Ep. 649 - New Avian Flu Developments – Have the Risks Changed?

A new year brings new questions and more insights to the topic of Highly Pathogenic Avian Influenza. Dr. Mike Brasher is joined by leading experts in the field of avian influenza, Dr. Dave Stallknecht, Dr. Richard Webby, and Dr. Jennifer Ballard to discuss the current status of avian influenza, what we’ve learned since 2022, and what we still don’t understand. Recent changes have been noted in the genetic code of the circulating virus, but what does this mean for the risk it poses to birds, mammals, and humans? How do we study these changes? What waterfowl species are most affected, and do we understand why these effects differ among species? Also discussed is recent science about risks to hunting dogs, what hunters need to do if they observe sick or dead birds, why hunters should be vigilant about being tested for avian flu if they feel ill, and how we can all work to reduce the likelihood of the virus becoming more severe. Tune in for an information-packed episode that is of growing relevance to everyone.

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Host

Mike Brasher

DUPodcast Science Host

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Ducks Unlimited Podcast is a constant discussion of all things waterfowl; from in-depth hunting tips and tactics, to waterfowl biology, research, science, and habitat updates. The DU Podcast is the go-to resource for waterfowl hunters and conservationists. Ducks Unlimited is the world's leader in wetlands conservation.

Mike Brasher: Hey, everyone. Welcome back. I am Dr. Mike Brasher. I'm going to be your host on this episode. We are recording this on January 6th, 2025, so happy new year to everyone out there. We are, on this episode, going to be revisiting a topic that's been, well, we've had episodes about this each of the last two, if not three years, and that topic is highly pathogenic avian influenza, and we're bringing back a couple of our guests that have appeared with us before and a brand new guest to provide additional expertise on this topic. I'm super excited about the quality of the experts we're going to have on this, covering, well, hopefully all the questions that you have. And so I'm going to actually let them do the introductions. And so first, I'm going to go to Dr. Dave. Introduce yourself to our audience, Dave.

Dave Stallknecht: Yeah, I'm Dave Stallknecht. I'm a professor emeritus at the Southeastern Cooperative Wildlife Disease Study at the University of Georgia. And my particular interest is actually wild birds. Disease in wild birds, right? Yeah, yeah. And I've been really studying influenza since the dawn of time. I guess it's since the 1980s. Probably before you were born, Mike, but anyways.

Mike Brasher: Maybe so. Well, it's great to have you back with us. Now I'm going to go to Dr. Richard Webby. Introduce yourself again to our audience.

Richard Webby: Hey, Mike, and hi all. I'm Richard Webby. I'm at St. Jude Children's Research Hospital in Memphis, Tennessee. I've been called many things over the years, but I consider myself a virologist. Yeah, much like Dave, we've been working on these viruses for a number of years. We tend to come at it from sort of a more of a human health perspective, but again, we team up with Dave and a lot of other folks who are doing good stuff in the field to understand this virus.

Mike Brasher: And then our new guest on this episode, or actually on the Ducks Unlimited podcast period, is from our neighboring state of Arkansas, Dr. Jennifer Ballard. Jen, introduce yourself to our audience.

Jennifer Ballard: Thank you so much for having me. I am the State Wildlife Veterinarian with the Arkansas Game and Fish Commission, and so I kind of create the bridge, I think, between researchers like Dr. Stolnik and Dr. Webby and our hunters here in the state of Arkansas.

Mike Brasher: Well, let me just again say thank you to each of you for joining us. Thank you for what you've done throughout your careers and especially over the past few years responding to this challenge that has captivated a lot of us in certainly the waterfowl hunting space and have caused us to keep an eye on it and ears open and obviously has far-reaching implications beyond. just our sort of waterfowl audience. And that's kind of one of the things that we want to eventually get to. Dr. Webby, you're going to be able to tell us some of the latest on what we've learned about the risk that this poses to humans. Dr. Ballard, we want to hear from you about what you're seeing in Arkansas, what you're hearing from some of your hunters. To start with, though, I think I'm going to turn to Dr. Stalneck and have him give us sort of the high-level overview of the current status of things. I mean, this conversation could last for two hours, but we're not going to do this. And so, Dave, I know all three of you have given many, many talks about this, but like right now, when someone comes to you and asks you for the latest update, where are we in our understanding? Where are we in the state of H5N1 high path avian influenza out there right now.

Dave Stallknecht: Okay, as far as the wild bird situation, it's a little difficult to say. It's obviously still here. Dr. Wemme will talk about how it's changed probably throughout the years. It's been a lot of genetic change in the virus itself. But long story short, in waterfowl, We've detected it every year. It seems to be reduced prevalence since it's the initial year 2022, 23. What we're trying to do right now, we got a lot of data from the Mississippi Flyway. That's specifically where we're working. The other flyways I imagine are the same, but I'm not really sure. But long story short, waterfowl are the reservoir. It can be found in ducks and geese pretty much any time you look, sometimes higher prevalence, sometimes lower prevalence. What's been interesting, what we have found in the last several years, is that it seems to be following the same trends, seasonal trends, as low path influenza, and basically with sort of a low prevalence of H5 in September, October, kind of early. It comes in strong in October and November, and that's when it also probably spills over into geese, and then it poops out. And in the spring, it's pretty much clear. I'm sure it's there, but it's incredibly difficult to detect. So we're seeing a lot of trends now that probably will help us understand risk. As far as spillover into mammals and all that, that probably relates to waterfowl mortality and feeding on carcasses. And I want to bring up one other thing. There's a reservoir in in waterfowl, but there's probably something parallel going on in marine birds, also, on both the Pacific coast and the Atlantic coast.

Mike Brasher: We're not really sure how.

Dave Stallknecht: Go ahead.

Mike Brasher: Dave, you said marine birds?

