2025 bird flu update: Trends, transmission, and economic impacts

[00:00:30]

ELENA RENKEN: Hi, everyone, and welcome to SciLine’s media briefing on the bird flu outbreak. Today, we’ll explore the evidence on some of the biological and economic questions surrounding the escalating disease spread and the circumstances that got us here. My name is Elena Renken, and I’m SciLine’s manager of journalism projects and multimedia. A little background about SciLine first. We’re an editorially independent, philanthropically funded nonprofit based at the American Association for the Advancement of Science and everything we do is free. Our mission is to make news relevant scientific evidence and expertise as accessible as possible for reporters like yourselves so that you can use it to strengthen your stories. At SciLine, we see every day how a dose of scientific context can enhance just about any story when you’re writing about something like the bird flu or a topic that might not seem connected to science at all like immigration or diversity initiatives. You can see all our resources on sciline.org including our toolkit for reporting on the major issues of 2025 and you can request an expert on deadline by clicking the blue “I need an expert” button. We hope you’ll call on us whenever we can lend a hand.

Now, before we begin, a quick note on logistics. We have three panelists with us today to give you context on the bird flu outbreak and each of them comes to this topic from a different scientific background. They’ll introduce themselves and their topics of research. But briefly, we have Dr. Carol Cardona of the University of Minnesota who will give some broad background about the bird flu, Dr. Maurice Pitesky of the University of California Davis who will cover how the bird flu is transmitted and how it spreads more widely, and Dr. Jada Thompson of the University of Arkansas who will give some more details on the economic impacts of the bird flu. I’m going to ask each of them a couple questions to start us off and then they’ll be taking your questions. Please feel free to submit your questions at any time here. You can just click Q&A icon at the bottom of your Zoom screen to add your question, and make sure to note if you’d like it directed to any specific speaker, plus a recording of this briefing will also be available on our website later today and a transcript will be added early next week.

And with that, let’s get started. Carol, would you introduce yourself including a few words about your research?

[00:02:54]

CAROL CARDONA: Sure. I’m Carol Cardona. I’m a veterinarian and have a Ph.D. in pathology. I’m here at the University of Minnesota where I serve as the Pomeroy chair in avian health. And my research these days—I’ve done a lot of different types of research, but these days I work on maintaining continuity of business. So, during a highly pathogenic avian influenza outbreak in poultry, when that happens in the United States, there are movement controls that help restrict movement so that the virus can’t leave the farm and all those other farms that are around it. So, my group does risk assessments to determine how movements can happen from the uninfected farms that surround an infected farm without spreading disease.

[00:03:49]

ELENA RENKEN: Great. Thank you. And I’ll first ask, “What is known about how far this outbreak has spread in both wild bird populations and commercial poultry operations?”

[00:04:00]

CAROL CARDONA: So, we know that this outbreak if we say that it started in 2022 in the United States that it has spread to all 50 states. If we go back further and ask when this particular strain of virus began to spread, it started spreading in 1996, and it has spread globally since then. So, we know that it has spread very far and very wide and we know that based on poultry infections, which sort of serve as sentinels. And we hear some about wild bird infections as well. But with 9,000 avian species worldwide, what we know about which species are involved, at a total level, we probably know only a smidgen of that. Primarily what we do know is that the virus now is endemic in some types of wild birds, mostly the anseriformes, so the ducks, the wild free-flying ducks that move through our country.

And so, we know that that’s partly how we keep getting these seasonal influenza outbreaks. And we know that a large number of mammalian species have also been infected and those mammalian species, how much we know about that, we probably know very little. So, there’s approximately 2,000 mammalian species in the U.S. and 3,000 avian species. So, of those 3,000, maybe we know a lot about 5 or 10. So, I think I think that tells you. And then, we sporadically know a few things about some of the others. And I think you’ll hear more from Dr. Pitesky on some of those ways that we can know and what we do know in different ways.

[00:06:06]

ELENA RENKEN: Excellent. Thank you. And what factors have led to this prolonged and worsening situation and why now?

[00:06:13]

CAROL CARDONA: So, the worsening situation in the United States, I mentioned this whole thing started in 1996. And there’s an excellent article which I can send you a link to from Les Sims who was the CVO or the chief veterinary officer in Hong Kong for many, many years. And he was the first to encounter this H5 influenza, and he was the one who eradicated it after eight people died after infection in Hong Kong in 1997. And so, he says that it has spread because it has spread through poultry systems throughout the world and I think we’re starting to see in other types of agriculture because there were options for things to do with infected poultry in many countries. So, if people had a choice, they did something else. I already mentioned movement is one way that influenza spreads. He also said that veterinarians were not trusted or there was a weak system. We’ve seen that time and time again. There’s an economic boom, then there’s often a growth that expands beyond the infrastructure to sort of monitor and control disease. We’ve seen that trade that doesn’t monitor H5 influenza is another way that this has spread globally. I think today we are dealing with the expansion in the United States is due to sort of these shifting interfaces. So, poultry flocks, poultry producers figure out how to protect themselves from one potential source and then a new potential source comes along for which they were not prepared. One example of that is of course the outbreak in cattle, which has created a new source that can get into their birds in a different way. We always struggle to prevent the wild bird-poultry interface. It’s very difficult to control all of those different species. And as I mentioned, we don’t necessarily know which species we need to exclude. So, while we know very certainly we have to exclude water foul, sometimes it’s very unclear if barns also need to exclude passerines or the little song birds.

