Africa which needed it. The Ebola outbreak is a prime example. We no longer have the teams in place, or the cooperation with these international organizations, to effectively respond. CDC and MSF and WHO as teams were critical in controlling some of these outbreaks. Those collaborations, that funding — gone. No, we are in a far worse situation than I could ever imagine with our public health infrastructure, not only overseas but in the United States. 

Lindsey Smith

That is a critical insight regarding the coordinated effort to respond. Finally, I'd like to bring my last question back to our audience. We have many students and early career professionals listening in. What's your advice to them about considering a career in healthcare, research, or education today?

Dr. Jamie Childs

Well, I've taught at two schools of public health, at Johns Hopkins and at Yale, and I've taught many MPH students and PhD students. It's a hard road to hoe right now. Futures are uncertain in areas of infectious disease and other areas of public health concern, but if you love it, go for it. It's endlessly fascinating and it's extremely rewarding. Not only are you doing good for people, you'll also be involved in absolutely enticing situations which are not available to most people, and you can get addicted to the work that you do, and you should. Work hard and if you like it, go for it. It won't be easy, necessarily, but all things change in time.

Lindsey Smith

It won't be easy, but it might be worth it. That is valuable advice.  It’s also a great reminder that the next generation will play a huge role in tackling the next healthcare challenges that we see. Before we wrap up today's episode, is there anything that we didn't cover that we should have?

Dr. Jamie Childs

Well, we didn't really cover Ebola, but you can cover that next time.

Lindsey Smith

Let's get into it a little bit now. What is your take on the Ebola outbreak?

Dr. Jamie Childs

This is a serious, serious outbreak. It was described very recently, but there had already been close to 200 fatalities and hundreds and hundreds of people suspected. The outbreak first came to public health attention when a healthcare worker died. That usually happens much later in Ebola outbreaks, after there have been community cases and people going to healthcare centers in which there's often not the equipment needed for proper isolation and quarantine of those patients, and healthcare workers are often at risk. 

The problem with healthcare workers getting infected is you can close down hospitals — you'll lose physicians, you'll lose nurses, you'll lose janitors — and people often don't want to send their sick ones there because they see that people are dying in hospitals. So it can lead to individuals trying to treat patients at home. 

Ebola also requires very close personal contact — blood, feces, vomitus. In parts of Africa, traditional burial ceremonies involve cleansing the dead, and you can't do that. That leads to more transmission and it's really demoralizing to people when you take a body and disinfect it and put it in a body bag.

But this outbreak is in former Zaire and it's in Uganda and maybe in Sudan. One of perhaps the fortunate things is it's not one of the more virulent Ebola strains. This is the third outbreak caused by this Bundibugyo virus, which as I said has lower fatality. But who knows, all bets are off. It's going to spread widely. It's already in some urban areas. 

We saw what can happen during the 2014 outbreak in West Africa, which for reasons I don't understand didn't spread farther. But this is a scary situation. I think it's not a global pandemic threat at this point. We'll probably see cases resulting from individuals who may travel to other countries within or outside Africa. But this one's going to be tough to control. There's no vaccine for this strain. There are some vaccines which have been used for the Zaire strain of Ebola, which is much more severe. Stay tuned.

Lindsey Smith

Thank you for sharing your insights on the Ebola outbreak. That is a great way to close out today's episode, and this is something we all need to be paying attention to. 

Dr. Childs, thank you so much for sharing your expertise and perspective with us today. It has been a pleasure.

Dr. Jamie Childs

Pleasure to talk with you.

Lindsey Smith

That does it for today's episode. Situations like this remind us just how interconnected our world is and how quickly local events can have global implications. We're grateful to Dr. Childs for helping us better understand both the science behind hantavirus and the broader context for this outbreak. His decades of experience offer a valuable perspective at a time when clarity really matters. We'll continue to follow the developments in this story and we encourage our listeners to stay informed through trusted public health sources as more information becomes available.

I'm Lindsey Smith. Thanks for checking out today's show. Remember to do your part to raise the line and strengthen the healthcare system. We're all in this together.