Dave Stallknecht: Yeah, yeah, gulls and that sort of thing. And there's been a lot of mortality in those species, and we're not really sure how that's all connected, if it is connected, between the ducks and marine birds. So maybe two separate reservoirs going on right now.

Mike Brasher: So Dave, when we look back, maybe, I guess, what was that? Was it, this is 24, 22? Was it fall of 22 when this really blew up on us?

Dave Stallknecht: Yeah, yeah. It really blew up. And it's interesting. It blew up in actually the spring of 22. And that's really rare. We don't see high prevalence of flu in the spring, ever. Not in ducks. We do in shorebirds and that sort of thing. And then it carried through until to that early staging period in 2022. And like in Minnesota, we find prevalence of really high, 50% of the birds were positive for high path. And that has since changed. The last two years, when we're looking at sort of the northern staging areas, pre-migration, or the early teal seasons in the south, we're really not finding much. probably from a national surveillance standpoint. I mean, viruses are trickling in, but it's not a high prevalence, which is good news. I mean, basically, the risk of exposure is relatively low at that point in time, which kind of factors into the human risk on the harvest side also. So seasonally, there's a big difference in when this virus can be detected or how easy it is to detect. Now, we've got three years data, OK? And I'm going to hang my hat on that. So, we'll see what happens, but it sort of follows what we'd expect from sort of a population immunity kind of standpoint. The other thing that's interesting is with antibodies, we're looking at serology, and we're seeing specific age class related differences in susceptibility also. And this probably you'll factor in if you want to talk about it later, the geese mortality. It's probably a specific age cohort that is at risk there, not the whole population. And I think that has probably some pretty big implications to management and also human risk and everything else.

Mike Brasher: Yeah, you've touched on a couple of the issues there that I wanted to talk about. You've learned a lot over the past three years in terms of how that population immunity, as you kind of talked about it, has developed and how we see that sort of increase seasonally. And tell me, as we… If we go back to like spring and early summer of this year, maybe even throughout summer, the detections of this virus were, tell me if I'm wrong, but were probably at the lowest they had been in the past three years. We got to a point in August where there were no detections of live H5N1 virus. in maybe anywhere in Canada, I'm not sure if that's exactly true, but it was certainly a big portion of Canada, to the point where USDA APHIS was poised to rescind their restrictions on importing harvested game birds. And so it felt like in this summer and coming into this fall that maybe something had changed and hopefully we were not going to see the intense seasonal occurrence of the virus this year the way we did in the past, but it certainly seems like that changed in November and then into early December. We heard some early reports from cackling geese in Oregon, ring-necked ducks in Florida, but at that point it seemed to be kind of isolated, at least based on what I was hearing and maybe seeing. But then November, December rolled around, we got some cold weather, and then it seemed as though the reports of symptomatic infection in snow geese and even white fronts really just jumped high up on the chart. Am I characterizing that correctly?

Dave Stallknecht: You've got it right. And it's an interesting thing, and it may relate actually to the specific subject. And in ducks, normally, what you see is a high prevalence during that early fall. But it's a high prevalence of all influenza viruses, not all the subtypes. And this year and last year, we detected a normal amount of probably low-path viruses that are there. H5, historically, is not part of that. Generally, it does not show up early. Seasonally, it's a little different. And the low-path H5 viruses that were in North America prior to this one coming, generally, you'd be more likely to detect those in later fall and the winter. And this one seems to be following that same course, with one big exception. With the low path H5, we never really saw high prevalence of it. You pick them up here, there, everywhere. Little peaks, but not great peaks. This high path H5 just rips when it gets into a waterfowl population. The prevalence hasn't been as high as that first year, but it's still elevated when we do detecting. So again, it's following these patterns. That's the good news. The bad news is we really don't understand why we have these patterns, okay, even with low path. And we kind of think, I kind of think, I don't know if everyone believes this, but I kind of think it's probably related to probably fluctuations in the population immunity where basically it lasts for a year or whatever. And so you would get the same seasonal kind of trends year to year. We don't know this. Maybe the only thing good about high-path influenza is that this is the first time we can actually follow a specific serotype serologically through the waterfowl population. And I think we'll learn something from it. It's a long way to go. And again, we have three years to date, and I don't want to say too much about it. But it looks like some trends are developing. Let's leave it at that.

Mike Brasher: But so Dave, I want to jump in here, and I want to acknowledge that we have two other experts here in this field on the call with you. And you made a few comments about, well, we know this, but we don't know this. And so I want to give Dr. Webby and Dr. Ballard an opportunity to offer some thoughts or ask you any questions that they may find of interest, given what it is that you just talked about.

Richard Webby: Yeah, maybe I can jump over a few things, sort of coming back to this point that this season seems to be a little bit more activity than we have seen maybe over the past 18 months or so. There's a lot of hand-waving going on with this, but so as Dave said, perhaps it's some sort of cycling and population immunity to the virus and the bird populations. But one thing that's also new this year, so I'm putting my virologist hat on here, Let me start that again. So the flu virus basically has its genetic elements on eight individual gene segments. And what happens is when two different flu viruses get in the same cell, they replicate and they basically mix and match. So you get all this progeny virus coming out of that infection that has gene segments derived from either parental strain. And what that does is it sort of, if you like, supercharges the ability of flu viruses to evolve. and mutate. And what we've seen since the H5, this version of the HyPath came into the Americas in the very, very end of 2021, we've seen a lot of this go on. So this virus that you know, our friends in Europe gave to us. You know, it came in and it started to interact with all of the, as Dave mentioned, the low path versions of flu that we have in our, you know, wild birds over here. So, it went through this patent resort, mixed and matched, made all these different versions of itself. One thing that was constant through that whole process was that the two proteins that sit on the surface, the H5 and the N1, These two were always the same. They always were the same from the viruses that came over from Europe. The virus that's come down from Canada this year and probably even further north, started further north than that, that's changed. So, it's still an H5N1 virus, but it has that H5 from Again, the European version of the virus, but the N1 is not that European version. It's a local version of that N1. So this is a combination that we haven't seen yet in the three years of dealing with it in this continent. it's possible that that's changed the biologic property of the virus a little bit. We know these two proteins are really super important for the virus, for how it behaves, for how it infects, for how it causes disease. So again, yeah, Mike.