[00:08:56]

ELENA RENKEN: Very good to know. Thank you. Are there any particular kinds of new sources that you’re talking about or perhaps species that you think reporters should be keeping an eye on right now?

[00:09:06]

CAROL CARDONA: So, I think we know very little about what’s happening with the peridomestic animals. So, skunks, raccoons, rabbits, they’ve all been experimentally shown to get H5 influenza and be able to transmit it. In addition, we’ve seen many, many cases in foxes around the country. And so, we’ve seen it in bears. We’ve seen it in all kinds of species. The things that I guess I’m most concerned about are some of these places and I think on the wildlife side we kind of have a good connection between agriculture and wildlife, but I think kind of we break down in terms of thinking about pet animals. And so, I’m very concerned about the situation in cats and that cats kind of go between sort of almost a feral state as they live on farms or interact on farms to a very domesticated and beloved house pet state. And so, the cat sort of infiltrates and can transmit between poultry flocks or cattle flocks that would have the infection and move it into human populations. So, I think that concerns me a great deal. I think the other one that concerns me of course are the infection of mice, which has happened recently. For many, many years, we thought mice were resistant to influenza because they have a specific genotype that a field mouse is prevented from getting infected in most cases. But now, we’ve seen H5 breaks all the rules, and so now it has been detected in mice on some infected cattle farms. So, I think that’s an important species because it simply infects everything in our human lives and can transmit to a variety of species.

[00:11:11]

ELENA RENKEN: That’s very useful to think about these other animals involved and perhaps some of the sources of data that we’re lacking.

[00:11:20]

ELENA RENKEN: Moving on to you, Maurice, would you introduce yourself?

[00:11:24]

MAURICE PITESKY: Great. Hi, everyone. My name is Maurice Pitesky. I’m an associate professor of cooperative extension at the UC Davis School of Veterinary Medicine. And my lab, among other things, we focus on remote sensing of wild water foul around the world and how we can use technology to make daily predictions and forecasted predictions about where wild birds primarily water foul like ducks and geese are relative to the tens of thousands of poultry, commercial swine and livestock facilities in the U.S., Canada and beyond.

[00:12:06]

ELENA RENKEN: Great. Thank you. So, how is bird flu transmitted and why is it spreading between wild birds and poultry as well as to other animals such as pigs and cattle?

[00:12:17]

MAURICE PITESKY: Yeah. So, as Dr. Cardona kind of alluded to, we don’t know a lot, but some of the things that we think we know are that wild water foul primarily migratory ducks and geese are the primary reservoir of this virus. And most water foul are migratory, so they can literally move thousands of miles every single year during fall and winter migration. And for example, I live in California in the Central Valley. And in that Central Valley of California, during the winter or late fall, we go from about 600,000 resident water foul to over 8 million water foul. So, right now, you drive anywhere in the Central Valley of California, you’re going to see ducks and geese. And unfortunately, where we have our dairy infrastructure and our poultry infrastructure, it overlaps spatially with where those water foul hang out during the fall and winter. And then when they move back up again in the spring, we get back down to that 600,000 or so number. So, if you have 1,000 dairies and you have 600 or so poultry facilities and you have 8 million water foul and they kind of spatially overlap with each other, that’s where diseases can be transmitted.

In California like the rest of the country and world to a certain extent, we’ve lost a lot of our natural wetlands. So, we’ve lost about 95% of our wetlands. That’s where ducks and geese spend 10 to 14 hours a day this time of year before they go on their feeding flights. So, they use what I call a suboptimal habitat, dairy lagoons, flooded rice fields, just ponding from rain. They’ll use that as their habitat. And unfortunately, a lot of that spatially overlaps with proximity to these farms. And then when these birds go on their feeding flights and things like that, you get aerosols that can be generated. Their habitat overlaps with some other wild animals, so you can get what we call mechanical transmissions. So, the poop which might have virus and other diseases on it can be mechanically transmitted on the feet of rodents, for example, we think and then transmitted into these barns. So, from the way I kind of look at this from a big picture transmission perspective, it’s that kind of confluence and overlapping of wild animals and domesticated farm animals that has created a higher probability of transmission. It’s not the only way the virus is transmitted, but it certainly makes it a riskier kind of scenario.

[00:15:05]

ELENA RENKEN: Thank you. And what types of biosecurity measures have been effective at curbing outbreaks or spread between wild and farm populations in the past and which are in place today?

[00:15:15]

MAURICE PITESKY: Yeah. So, there’s kind of like a whole smorgasbord of different types of farms, organic or conventional, layer and broiler facilities, the places where you and I might get our eggs or our meat from. They have different ventilation systems. So, there’s a lot of different variables there. For the data that I’ve looked at for specific companies and if you look at the USDA’s 2022 high path AI interim report, the primary risk within a 20-day window of farms that break with high path AI are facilities that have I’ll just call it high water foul abundance, high amounts of ducks and geese within about four kilometers of that facility.

