The avian flu virus continues to affect poultry producers and dairy farms in 2025. In North Carolina alone, the virus has resulted in the loss of millions of birds on poultry farms. Meanwhile, less than a year after avian flu was first detected in dairy herds, a new strain of the virus has been found in Nevada cows.
To make sense of the latest developments, we consulted Matt Koci, a virus expert and professor with NC State University's Prestage Department of Poultry Science, who keeps a close eye on avian flu.
What are the latest developments with avian flu in poultry?
The big change, which has been true for the last couple of years now, is that avian flu is sort of here to stay, and it's become more of an ever-present threat and danger to poultry. That danger increases at different times of the year, but it doesn't go back to zero like it used to. Avian flu outbreaks may be associated with migratory patterns in birds, but now the virus seems to be established in wild birds that live in the U.S., including North Carolina. There were reports just last week of a great horned owl in Wake County found dead with bird flu. There's a greater risk year-round that it's going to end up in a poultry house because it's in wild birds locally, not just birds that happen to be transiting through during migration season. That's different from what we saw in 2015 and even 2021 when outbreaks happened, but after bird migration, cases would go away and things would go back to normal. Around 2022, avian flu cases decreased but never went away in all of the states.
The poultry industry is adapting to the evolving threat. But until just recently, what we always told poultry producers and farmers and the public was that avian flu was going to get introduced through migratory waterfowl - ducks, geese and other birds as they flew over. And so biosecurity and what people did to keep wild birds away from poultry focused on migratory waterfowl. Now that avian flu is in local wild birds, there may be more birds that farmers need to be aware of. The way H5N1 may get into a poultry house is probably changing, and so farmers are having to adapt to that as well.
How has highly pathogenic avian flu or HPAI affected the poultry industry so far in 2025?
On the laying hen side alone, we've lost over 3.3 million birds in North Carolina since the start of 2025. In just the last 30 days the United States lost around 20 million birds, with over 18 million of those being laying hens, which is roughly 5% of all the laying hens that we typically have, which of course affects the supply and price of table eggs. To replace those laying hens, it takes about 20 weeks to hatch out the chickens and then for the hens to reach maturity for egg production. But you also have to keep in mind that it takes time to clean up each farm following an outbreak. So, each of those farms will likely be out of production for at least two to three months. Replacing 18 million birds is going to take time, and all the while bird flu is still around, so we're still losing birds at the same time.
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Is avian flu evolving in dairy cows as well? There's been some recent news about a second strain found in dairy cows in Nevada.
What's in dairy cows in Nevada now is still H5N1 avian flu, but it followed a different evolutionary path through wild birds. Both the new strain of H5N1 that's been detected and the one that's been in dairy cows for a while are related, but they've evolved a little bit differently. For the longest time there was really only one strain of bird flu that we were finding in cows, and the cases seemed to all be linked to each other. The thought was, there was one introduction into cows in the Southwest and all the other cases were related.
This new case suggests that the virus has jumped from birds to cows a second time, and so this case isn't related to the others. We know that because genetically the H5N1 strains in dairy cows have some distinct differences. They're still H5N1, but it's kind of like the difference between omicron and delta in the COVID-19 virus. We know they were both SARS-CoV-2, but they were different, and this is sort of the same situation.
What's the significance of finding a new strain of H5N1 in dairy cows? Should we be concerned?
It's difficult to draw any big conclusions about what that means. By no means is that proof that the virus has evolved in a way where it's getting better at infecting mammals. It does have a mutation we generally think helps with infecting mammals, but it only has one of these, and one isn't enough to really be better. It's not good news, but there's no reason to think it's worse news than what we're already dealing with. It probably just means that whatever unique set of circumstances happened in Texas happened again with a different, closely related virus.
We don't know exactly how these Nevada cows with the new strain of H5N1 got infected. We're still not a hundred percent clear how the original cows in Texas were infected. The strain found in Nevada cows is a better match for what we're finding in wild birds scattered across North America - more so than what we've seen in the cows before.
From a prevention perspective, what are scientists doing to prepare in case this virus spreads more widely?