Mike Brasher: Where do we, to help people understand how you all keep track of that, how you study that, how you're able to identify, okay, it's still H5N1. You don't have to get like super technical. I just want people to be aware of some of the data that's collected and the type of work that's going on. And so, it's still a H5N1, but then there's all these different little subtypes. I mean, there's a lot of work that goes on here, some of which is in your lab, I think. But give people an idea of the amount of surveillance and work that goes into tracking some of these mutations that you're talking about.

Richard Webby: Yeah, so I guess it's the equivalent of like 23andMe for viruses, right? So yeah, we, and it's not just we, so there's a lot of both academic groups. APHIS, of course, does a lot of NDSL, does a lot of this as well. So You know, when folks like Jen and Dave get a sample from a bird that comes into their shops, you know, they'll send them to folks like us, like NVSL, and we'll sequence them. So we go in and look at the genetics, the genes of these viruses, and that tells us a lot about them. So they're, again, much like sort of ancestry.com, 23andMe, where we can trace the ancestry of, you know, you, Mike, if you sent us a piece of your DNA, we'd do the same thing with these viruses. So we'll sequence them, and that tells us a good deal about where they've come from, whether they are related to those viruses that come across from Europe, whether they're our own sort of native flora. So there's a lot of that going on. Sequencing, generating the data, people looking at them, experts can say, okay, this is different, we haven't seen this before. And even then, looking for specific, even one mutation within that sort of whole soup of viruses. Again, looking at that, particularly from a human health perspective, there are some key changes that we look out for. So a lot of this goes on. There's thousands and thousands and thousands of these viruses getting sequenced every year, and that's where that information comes from.

Mike Brasher: And that's one of the things that people are hearing a lot about right now if they're tuning into the news on these new avian influenza cases that are being detected in humans and why it is of concern. Because the more times that infection occurs, the more opportunity there is for that mutation. The more humans that we have infected with this, the more opportunity there is for a mutation to occur. in a way that we don't want to see, right? And is it particularly risky if someone, let's say, is infected with a human influenza virus and they also contract the avian influenza virus at the same time? Does that matter? How does all that work? I mean, that's kind of the way I think about it, but is that totally off base?

Richard Webby: No, no, not at all. You've done well. Again, so I think, although in this part of the world we've really been dealing with this virus for three years, globally this is a 25-year-old problem. And I think it's pretty clear from those 25 years while this virus is circulating in birds, it doesn't really pick up those mutations that make it more infectious for humans and probably most other mammals. And that's why we worry when we see individual cases in humans, because it's when it gets into humans and start replicating, that's going to pick up those, if you like, adaptive mutations that switch it from being a duck virus to being a human virus. So that's why we really worry about that. That's why when someone gets infected, we want to sample them, we want to look, we want to see what sequence and see what that virus is. The other point you talked about, Mike, you know, we talked about reassortment, where two different flu viruses get together, mix and match gene segments. That's sort of one of the other, at least a theoretical concern coming into the human flu season, which is, you know, at least in our part of the world here. in the Southeast is starting to pick up a little bit. That someone or something might get infected with one of these high path avian flu viruses, a human flu virus, and they'll do their thing and switch out gene segments and something may come of that that's a little bit better adapted to humans. That in itself is not gonna be the complete trigger. We know it needs other specific mutations in some of those avian parts as well. But that's a concern. And the NY, people, particularly if you're involved in the poultry industry, it's probably a good idea for hunters as well to get your flu vaccine as well. It doesn't probably protect you from the H5 high path, but it'll lessen your chances that you're going to get infected with both.

Mike Brasher: Yeah, we'll come back to that here a little bit later on as we talk about some of what we've learned regarding some of the new cases that have sprung up, largely associated with the outbreak that we've seen in dairy cattle. We'll come back to that here a little bit later on. Jen, I want to go to you right now, Dr. Ballard, out there out of Arkansas, as you were kind of listening to me talk about my view of this situation as we got into the spring and summer, and then we were kind of hopefully optimistic as we got into the fall and winter that that kind of lower prevalence that we were seeing may continue into the fall and winter. Were you thinking the same thing, or were you thinking, oh, this is just a matter of time before we see this again? Because you've seen it in your state each of the last, now, three years.

Jennifer Ballard: Yeah, we have seen it. The first outbreaks, other states were seeing it in spring of 22. We saw it for the first time in fall of 22. I really haven't been brave enough to make any guesses or projections about high path flu. I think all bets are off when it comes to this disease, until we know more, because as Dr. Stolnik and Dr. Webby have pointed out, for our continent, it's still a relatively new issue. The one guess that I have made is that this is probably going to be cyclic over time, related to the same patterns of immunity and virus. adaptation that the other two have discussed already. And so, you know, in 22, we had a fairly large outbreak, and it was pretty quiet last year. And this year, it's kind of ramped up a little bit more. It's kind of in between. And I think, you know, we may continue to see cycles like that. But I think only time will tell, really.

Mike Brasher: Now, from your perspective in your job, you mentioned at the outset that you're kind of the bridge between different parts of the public and a lot of the researchers that are looking into this issue and collecting the information and providing it for consumption, you know, transmission to, so to speak, to the people that are interested in the information that need the information in your state. We're talking about waterfowl hunters, we're talking about commercial poultry producers as well, right? Arkansas has a fairly large footprint in the commercial poultry industry in this country, right?