Now, that makes sense especially when you overlay where we’re finding high path AI detections. So, we look at the water foul in that 4 kilometer area. We look at when high path AI is detected and we do some disease modeling. And if you take that variable and then you also take other variables related to kind of on-farm biosecurity, so things like ventilation systems, things like without getting into all the details whether the farm or barn has what we call curtains. So, curtains are these things that go up and down on the long axis of these barns, which can be several hundred yards long. Those are the kinds of variables that you can combine those together and really identify what variables are the most predictive when it comes to what I call outward-facing biosecurity and inward-facing biosecurity. And I think just from a holistic perspective, about 99% of the research and effort that the poultry industry has made and academics have made on protecting poultry is really what’s going on inside those walls, what we call operational and physical biosecurity, and what I’m trying to do is integrate that with what’s going on outside the facility with respect to the water foul that might be roosting around one farm one day and then might be roosting around a different farm the next day based upon all kinds of environmental predictors.

[00:17:46]

ELENA RENKEN: Very good to know. Thank you. And Jada, could you introduce yourself?

[00:17:51]

JADA THOMPSON: Yeah. Hi, I’m Dr. Jada Thompson, associate professor of agricultural economics and agribusiness at the University of Arkansas division of agriculture. I predominantly study animal health economics with an emphasis on poultry and poultry production systems. And so, HPAI and bird flu in birds has been a big form of research in my studies recently.

[00:18:16]

ELENA RENKEN: Great. Thank you. How can disasters like these animal disease outbreaks impact food production systems and can they ultimately impact prices at the grocery store?

[00:18:27]

JADA THOMPSON: Can they? I think this is the biggest question I’ve been asked recently. Of course they can. I think that this is the question for why are egg prices high. Big large-scale animal outbreaks are going to impact what kind of foods we’re eating. So, if you’re talking about a layer system, this is going to impact the birds that are laying the eggs. Well, if there’s no birds to lay eggs, there no eggs to have, and then we have a supply shortage, and that leads to higher prices because of supply and demand dynamics. If we talk about the cost in the system, so it’s not just those layers, it’s also the breeding system, so that prolongs the cost of the disease outbreak and prolongs the replenishment of that system. And so, when we start talking about the disease outbreak, it’s not even just the direct impact and the biological lag to replenishment, but it’s also the multiplicative impact in terms of further upstream on that system.

[00:19:20]

ELENA RENKEN: Good to know. Thank you. And I think you started talking about this a little bit, but could you tell us more about other economic costs associated with disease outbreaks like those incurred by livestock and poultry producers as they pay for these new flocks and biosecurity measures?

[00:19:34]

JADA THOMPSON: Yeah. So, I think that when we start thinking about the cost of disease outbreak, I’m a consumer. We’re all consumers first and foremost, even those producers. And so, I think we think of the retail prices. So, obviously, we see the changes in retail prices for my eggs at the grocery store. I see the changes in my chicken prices or turkey or milk or whatever the case is. But there’s also the cost of the biosecurity that Dr. Pitesky was talking about, just these practices that have to go into place, and those are additional costs. There’s additional cost for the monitoring and surveillance, for the cleaning and disinfections. There’s additional cost for the testing, and that’s going to be to the producer, to the integrator, to the government officials, to the testing labs. There’s also time and effort involved in all of these different situations. And then also, us as a consumer where we’re having to process our risk perceptions of those types of foods. And so, the costs aren’t just the direct ones that we can see. And so, when we start thinking about how those affect the entire supply chain, they are all up and down the supply chain and they’re multiplicative along the line.

[00:20:36]

ELENA RENKEN: Very good to know. And is there any way you’d suggest that reporters could start to quantify some of these costs or is it at too grand a scale?

[00:20:45]

JADA THOMPSON: I think you’re talking a pretty grand scale. But if you do, I have an economics lab. You can come work for me. I’d be happy to pay you some money to start analyzing this. No, I think at the end of the day, I think we can talk about any one of these pieces I think to start to quantify the entire cost. It’s a pretty large-scale effort, and not all the data is public. So, I don’t know everybody’s private costs. I don’t know all those biosecurity costs that the farmer is adopting. I know that there is a lot of biosecurity costs, and I know that over the past 15 years there’s been a lot of investment in biosecurity. And so, are we counting all of that to be part of this outbreak? And so, you start thinking about where’s the cutoff points. And so, I think that that’s why it’s a bit of a moving target in terms of the total cost. I think we can use what USDA reports as the government cost and say that this is the largest cost. I think we can talk about what the consumer cost is and there’s some papers. I did one with Dr. [James] Mitchell and Trey Malone where we looked at kind of the cost to consumers and the cost to producers for this outbreak without even accounting for those private costs and so just in terms of welfare.

[00:21:46]

ELENA RENKEN: Definitely a lot of different cost to factor into reporting there. Thank you.

[00:21:51]

ELENA RENKEN: So, as we turn to questions for all three of the scientists with us, I want to remind reporters on the line to submit their questions using the Q&A box found at the bottom of your Zoom screen. And for our first question to all three of you, I want to ask you about the news coverage you’ve been seeing on the bird flu. What are reporters doing well and what could they be doing better? Anyone want to take that one first?