Every lab that's already been engaged in bird flu research is all-in, working as hard as they can. Because of how deadly bird flu is for poultry, you have to have a specific kind of laboratory with specific biosecurity to be able to work on bird flu and understand how it might be changing. Not a lot of labs in the U.S. are built to provide the level of biocontainment required to do those kinds of experiments. And unfortunately, that includes NC State. So there's a bottleneck there. A lot of poultry companies and now dairy companies have a lot of questions, but there are not enough labs able to do the research to answer the questions as fast as they are coming in.
We've been preparing for a bird flu outbreak for some time. We've done tabletop exercises. The government has put lots of resources into it, including funding the vaccine plant in Holly Springs that is paid with BARDA [Biomedical Advanced Research and Development Authority] money. It started when bird flu first started to look like it could jump to people in the late '90s. That scared a lot of folks and governments around the world, led by the U.S., and the World Health Organization [WHO] started to put pieces in place.
Over the last 20 years, a lot of groundwork has been done in terms of developing bird flu vaccines for birds and eventually for people. That includes a lot of the initial testing to figure out what kinds of vaccines might be effective both in birds and maybe even in people. Right now there's not a market for 300 million bird flu vaccines for humans, but if the day comes when there is, we should be able to crank them out pretty quickly. I just hope that if we need a vaccine, there is more public trust than we saw when the COVID vaccines were rolled out. Hopefully, we don't have to find out. Being prepared is a good strategy because the ecology of avian flu has changed here in the U.S. versus how it used to be.
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What else should people know about avian flu?
The State of North Carolina is one of the best prepared because we're one of the most practiced at responding to these types of threats and challenges. A lot of this bird flu preparedness, at least on the poultry side, came out of our hurricane disaster response teams. When hurricanes hit, a lot of farms down east get flooded. In terms of building infrastructure to get farmers back up and running in response to natural disasters, Hurricane Floyd [in 1999], is probably the pinnacle example. We developed ways to protect citizens, protect property and get farmers back up and running. Our state emergency team brought veterinarians in, and so there are veterinarians in the North Carolina Department of Agriculture whose job is disaster response, and they're part of the team that would otherwise show up and help a farmer, help the U.S. Department of Agriculture depopulate a farm, clean up the farm, test it and make sure that it's free of virus.
It's bad enough that farmers lose all of their birds and their livelihood during an outbreak, but then there's several months of downtime after that. The state has figured out ways, working with the U.S. Department of Agriculture as a partner, to get as many farmers and workers employed and generating income as soon as possible so they're not sidelined for six months while they've got bills to pay. We know that effects ripple through the economy, but it's difficult to calculate all the ways. We know how much we spent to get the farmer back to work, but how much money was lost at the local feed and seed store, or at the Waffle House down the street when folks were out of work? How much did it cost the taxpayers because egg prices had gone up twofold, threefold, fivefold? This sort of new reality of endemic avian flu, not just outbreaks anymore, has ramifications - second-, third- and fourth-order effects that take a while to realize.
What about using vaccines?
We could use vaccines, and there are reports that some vaccine companies have already gotten approval to start manufacturing the vaccine for use in birds, but that doesn't mean companies will use them. Vaccinating your birds causes international trade issues. There's a lot of nuance but the short version goes something like this:
All countries that are part of the World Trade Organization [WTO] and want to sell their poultry products on the international market are required to demonstrate that a list of diseases aren't in their flocks. If you can demonstrate that your birds are completely free of bird flu, other WTO trading partners are expected to accept your products. The WTO doesn't forbid the use of vaccines, but if you do vaccinate, other countries don't have to take your product. We've always tried to produce poultry without vaccinating to eliminate doubt and avoid raising trade concerns.
Historically, the U.S. has only had to deal with bird flu outbreaks sporadically, and our strategy of not using vaccines, and quickly containing outbreaks worked. While clean-up costs for outbreaks were expensive, over the long term it was cost-effective on the macro scale.
Now that begs the question, can we maintain the old way of containing outbreaks in bird flu? Is that approach still going to be cost-effective overall? We don't know, but we need to do the math. If we haven't crossed that line yet, we're probably getting really close. But the industry knows once we cross that line, we may not ever be able to go back. We'll likely be able to handle the new virology challenges that come with that decision, but we don't know exactly what that will mean for the economics of poultry production. Poultry is big money, especially for North Carolina. No one wants to make this decision until we know it's the only option we have.
This post was originally published in College of Agriculture and Life Sciences News.