Jennifer Ballard: Absolutely. I won't name any particular companies by name, but we do have a number of companies that operate here or are based here in Arkansas. They're not necessarily in our prime waterfowl areas, but we're getting reports really from all over the state. you know, there's going to be some mixing there, especially in what we call backyard poultry or poultry that are kind of privately owned in people's yards, not necessarily kept within houses. But certainly we're in close contact with our Department of Agriculture, keeping tabs on what they're seeing and what they're responding to and trying to get that information out. I've met with the Farm Bureau a few times in past years, just trying to get that biosecurity information out because that's going to be the most important thing between being out in the field and possibly having it on your shoes or getting it on your equipment versus getting into these poultry houses. That's a place that we have some control and one of the areas that we can actually do something to prevent that spillover.

Mike Brasher: I think what I want to do right now is take a break. I want to come back and talk about a number of other things, and Jen, I'm going to start off with you by kind of, I guess, revisiting the way this played out in your state in late November, maybe early December. You'll have to help me on the timing, what you saw in terms of, you know, infections, what species were primarily affected. I have a lot of co-workers and friends here in Memphis that hunt in Arkansas. So I certainly have stories that they shared with me and videos they shared with me, but I want to hear from you. And then also this is an opportunity for us to communicate to the hunters on those types of things, what they need to be doing. We also have some questions about like, what does this mean for my retriever? Are they at risk? We have some information there. So that, human health risk, other things we'll finish off the episode with, but right now we're going to take a break. Stay with us, folks. We have all that information and more coming your way. Hey everyone, welcome back. We are again joined by Dr. Dave Stalnick, Dr. Richard Webby, and Dr. Jen Ballard. We're talking about avian flu, and I'm gonna go right back to Jen and kind of have you give us a report from your state on how this played out. When did your phone or email really start blowing up with reports of sick or dead birds in your state? What species were they? And then how did y'all respond?

Jennifer Ballard: So each year that this is ramped up, it's been fairly predictable late November right around Thanksgiving or just thereafter. I'm assuming that's related to when certain birds arrive and what the migration patterns look like, and they can be a little delayed from year to year, but it's been fairly consistent so far. Most of our reports for sick birds have been in snow geese. And the very first year, it was largely immature snow geese. And the last two years, we've had a few more of the more adult age class represented. But either hunters are going out and finding them just dead in the field, people are driving down the highway, they'll see some dead on the side of the road. Or one of the more interesting things that we get reports of, we'll get videos of birds swimming in circles. Sometimes, they've got a bit of a head tick or they just look docile. They're just sitting there. People can walk up and pick them up, and that's really problematic because people do tend to pick them up and want to take them to a rehabilitator or a veterinarian, and so that has the risk of just kind of spreading this around because they don't necessarily look sick when they're in that condition of just appearing very docile. They seem injured or something like that. But those are just the ones that are sick. You know, this is circulating in waterfowl populations more broadly. There are birds flying around that look perfectly normal that are going to be infected with the virus and potentially shedding the virus. So we have to keep that in mind that not every bird that's actively infected or actively shedding is going to look sick. And those signs can be really subtle.

Mike Brasher: And then, so you noted that again, it's mostly snow geese. Ross's geese in there as well. Is there much of a differentiation as you can tell in terms of susceptibility between Ross's and snow geese?

Jennifer Ballard: We've had both of them reported, and they're so gregarious, and we have really large flocks in our state, so kind of lump those lighter geese together in that conversation.

Mike Brasher: I also had people telling me this year they saw more white-fronted geese affected than they did either the past two years, so more white fronts. as well as more adult birds. And that was a bit concerning, I think, whenever I first started hearing that. Of course, these are anecdotal observations. It's very difficult. Dave, I think I've heard you talk about this before. It's very, very difficult for us to get an estimate, reliable estimate, on the percentage of the population that develops these symptoms, the percentage of the population that that dies as a result of this. I've had Dr. Julie Lenock, our colleague with USDA APHIS, tell us before, it's like, if you see a duck or goose out there nowadays, you just, you're best to assume that it has been exposed to this virus for the most part. Some of them don't show symptoms, some do. And so, Dave, I want to go to you with sort of this question. What do we understand in terms of what's driving the differences in susceptibility and likelihood of showing those, I should say susceptibility, that should be, I guess, showing symptoms and then maybe showing visible illness or mortality, because there are a lot of apparently healthy-looking birds that have this virus. What do we know about differences among species?

Dave Stallknecht: I'm not going to get into susceptibility. If I knew the answer to that, I would be world-famous. But I will say that what we don't really understand as far as waterfowl conservation, or actually wild bird conservation, because it blends into the marine birds too, we do not understand the problem yet. And what I'm getting at is we have a big, long list of a lot of mortality. That's a terrible thing. It's not a good thing. But we don't know if that mortality is enough to really affect the population over the long term. We don't have a clue if that. And what we have now, when we see a lot of birds, we don't have good indications of how many are out there in the landscape. Waterfowl are difficult to detect, especially the smaller ones. Ducks, geese, snow geese are one of the easier ones, for sure. What we're seeing, though, is that on one hand, we see a lot of mortality. But on the other hand, at least with blue-winged teal, if you sample blue-winged teal in September after all this goes on, about 90% of them have seen the virus already. and survived. And we saw the same thing with snow geese in 2022. So we don't know how resilient these populations really are. And I think this is something we need to get a handle on because it has management implications. Do we really need to overreact? Can we actually do something to just enhance the population to sort of counter mortality or whatever? So that's sort of where we are right now is really trying to understand what the problem is from a bird conservation standpoint. I think we have a clear… Actually, I think this probably falls on spillover to domestic animals and also the human thing. really trying to understand what the problem is. And so we can maybe figure out if we have to react or how intensely we have to react.