[00:22:12]

CAROL CARDONA: I’ll kick it off. My favorite pet issue with this has been people calling this bird flu or high path AI when they’re talking about other species beyond poultry or beyond birds. That’s just absolutely wrong. It should be H5 influenza in and then you’d name the species. It will become very, very confusing for readers as you start to talk about bird flu and then you’re looking at a dog. I think also people do a sort of a little risk assessment in their head thinking, “How do I not get this bird flu? Well, I’m going to stay away from birds.” And that may not be their primary risk factor. So, I think it’s important to kind of get it right and maybe the horse is out of the barn, but I still think it needs to be changed. I think though some of the things that reporters are doing very well, I think there’s been some excellent reporting on some of the political aspects of this outbreak that have become involved. It’s very, very complicated, and reporters are very much engaged in trying to capture a holistic understanding of this outbreak as opposed to just sort of taking snippets. So, I really admire that and I think they’re doing that well.

[00:23:51]

MAURICE PITESKY: I guess I can go next. So, I think reporters are doing a good job in the sense that I’m getting texts and emails and phone calls pretty consistently and people are just asking questions, so I think that’s really good. There’s that curiosity there and that’s how you start digging down a little. You start asking more and more questions and understand kind of what we’re dealing with, which is unprecedented at this point. I think where we probably need a little more help is just on the connecting of the dots. So, I’m an epidemiologist. I look at a lot of data. And the information networks that we have between the farms and the state and feds are not really very robust. So, we’re not getting information that is being shared with researchers. Farmers don’t have information as far as what areas and geographies and times that farms might have higher than normal risk and lower than normal risk. So, that ability to transmit data and share all the data that’s being captured is really being siloed and not shared, and that’s to the detriment I think of everyone, and I don’t know if that story’s really been told very well yet.

[00:25:16]

JADA THOMPSON: I’ve been getting all the questions about the about the costs and about why egg prices and I think for the most part there’s been really great coverage and understanding or explanation of that from a supply and demands structure and talking about understanding the mechanism for why prices and why we see them. I think sometimes we want the quick answer of when is it going to go away and how can we move on to the next story, and I think this is one of those cases where it’s not fast. Prices aren’t going to recover tomorrow, but they will recover. And so, at what point. So, sometimes, I think we don’t want to make an alarmist thing, but we also need to be clear that things are not going to change overnight and so tomorrow the same issue is going to happen. And so, some of that, that these issues are going to be ongoing until this disease is controlled or until we figure out how to best mitigate the longstanding implications of it.

[00:26:12]

ELENA RENKEN: Really useful insights. Thank you. For our first question from the audience, I’d like to ask, “Are other affected countries taking steps to contain the disease that we can learn from?” Maurice, maybe that’s one you could start on?

[00:26:28]

MAURICE PITESKY: Yeah. So, because of the work I do, I’ve been zigzagging a little all over the world trying to create kind of a global surveillance system. So, there’s a lot of different approaches. Other parts of the world are vaccinating. There’s some success there. Dr. Cardona could probably speak better on that because I’m not an expert in vaccines. There’s challenges with vaccines. I think it’s not a panacea, but that’s definitely a huge kind of difference in how we respond versus how other countries respond. I think as far as kind of data goes, that’s an area that we all have some problems with. We don’t share data very effectively. And ultimately, what’s going on in Southeast Asia, what’s going on in the Middle East, what’s going on on the continent of Europe, those detections matter for us from a surveillance perspective and vice versa. So, we need to move toward sharing these type of data through the government organizations we have. And even at a continental level, we don’t really share. When I look at a USDA map and I look at a Canadian Food Inspection Agency map, that geopolitical border is basically where our surveillance stops and where their surveillance starts and there’s no connectivity between those two. So, we’re having a lot of siloing going on. But the biggest difference and I’ll defer to Dr. Cardona on it is kind of the utilization of vaccines and the efficacy of those, which is still being studied I think.

[00:28:16]

ELENA RENKEN: That was the next question we had actually about whether vaccination of poultry flocks is a feasible response to the spread of the disease. Carol, would you like to weigh in on that?

[00:28:25]

CAROL CARDONA: Sure. I have a lot of opinions on this one. So, vaccines are something that in the United States we said back in the I think it was the ’70s or ’80s that we wouldn’t vaccinate for highly pathogenic avian influenza and we wouldn’t trade with countries that did vaccinate for high path AI. The reason is that at that time we had very limited veterinary infrastructure, very limited lab testing capabilities. We had like Maurice was talking about very little information about disease systems and much less knowledge about the types of surveillance you would need to do to assure yourself that you weren’t importing high path AI along with an immunized bird. An immunized bird can harbor the virus to some degree and be protected from clinical signs, in other words, not die. So, it could be imported either in the products of immunized birds or in the birds themselves. And so, at that time, that was true. Today, we are a very, very different country. And so, we’ve held on to that sort of protectionist ideology and we don’t allow immunization in the United States. A lot of it is due to in poultry we have three major species, turkeys, layers and broilers. Broilers represent 96% of the industry. And so, that 96% says, “No way are we going to vaccinate because we are going to lose a lot of trade.” Turkeys and layers are kind of interested in figuring out immunization because they’ve been harder hit and they don’t have as much trade.

So, I think here’s a place where we’re seeing that now France is immunizing and just a month ago or last month the United States opened up trade for nonvaccinated poultry and poultry products from France, but we had had an embargo before that. And so, we’re often the first to cast that political stone and pull out of trade agreements. So, I think it’s a matter of revisiting those trade agreements and having to understand that the entire globe has H5 except New Zealand. I think that’s all now. And so, if that’s the case, we have to all come together to fight this virus. It’s not just one country that we’re protecting ourselves from or their poultry products. Everybody has it. So, I’m not sure what kind of all of the nuances are about. And I’m I know I’m being overly simplistic here. But as a veterinarian, it’s very important in my mind that this is a tool that can be used to protect birds, to protect humans from spillover cases, to protect cattle, to end the overt outbreaks and the epidemics in these species. It can be done with immunization. So, I’m very pro immunization, and that’s why we don’t do it is trade.

[00:32:16]

JADA THOMPSON: Do you mind if I chime in here and add a little additional economic context to this? And so, I think vaccines are definitely a great solution, and I think Dr. Cardona brought up a lot of really great points. One of the concerns with vaccinations are those three industries and you have the broilers who are younger who aren’t infected and you have some a bit of geography kind of insulating them a bit. And so, the concern is I think that you’re having to work with trade partners. So, it’s not so much U.S. banning trade as much as other countries banning our trade. And so, if 16 to 20% of your products which are broilers are exported, then that’s a pretty large market and I want to protect that. And so, the question has been, “Can we have a vaccination strategy where we just vaccinate layers and turkeys won’t be as impacted and then broilers stay unvaccinated?” And so, I think that there’s a lot of research going on right now to look at different vaccination strategies and how those would impact the market place and also thinking about trade partners. And so, this is going to be the trade organizations that are working between the U.S. and these other countries to accept those products. And so, is France going to accept those products? Because if they are, well then we can have a different strategy.

And so, I think that there’s a renegotiation of trade relationships happening right now and thinking about the acceptance of vaccinated products. From the U.S. perspective, I think the concern is also how consumers are responding to that. So, you have a lot of consumer acceptability of vaccinated products and they’re already vaccinated for other things, but I think the question is, “Are consumers going to accept this product?” And I think those are questions that you need to ask before you roll out the strategy because there’s an economic cost to this. And so, we have to think about all of those components and, I think that that’s adding the nuance to those conversations. So, not just control and eradication, but also the value of the product that you’re selling.

[00:34:05]

ELENA RENKEN: Great. Thank you. We have several questions from reporters right now about any threat posed to human health right now by the disease. So, could anyone comment on that? Anything we can expect going forward? Including when it might make sense to begin vaccinating humans, if ever.

[00:34:28]

CAROL CARDONA: So, I can take that I guess. So, let’s start with the human immunization and the human sort of threat. There’s a tool that the CDC uses called the influenza risk assessment tool, and it’s a very nice tool. So, if we look at H5 in general, the tool looks at the risk or the changes in the virus. The B3.13 virus has been evaluated and it’s known for example to bind to both human and avian type receptors, so it’s considered a broad threat. The current D strains of the virus appear to be able to bind to the human or the mammalian type receptors and so therefore creating a different type of threat. But globally speaking, H5 influenza has already shown its ugly head as having the ability to either be a human infectious virus, but not yet shown to transmit between humans. It has in some instances been shown to transmit via droplets and through airborne means among animal models. Both the 3.13 virus, which is the virus in cattle, and other strains of the virus, it was shown to transmit tiger to tiger in Thailand when they got it. So, it has its abilities and it seems very ready to move in that direction.

Another part of the tool looks at the host. And so, as a human threat, we have a very unprotected host. I think we have probably 67 people now in the U.S. that have immunity to H5 because they’ve been infected. The rest of us don’t. So, I think it’s important to understand that in large part we’re an unprotected population. Another aspect of the tool is to look at the ecology. So, some of that would be what animals as I was alluding to are getting close to us, how much transmission are we seeing and how many spillovers are we seeing, how many human cases. And we’re starting to see more. The subclade virus 2.3.4.4b globally has dramatically increased the number of human infections. And so, the spillovers of course are what we fear could someday lead to a human-to-human transmission, but we haven’t seen that yet. So, I think that influenza research assessment tool is a very valuable thing. I think it’s Sue Trock, 2015, published that, but let’s see. What was the other one? Finland is vaccinating for H5. We’ve started in the U.S. manufacturing vaccines. The good news for humans is there’s been some Tamiflu resistance demonstrated in some genetic signatures, but it’s been in only one strain of virus. It has not been very widespread. It’s been a single case. And we do have the recent tests of the virus strains that are stockpiled are a good match to the current strain. So, we have a lot of the tools in place to really respond if this becomes a bigger human issue.

[00:38:17]

ELENA RENKEN: And is there any particular sign or signal people can look for in terms of when this is a larger human issue and vaccinations for humans should be considered?