Richard Webby: Could I just maybe add to that too? Because I totally agree with Dave. We're a little bit blind in terms of the differences of hosts for this virus. That doesn't even go just within birds. It's within some of the mammals that are getting infected with this virus as well. we just don't understand. But it's not an easy thing to actually get an answer to, right? So, you know, there has been some really, really nice studies where folks have taken some of the, you know, particularly with the ducks, taking them into laboratory settings and done some controlled experiment, controlled infections where you can get a little bit, you know, do they get, does one bird get sick than the other? You know, the stuff that, you know, Dave and some of his guys are doing is probably the best way to do it, sort of out there in the real world is looking serologically, so how many have showed evidence that they've had it before and survived. So yeah, really, really important questions, but they're not really easy to get answers to, unfortunately.

Mike Brasher: So I'm going to ask another question here. I'm trying to really get it. It's something that I've speculated about. Maybe I've even heard one of you talk about it as well, but somebody was telling me that I interviewed that, you know, Whether a bird develops symptoms first, and if that infection is severe enough to cause mortality second, could be related to viral loading, how much of the virus they take in. And y'all tell me if that's incorrect, but I want to say it may have been Dave that you and I were talking about when that came up. And so that causes me to wonder whenever people ask me about snow geese or Ross's geese, why symptomatic infection seems to be so prevalent in that group of birds. Do we think it could be a viral loading, a difference in viral loading, viral intake that those birds experience just as a result of, as Jen pointed out, their highly, highly gregarious nature? Do we have any insight on that? Dave? I had to call somebody out.

Dave Stallknecht: I think it's failing at it. We know what matters. It's probably species specific. We've seen this with high path in ducks, as far as how much it takes to infect a duck. And specifically, we were compared to a bunch of species, but what I remember are mallards, it would take like, you know, two logs, three logs to really get things going. With wood ducks, you could sort of wave the virus over them and they would die. It got down to like 10, you know, a virion. I mean, it was ridiculous. So it probably matters a lot. And that's the problem when you're trying to figure out why something is happening, because there's that factor and about nine more that kind of add on to it. And all interacting, and it's really difficult. For example, you can do these studies in the lab, and they're really valuable and they're really important for pathogenesis and everything else. But what you don't see in the lab are ducks that I've seen, 13 infects previous infections with low-path influenza viruses. some of which are the same subtypes. That's what you don't see. And that's where it gets really tricky to kind of look at this and say, this is what causes it. This is the big difference. So with geese, for example, one of the things that might be happening there, unlike ducks, they are not exposed to low-path viruses. And then, on the other hand, ducks are more resistant, just naturally, because they're a duck. dead than a goose.

Mike Brasher: So there's a lot going on. What do you mean by that? They're just more naturally resistant because they're a duck than a goose? There's something behind that.

Dave Stallknecht: Well, if there hasn't been as many probably lab-based studies on geese, for obvious reasons, they're big and they're hard to do. But with ducks, I mean, a lot of experimental infections with high-pad virus Really nothing happens. I mean, I think, you know, they just, they're from, I'm talking specifically of mallards, that's what's used in the lab mostly. But in a lot of cases, they shed fires, they get infected, but clinically, yeah. Pretty normal.

Mike Brasher: So we still don't know a whole lot then? We know a lot, but there's a lot more to know. Okay. That's better put. That's better put. So, all right. I think what I want to do, we still have, we want to kind of, eventually we'll close out and I don't want to, I want to ask Jen and ask all three of you, like, what are we telling people? What do we need to be telling people to be aware of? What are the things that they can do? in various situations. I haven't talked about the dog situation yet. We've got that coming. But I want to go to Richard now and have him give us a bit of an update on the human side of this. It has been in the news a lot here over the course of this year. I think we're at above 60 human cases now. I don't know what the total number there is, but give us an update there, Richard, on what's our understanding of the risk and More infections in humans as of right now, but what does that mean overall in the potential change in the risk to humans?

Richard Webby: Yeah, right. I think we're going to, for this question, we've got to sort of separate what's going on now into two bins. One is what's going on in dairy cattle. and the spillover into domestic poultry operations. And that's where the lion's share of human infections have been detected. Mostly conjunctivitis, either in folks working in the milking parlours that get splashed with contaminated milk, or in those that are depopulating these huge dairy farms where there's a lot of dander and stuff getting blown in the air. So that's going to continue. While that virus is still circulating in cows and doesn't seem to be headed in any good direction right now, then we're going to continue to see that. And again, Dave hesitated to sort of make too much out of three years of activity. I'm going to make too much out of two human infections. I think what's maybe a little more concerning is we've had two more severe cases, so just about everything else except from perhaps one case in Missouri where there was some hospitalization, but maybe not uber severe disease. We've now seen two severe disease pretty recently, one in Canada, and a teenager there who had some underlying conditions, but I don't know where they got the virus from, but got really, really, really sick. And similarly, the one in Louisiana. This was, again, probably exposure to infected backyard poultry. So they had animals in the back, in the yard, apparently, and it was, again, more severe infection. Both of those two severe infections were, if we remember talking about before, this isn't the virus that's causing all the problem in birds right now. It's a new combination. I'll throw out the actual names of these viruses. We're scientists, so incredibly imaginative with our names. So this one is a D1.1. The one that's in cow was a B3.13. So yeah, that's right. So the D11, that's the one that's causing all the problems. That's the one we've been talking about mostly here. So that's the wild bird. That's the one that causes severe infection in Canada, the one that causes severe infection in Louisiana. But at the same time, it was also in some folks that were depopulating poultry over in Washington State as well, where it was more just conjunctivitis. So, what do we make of that? We could say, well, perhaps this new version of the virus is a little bit more nasty when it does infect humans. But we could also say maybe it's an exposure issue, right? Again, with a few people get exposed to this virus the same way they're getting exposed to the cow virus, depopulating birds is just conjunctivitis. These other two, the California, the Louisiana, maybe they got infected by a different route, and that's what causes the increased susceptibility. But that's not an increased disease. That's kind of where we're at from the human front now. CDC, USDA, not USDA, CDC and WHO still have the virus itself listed as low risk, and I agree with that. This is a virus that would still much rather be infecting a duck or a goose than infecting a human. And, you know, if we look at it, we look at the sequence, we look at all the markers in it, it's an avian virus, not a human virus. But that could change. And that's, again, why we're looking at does this D11, so this new combination, make it a little bit more sort of prone to the VA disease in humans? We don't really know the answer to that right now, but still low risk. But these things can change overnight with one or two mutations in the virus.

Mike Brasher: And so for every new human case that comes in, are you ideally, or is your goal to run the genetics on every single instance so that you can catch that very first mutation that would be more problematic when it occurs?

Richard Webby: Yeah, absolutely. And of course, most of that is done over at the CDC over in Atlanta. So any positive human sample will end up there, and those guys will throw the kitchen sink at these samples to get sequence information from that virus. Exactly as you said, Mike. Is there any evidence that during that infection, this virus has picked up some of these adaptive mutations we're concerned about?

Mike Brasher: Okay, so I have a question for you now, and this is a result of a conversation I had with a co-worker. He and some of his buddies went duck hunting. Actually, yeah, they were duck hunting and they were in a location, actually in Arkansas, in a field that had been heavily, heavily affected by by symptomatic dead and dead snow geese. And they were hunting, they stayed out of that field as much as possible, although they did go check a few birds, as hunters are wont to do, you know, looking for bands and so forth. The guy was telling me that a few days after, those two or three individuals kind of started feeling ick. You know, nothing that caused them to want to go to the hospital or anything of that nature. But in that situation, as waterfowl hunters, if you're a… knowing what it is that we're talking about, is there value in being a bit more proactive as waterfowl hunters if you are in a field hunting in a situation where you know you have been exposed to birds or wetlands that have a situation that might have exposed you to the virus. Is there value in kind of being a bit more proactive in going to a doctor and sharing some of that information so that you can catch some of those cases that where humans may have it but otherwise are virtually asymptomatic?

Richard Webby: Yeah, I think that's a really, really good point. I think it's a great idea for two reasons. One, just as you said, Mike, the more information we can get about what happens when this virus infects people, the better off we're going to be. And we're searching for those cases right now. So I think anyone who has had some potential exposure gets sick. Yeah, absolutely. Go into the doc. But actually tell them, you know, I've been exposed to birds that maybe had H5. Otherwise, they're not going to probably test you for it. So, let them know that that's why you're there. So, that's one thing. We'll get more samples. We'll be able to understand a little bit more. But the other thing is, you know, we do have antivirals against flu, but they work best when taken 48 hours after symptom onset. So at the time, you may not feel very bad, but potentially you could go down that pathway to a more severe disease. And this is a virus that can cause really, really nasty disease. And so getting in early to get the tests done and then you can get on those antivirals from a personal perspective makes good sense too.

Mike Brasher: What are the situations in which hunters or other individuals need to be particularly careful or cautious, whether it be they having underlying conditions themselves or a particular situation in which they are more likely to be exposed to the virus? We've kind of already talked about a couple where if they're involved in depopulation efforts with mostly, I guess, commercial poultry facilities, but those are pretty well tightly controlled, I'm assuming. But any other situation, I'm really thinking about waterfowl hunters as our audience here, that they would need to exercise additional, or it would be wise for them to exercise additional caution.

Richard Webby: So, maybe I could have a crack, I'm sure.

Mike Brasher: Yeah, sure. Go ahead, Richard, and then I'll pass it off to Dave and Jen.

Richard Webby: Yeah, I think the biggest risk is, you know, potentially during the cleaning process, right? So really cool studies done by David Swain over at USDA Labs over in Athens, Georgia, just over the road from Dave a number of years ago, where they had, in a laboratory setup, they had infected, I think it was infected chickens at that stage. Then they had ferrets, which we know is susceptible to flu, kind of what we use to mimic human infection in experimental settings. And they just had the infected bird sitting there, and the ferrets didn't get infected. But as soon as they went in there and mimicked cleaning these birds, so de-feathering, taking insides, outside, then they started to see ferrets getting infected with this virus. So, think of that, you know, anything that potentially aerosolizes or, you know, this virus is going to be, well, it actually could be anywhere in the birds, but it's going to be on the inside, right? And so anything you do to expose yourself to what's inside that bird, that increases the risk. So, yeah, it's really the cleaning of the birds that, in my mind, is the biggest risk.

Mike Brasher: Okay. And Dave, I know you have some thoughts on this, so go for it.

Dave Stallknecht: Yeah, I was actually getting back to what Richard said, and I think the biggest risk area that I've seen in the wild bird world is plucking sheds. where you might be processing hundreds of waterfowl in a closed area. And it actually mimics just exactly what Richard said with a lot of dander and a lot of evisceratum and everything else. And I mean, we're not going to get rid of plucking sheds, but you can sure increase the ventilation of them would help. and wearing a mask would help. But that is a risk area. And also with hunters, just physically handling the viscera, especially stay out of the head. The brain loads are ridiculous and hurts. I think if you took some caution there, you'd be in good shape. But I think a lot of this stuff is just not doing things in enclosed spaces and doing things out in the open. And I think that's maybe why we haven't seen a lot of transmission to hunters and all that stuff, because one of your blue skies and not a roof.

Mike Brasher: And it probably makes a big difference. So what about organs like the heart? Are we safe to eat the heart? Assuming you cook it of a duck? Because some people do that. I've done that on occasion as well. I would stay away from it.

Jennifer Ballard: Are you sure?

Mike Brasher: Are you sure? I am sure I would stay with the bird. Okay, so do that at your own risk, as you're saying. It is a riskier part of the bird right now. I don't go for the brain, so you can rest easy knowing that. All right, so here's a scenario for you. I recently purchased a plucker, and it's one of these rotary pluckers. It doesn't have the shield on it. My intention is to use that outside, And how would you advise me? I have my six ducks. I'm not doing this for 50 birds a day or anything of that nature. What would be your recommended sort of guidance to me? Do I need to wear a mask? Remembering I'm outside, small number of birds, go. Would it hurt to wear a mask is what I would ask you. No, it would not. It would not. Yeah, okay. All right? Especially if I'm not feeling well, right? That kind of gets to what we were talking about earlier. If you're feeling ill or something of that nature, then all the more reason to take additional precautions, correct? Yeah.