[00:38:28]

CAROL CARDONA: I think it’s human-to-human transmission or sustained transmission in animal models and the influenza risk assessment tool also evaluates impact. So, people complained a lot about in 2009 that it didn’t have a lot of impact because it wasn’t super clinical, but the risk assessment tool evaluates not only transmissibility, but also impact. So, right now, we have two strains that have gotten into humans and one of them has caused more severe illness. So, the suspicion is if that were to become a pandemic strain, we would see big impacts, but the B3.13 virus has shown conjunctivitis. And so, it would have a lower impact, but could still cause a pandemic.

[00:39:30]

MAURICE PITESKY: Can I just chime in for one second too? So, I should also point out that the biggest occupational risk right now is for dairy workers in milking parlors and also poultry workers, anyone around those two animals specifically. And one of the real challenges especially in agriculture is you have a lot of workers that are undocumented, so they’re not in any surveillance system at all. There’s no outreach to get them vaccinated against human influenzas, so what we don’t want are co-infections with all kinds of different influenzas in humans because that’s how bad things also happen. So, one of the worst case scenarios is because we don’t have good surveillance and good access to a lot of these dairy workers and poultry workers as far as public health is you’re going to get an outbreak that happens and starts building especially because a lot of these workers live in multigenerational multifamilial homes and the virus can spread really quickly in those environments and spread even further before any kind of detection is made. So, we need much more robust surveillance and much more robust public health and access to the workers on those facilities in my opinion.

[00:40:46]

ELENA RENKEN: Thank you. That’s very good for reporters to keep in mind, those high-risk populations like undocumented populations in the U.S. I wanted to take a moment to mention that this briefing is on the record. So, reporters, please feel free to use quotes and footage from this briefing in your stories and your segments. That is all available to you.

[00:41:08]

ELENA RENKEN: Next, I wanted to ask about indications that the Trump administration’s halt of CDC publications is actually interfering with the response to avian influenza. Could anyone talk a little bit about the role that the CDC plays in tracking and combating diseases like this?

[00:41:33]

CAROL CARDONA: So, I think that the CDC has been our premier epidemiology force out there. And so, it’s important to get that information that they can provide. To Dr. Pitesky’s point though, we do have some holes and the CDC hasn’t been able to break down all of the barriers that have existed, for example, in doing the human surveillance around cattle cases. So, until influenza got to California, you saw a different picture. You saw that there were more human cases associated with poultry workers depopulating poultry flocks because we had such underreporting of bovine cases in so many places. And then, we had the natural lack of reporting of sort of this mild eye soreness that people kind of felt associated with that. So, it’s a difficult situation. So, the CDC leads our surveillance efforts, but they’re certainly not the only surveillance mechanism. And I think it’s important for—Dr. Pitesky also talked about local differences. And if you look at the whole country, the CDC is going to be working with state public health units and leading them, providing guidance documents, but also leveraging the state resources. So, the CDC is critically important, but not the only one out there.

[00:43:28]

ELENA RENKEN: Thank you. And next, I wanted to ask, “Are some regions of the U.S. more susceptible to this disease appearing in livestock? And what factors influence this like climate or types of agriculture?”

[00:43:41]

MAURICE PITESKY: So, I can take a small crack at that one. So, in general, there are geographies and time periods where farms have more water foul surrounding them, for example. So, there are risks. One of the things I have to remind farmers is that the farm might not change location, but the risk will change. So, that’s a really important reminder. And because of climactic change, because of land displacement and things like that, the risk changes every year. So, it’s really important to kind of understand location matters and every year and month and day is a little different than the last year. So, there are some facilities that are going to be a greater risk. We’ve had some facilities that have broken two and three times and have lost a million birds each time. That’s a real problem, and we have to make some decisions about those locations and what kind of mitigations and/or changes we need to make with putting facilities in some of these high-risk geographies and locations. The other thing I’ll mention on the dairy side, it’s much more complicated as far as how the virus is moving. So, coming from California, we’re a very large dairy state as many of you know. The virus doesn’t seem to be—without going into all the details, we think the virus is moving from facility to facility not via wild animals, but through biosecurity practices and normal trade and husbandry amongst dairy facilities. That would explain it at some level. Unfortunately, that probably explains how the virus moved from a dairy in Texas to I think we’re up to 15 or 16 states at this point. And in California, it’s had a devastating impact how it’s moving between dairies. That’s most likely not through wild animal transmission. That’s just through normal kind of husbandry practices associated with the dairy industry. So, there’s a lot of different moving parts here. Sometimes, it’s more of a human kind of production type disease transmission route. And sometimes, there’s some wild animals involved. And sometimes, it’s a mixture of the two.

[00:46:10]

JADA THOMPSON: I also think just to the regionalization that you talked about that part of the regionalization is that concentration of production that happens in different regions in the U.S. And so, we’re going to have a lot more eggs being talked about in the Midwest because that’s where a lot more eggs are being produced. And so, you have a lot more chances for egg layers to be impacted in that area. And so, we can kind of think about not even just the disease itself, which it does move and it has all these other mechanisms that the other two folks have talked about, but also like the regionalization. So, from a management standpoint, there are decisions that are being made for regionalization and concentration or efficiencies of scale that also has a downside as well.

[00:46:46]

CAROL CARDONA: And I think we’ve always thought over the years that most of us fluologists I guess think about arctic rain. And so, we always talk about the arctic rain hypothesis, which is that as birds fly south they simply have fewer flu viruses. And most of us who’ve done top to bottom type of sampling along flyways will tell you that the birds at the top of the flyway, the migratory birds at the top of the flyway are shedding more than the birds at the bottom probably because they develop antibodies over the course of their flight, which takes time. And by the end of their flight, they’re not shedding very many viruses. So, we’ve seen in these outbreaks if you simply divide up the premises, you will see that 90% of the cases are across the northern part of the U.S., 10% across the bottom. Some of that is due to species susceptibility with boilers being less susceptible than turkeys, for example, but a lot of it also has to do with some of this exposure.

[00:48:01]

ELENA RENKEN: Excellent context. Thanks to all of you. I next wanted to ask about questions reporters might use in the course of their journalism. So, when you’re reporting on this disease locally, what questions would you recommend asking local farmers about their precautionary measures or what questions would you recommend asking local public health officials?

[00:48:20]

MAURICE PITESKY: I think for farmers it’s a good question to ask what help they need. So, it’s my opinion that farmers need a lot of help right now. That’s nothing against farmers. It’s just that we’re dealing with something historic and that farmers, it’s very hard for them just because margins are narrow and they’re working insane hours and stressed and all the things that farmers go through, but this is way beyond the scope of farmers. And to that point, it’s way beyond the scope of many of the state and federal departments of ag. We just don’t have the right skill sets in place. We don’t have the right information networks. We’re not training at some level our veterinarians to really think about these problems holistically. So, I think to your point, farmers probably just need more help on the technology side and things like that I think at some level. And I think from a public health perspective, I think public health officials need to be able to get access to farm workers. So, from the epidemiological kind of human pandemic issue, that’s the tip of the spear. We’re not getting access to those workers. I know that from talking to folks in public health in California, and that’s a real challenge. So, someone’s going to have to start figuring out how to get into those facilities and do surveillance. They’re just starting to do surveillance of like dairy veterinarians and things like that, but the people that are in those milking parlors, the people that are in those poultry houses every day, we don’t have good access to them and from a public health perspective that’s not a good thing obviously.

[00:50:12]

ELENA RENKEN: Any other questions local reporters should have in their back pockets here?

[00:50:17]

CAROL CARDONA: Well, I think you need to—just to add on to what Maurice just said, I think you need to understand what farmers are kind of feeling right now because if you were to come to a Minnesota poultry producer who’s been through 10 years of this and people saying, “Well, you just need to have biosecurity, come on, now, you just need to do biosecurity,” what exactly am I not doing? That’s what they’re going to say. And if you were to ask them what biosecurity they have, you have to also tell them what the source is and what to prevent, what to do better. There’s very little information about that. In 2015, we learned that having your garbage next to your poultry house was a significant risk factor. Everybody moved their garbage immediately. We haven’t had those kinds of risk assessments since then. We’ve had a few that say there’s wild birds in your area as Dr. Pitesky said. How could we change that? There’s nothing you can do. So, I think the point is that I think you need to ask them perhaps open-ended questions. We hear the poultry folks are very angry about bovine outbreaks. They’re very understanding of the difficulties those farmers are facing, but they’re very angry about—dairies have to do very little to control the disease in them, but poultry folks, you need to have more biosecurity to prevent getting it from those dairies that you’re next to. As Dr. Thompson mentioned, that costs money. So, they’re angry. And I think asking them open-ended questions and listening is going to get you a long way with them.

[00:52:32]

JADA THOMPSON: I’m going to add to that that biosecurity is a weaker link public good, which means that the weakest link is where disease gets in. So, we start thinking about this idea of I can’t invest as much as a very rich farm. So, I can do as much as I can, but that also means that maybe I’m not able to do everything. And so, potentially, I’m a route for disease transmission. And so, I think that that’s a little bit of the question coming from this conflict happening between dairies and poultry right now is who needs to invest in what investments and for what costs because they have two different parameters where the cows aren’t dying from the disease. They’re getting sick. They’re losing milk, so losing efficiency, so you’re losing hitting your bottom line, but you’re not losing an entire herd. And so, I think that there’s a lot of nuances in thinking about how production systems are working. And so, when you’re talking to producers or if you’re talking to a grower and talking about influenza virus and thinking about how those production systems are working and how the virus is affecting those production systems because we’re not talking to dairies about losing your whole herd. We’re talking to dairies about how are you losing some milk. When we’re talking to a layer facility, you’re going to be depopulated because you’re also going to lose all those birds either way. Those birds are going to die because it’s highly pathogenic. You’re going to have high mortality rates. And so, I think those are conversations that reporters might want to keep in mind.

[00:54:01]

ELENA RENKEN: Definitely. Thank you. I appreciate you all bringing up those information gaps and some of those mortality rates. Those are good things to have on mind. A question for Jada. I know we’ve mentioned all the different costs that contribute to the overarching costs of this outbreak, so I know it’s hard to calculate, but do you have any sort of ballpark figure of the cost to the U.S. food system at this point or anything that we could compare it to in reporting to help put it into context for readers?