Richard Webby: And even just to add a little bit to that, again, wearing a mask makes sense. It may reduce your risk from 0.0000001 to 0.0000001, but that's still reducing risk, right? The other thing that, again, done within some of the studies and the live poultry markets through Asia and their de-feathering, is even just to put a lid on it. So you might think you said it didn't have a shield, but what about a cardboard box? There's something to put over the top during that process so you're not getting as much of that guff sort of blowing in your erection. Again, even though the wind's going to take it and send it downstream anyway, but yeah, anything you can do, think about that. Anything, the mask, yes, covering it so not as much stuff gets flown about. Anything like that makes good sense.

Mike Brasher: And hand plucking, let's say, Dave, is probably going to be a touch lower on the risk profile, right? Because there's not as much of that automatic mechanical scattering of dander and such, right?

Dave Stallknecht: Yeah, and doing outside, doing outdoors.

Mike Brasher: Okay. All right. That's valuable guidance and advice there that hunters can employ. And so now I want to go to Jen, and kind of in that same vein, when you are having people contact you and saying, I've got all these dead birds in our field, what do I need to do? Number one, it's good that they were reporting it. That's the first thing that we would tell people, to report it, and you can kind of You can provide some additional guidance on the nature of the reporting that needs to be done now, but what are you telling people that are contacting you to report those situations?

Jennifer Ballard: So to make a good report, the first thing I would say is make note of approximately how many birds are involved and the species that are present. Because when you go to report this to your conservation agency, whether that's in Arkansas or anywhere else, those are going to be the first questions. You know, where was it, when was it, and what did you see happening? So taking good mental notes of that. And then, you know, in Arkansas, we have an online reporting tool. Other states may have a different reporting tool. But getting that information in so that we can start to get our arms around that bigger picture of the cumulative effects of what's happening is very helpful. And then, you know, for us, we've developed, there are disposal guidelines, you know, if you've got like one sick bird and that's kind of out there, but then what do you do if you have a whole field of sick birds? And we've worked with our Department of Agriculture to come up with guidelines for starting to compost those birds, put it in one place, above ground, because a lot of these areas are low-lying, close to the water table. But keep in mind, every state may have some different rules as it pertains to disposing of dead animals. And so, you know, seeing if you can get some guidance in your state, or that could be very helpful. And it's probably not going to make a difference, a big difference, in breaking the overall transmission cycles. But we recognize that there are people out there who are making a living off of this, and it's pretty unappetizing, I guess. It's to go out and to pay particularly for a hunt and have all of these sick and dead birds around. So, totally understanding why some places may want to do those cleanup activities for just aesthetic purposes. I would add on to some of the recommendations that Dr. Stalnick and Dr. Webby made. Definitely cleaning birds outdoors, but that's going to be in addition to the standard kind of hygiene practices that we want to use anytime that we're cleaning any game species. You know, it's generally recommended to wear gloves when you're cleaning game. Make sure you cook it thoroughly. Get those guts out of there and kind of away from the meat as soon as possible. And then cleaning all of the equipment and washing your hands and everything afterwards one step that we haven't often recommended, but if you have poultry in your yard and you're sitting on your porch or outdoors right near that cleaning these birds, that's going to be kind of a problem. So you may want to clean them at another location or try to get that into a trash bag and disposed of in a place that won't necessarily have an opportunity for spillover. And then if you do start to feel poorly, which has already been mentioned, and if your doctor doesn't know what to tell you about that, you can also reach out to your State Department of Health because they are monitoring these situations and they can help you with testing even if you're not feeling sick enough to go into a hospital or anything like that, or even if you just have some basic questions, they're a great resource for information.

Mike Brasher: All right, so a question, Jen, that I got several times, people reported this outbreak on a field in a managed wetland, whatever the case may be, and that there was water in those fields or that wetland in those instances. And they asked me, well, what can I do? What do I need to do? to help mitigate this situation. From a habitat manipulation standpoint, is there anything that we can tell them with confidence right now that we think will have an effect? And one of the things that, and I'll tell you what I told them in response to this question, you can tell me if I'm wrong. I had some ask me if they should drain the wetland, remove the water from that managed unit at that time and then disperse the birds. And my suggestion to them, the way I was thinking about this, that's probably the last thing that we would want to do because you're reducing the amount of habitat on the landscape from that standpoint, and there's no evidence that I'm aware of to suggest that that would result in sort of a measurable change and you're actually kind of dispersing the birds. Is that sort of misguided information? What's your thoughts on that?

Jennifer Ballard: Well, I think you're right that probably no one manipulation on the landscape is going to meaningfully change an outbreak, and there's kind of two ways to look at it. You know, flu, and actually Dr. Stalnick's done some great research on the way flu persists in water and at different temperatures. So, from that standpoint, I understand why people might want to dry out their fields, and that has been a recommendation in the past that's been used for Pasturella, but of course that's a bacteria and this is a virus, or avian cholera may be a more familiar term. But then again, dilution is the solution to pollution. So if you're mixing water and getting it out there, you might sort of, I guess, spread some of that around. But I don't think either way, whether you're talking about congregating the birds more or diluting the virus in the environment, I don't think you're going to be able to meaningfully break these cycles of transmission just by manipulating the landscape. So, yeah, that's kind of how I would think about it. This is a really broad landscape scale issue, and so the effects on one field or a handful of fields probably isn't going to change much. So, Dave, any thoughts on that?

Dave Stallknecht: I agree with Jen. I mean, you locate one water body that, you know, got some sick birds on, number one, you don't know that they were infected on that water body to begin with, and there's probably a hundred more out there that you haven't identified. So on a broad scale, you're probably not accomplishing a whole lot.

Mike Brasher: And so the other point to make here probably would be that history and evidence has shown that this virus goes through wild bird populations really, really fast, right? And so if I'm… Are we at a point where we're even starting to see symptomatic infection in places like Arkansas kind of begin to decline?

Jennifer Ballard: Well, we are getting fewer reports. It's really hard for us to know if that decline of reports is, you know, maybe fewer people were out or if they're just getting used to seeing it so they're not making the reports actively. Or maybe it is that we have fewer symptomatic cases out there on the landscape. And we also kind of see cycles that first we'll see waterfowl and then we'll start getting more reports in birds of prey that may have been consuming those waterfowl. So it's a little hard to say, but I do think, I would be curious what the other professionals on here think, but I think they do start to, if they're gonna die, they've probably already died and at some point they're moving into that stage where they're no longer actively infected.

Dave Stallknecht: Dave? We're always behind the timeline here. We're seeing the aftermath rather than seeing where it's going. One thing I do want to add to that is As far as getting rid of carcasses and that sort of thing, what a hunter can do to kind of help things a little bit, they need to be aware of how they discard viscera from even clinically normal birds, because that stuff is eaten rapidly by mammals and other birds and everything else. So, it's hard to dispose of that stuff, but if you can put it in a landfill, it'd be probably better than throwing it out in the marsh behind your blind.

Mike Brasher: What if you had just a small number of them, dig a hole in your backyard or back 40 or something?

Dave Stallknecht: Yeah, just don't throw it out. I mean, we've all done that in the past, and this stuff will infect raccoons and everything else pretty quickly. especially with viscera.

Richard Webby: Yep, and your daughter's pet cat too, so.

Mike Brasher: Or a cat. There have been reports of that, for sure, for sure. All right, so I think the last topic is, what have we learned? One of the common questions, Jen, that you were saying that you've received is, well, what about my dogs? The dogs are out retrieving the dead ducks, and obviously we know, encountering the virus in the water. So what do we know about the risk to dogs? Who wants to take that? Jen, I'll direct that to you, and then maybe Dave can chime in.

Jennifer Ballard: Yes. So there has been some work on that, and I think it's a super important question. As we've alluded to, other mammals have acquired these infections from mostly consuming, like the whole bird out in the wild, raccoons, bears, other species. So, in those species, there's a risk, and so that kind of would imply that there could be a risk to dogs, but so far that just hasn't been seen. And every species is going to have a different level of susceptibility. So what the research to date has shown on dogs is that dogs with a high level of exposure may seroconvert. And what we mean by that is they develop antibodies, they have enough exposure that their body gives off an immune response, but it doesn't necessarily mean that they've gotten sick or that they've shed the virus, but that they've had enough exposure to develop antibodies. So while I would not recommend feeding guts or anything from a duck directly to your pet, the risk seems to be really, really low. But also, I think, as we've talked about early on, there's a constant evolution of these viruses, and we don't want to tempt fate, especially with our canine friends. Dave, anything to add?

Dave Stallknecht: No, I think she summed it up really well. The risk seems to be really, really low. It doesn't mean they can't be infected. I think there was an actual case of a clinical case in Canada, I think. But I think that was a consumption thing there. You know, as far as just retrieving ducks, if you stay away from the neurologic ones in the field, I think he should be okay. Your dog should be okay.

Mike Brasher: All right. Well, we've covered a lot of ground here today. We've gone right about an hour and we covered some topics that we had not previously, which I always find interesting. And what I want to do is just a real quick around the horn to each of you, see if there's anything that we failed to cover that you wanted to make sure we did. Jen, I'll start with you.

Jennifer Ballard: Well, the veterinarian in me, I can't hold back. I would also point out that pigs are susceptible. So we've talked a lot about spillover into chickens. But people who may be raising swine should be equally vigilant about biosecurity and keeping that out of those facilities. And the last thing I would add on the dog front is if your dog has been out retrieving birds and possibly had these exposures, and then they start demonstrate signs of disease, be sure to take them into your veterinarian and let them know that they've had that exposure history, just like you would if you were going to the doctor. But I appreciate the opportunity to join you today. It's such a great and important topic.

Mike Brasher: Yeah, well, thank you for joining us, Jen. Dave, I'm going to go to you next.

Dave Stallknecht: I just got something simple. I think the audience needs to know that there's a lot to learn here. That's period. There's just a lot to learn. We don't have all the answers, but as hunters and wildlife biologists, you're part of the team, and you've been great help in the past, and I hope that continues.

Mike Brasher: Yeah. Well, Dave, we thank you for everything that you've done, and pleased to report that you made it through the episode without using any of your allotted four-letter words, so you can save those for a later episode. And Richard, I want to close out with you. It's human flu season right now, and so I know you are tremendously busy. Thank you for sharing your time on this. Any final words for our audience?

Richard Webby: No, nothing really of much intellect here, Mike. Just the same thing. This is a virus that doesn't like to infect humans, but we've seen a lot of animals that have been infected with this virus, including some humans. And the amount of this virus that grows in the brain is scary. So, when you're out there handling these birds, just keep that in mind. The risk is low, but the consequences of getting it can be pretty, pretty dire.

Mike Brasher: All right. Well, thanks to the three of you for your time, for your expertise, and for continuing to invest in helping us make better decisions and learn more about, as you said, this important virus, this important disease. So, thank you very much, and I'm sure we'll be in touch sometime in the future. We also thank our producer, Chris Isaac, for the great job he does with these episodes, and our newest helper, Rachel Bennett, for the tremendous work that I know she's going to be doing going forward. We thank you, the listener, for your time spending it with us, and as always, we thank you for your support of wetlands and waterfowl conservation.