[00:54:29]

JADA THOMPSON: So, I don’t have a current to date cost. I did a paper I alluded to earlier where—so, I did a paper where we looked at the cost to consumers of consumer welfare. So, for 2022, we estimated about a $690 million cost to consumers, that that was a loss that they had in terms of having to pay higher cost. So, higher prices at the grocery store for eggs. Now, 2023 wasn’t the same outbreak as ’24 and we haven’t updated that analysis to look up to current day. So, I can tell you that roughly in 2023, there were government costs and for consumers we estimated about 690 million for that year. And so, you’re talking about costs getting into a billion dollars and plus would be a very I think a strong estimate of that. Nobody’s going to have an actual number for you. A lot of those costs aren’t public. A lot of those are private costs or are just not available to the public. So, that’s my best estimate.

[00:55:33]

ELENA RENKEN: Very helpful. Thank you. And I’m going to try to squeeze in a couple more questions before we wrap up here. So, first, what vectors of transmission from animals to humans have occurred so far and can we expect that to change now that there are more possible points of transmission from animals to humans?

[00:55:53]

CAROL CARDONA: So, transmission is primarily of influenza viruses, although we talk a lot about the importance of droplet transmission between humans. Really, when we’re talking about going between animal species and especially between sort of flocks and stuff, it’s really a fecal oral type transmission or a fomite transmission. So, you’ve got to be in contact with secretions from that animal source and get it into your eyes or your mouth or your nasal passages. And so, the human transmission piece, because we haven’t seen that droplet transmission, it’s not just being in a room. It’s usually going to be some sort of poking your eye. So, when you think about poultry workers who are depopulating, they’re in heavy PPE and I can tell you you’re going to sweat like a pig in those things, although pigs don’t sweat, but you’re going to sweat like heck in those things. And a lot of times, my thought and I don’t know that people have published on this, but my thought is I’d be wiping my eyes because those goggles fog up even if you have the anti-fogging type and stuff. And so, I think it’s matter of self-inoculation early on and that’s what we’re seeing. When we talk about cats in homes being infected, I think there’s a lot of crossover between human and cat secretions and fecal matter and all that stuff in homes. And so, I think that’s how the transmission happens. If the virus were to gain the ability to be droplet transmitted more readily between, it’s going to be between hosts of like species because that’s who you get close to. You’re going to kiss your kid or you’re going to cough in the face of like species or things that you live with as opposed to you’re not necessarily going to cough in the face of a cow. So, I think that’s the transmission piece of it. Did that answer the question?

[00:58:17]

ELENA RENKEN: Yes, thank you.

[00:58:18]

MAURICE PITESKY: One thing I’ll add just really, really quickly is just to show you how complex this is. So, back in 2021, I made a disease model along with some colleagues about how the virus we predicted it was going to spread. And I believe the word that I used when I was talking to the poultry industry was that we were going to get hammered. And I’ve had people ask me since like, “Can you make some more of those disease models so we can see what’s going to happen next?” And I’m like, “No, because it is so ubiquitous in so many different environments and species, wild and domestic, different environments, wastewater lagoons, that you can’t model that. It’s too complex.” So, just to kind of add on to where we’re going, I don’t think anyone knows where we’re going other than the virus is pretty ubiquitous. It’s endemic at this point, and we’re dealing with something we’ve never dealt with before.

[00:59:12]

ELENA RENKEN: That’s a very good cautionary note to end on. Thank you. I do want to mention before our final question where our speakers will give some kind of final takeaways from this briefing that after this closes out, reporters on the line, you will be getting a brief survey from us and we would really appreciate if you just take 30 seconds to give us any insight you have on whether this format is useful for you or how we can make these briefings as helpful as possible. And with that, I want to ask our final question for our panelists here. In about 30 seconds, what is one key take-home message for reporters covering the bird flu?

[00:59:54]

CAROL CARDONA: I’ll say H5 influenza isn’t going away. We are going to have changes in how we raise animals and how we do things because this virus will become endemic and it will continue to be a scourge. And my big thing is I think that disease control should be separated from trade because I think they’re separate issues and we shouldn’t be able to choose trade over disease control or the health of humans and animals.

[01:00:27]

MAURICE PITESKY: And I’ll just say I guess for the third or fourth time farmers need help, we’re dealing something unprecedented, and that there are no short-term solutions. We need to think medium to long term at this point. And I think ultimately we really need to think strategically for the first time about where we have our animal agricultural facilities relative to habitat for wildlife.

[01:00:59]

JADA THOMPSON: The key takeaway would be that prices are going to be impacted because of birds being taken out of the system. We’re going to see those ebbs and flows as commodity prices go up and down related to supply, but that the supply you are consuming should be safe and healthy to consume, that eggs in the marketplace aren’t coming from diseased animals, that if you cook your meat to safe levels I think all the reports show that it’s going to kill the virus. And so, our food supply is still healthy. Our prices might be high, but they should come down when supplies come back on, and that everybody is working as hard as they can to try to mitigate this disease as well as they can and as quick as they can.

[01:01:39]

ELENA RENKEN: Thank you. I want to thank our three panelists for being so generous with their expertise and time today. And a big thank you to all the reporters who showed up to gather more of the evidence on this ongoing story. We really appreciate everything you’re doing to inform your audience as well, and we hope we’ll see you at the next SciLine media briefing. Thanks.