A leading bird flu expert says this 'nasty' outbreak is here to stay: 'There's something different about this virus'

• A bird flu has been killing domestic and wild birds across the US since early 2022.
• It has infected more than 15 types of mammals too — including humans.

A "nasty" bird flu which has killed more than 58 million chickens and turkeys across the US "won't go away," a top expert has told Insider.

"Looking at the number of birds that are infected, my gut feeling is that this virus will be established," said Richard Webby, a leading infectious disease researcher at St. Jude Children's Research Hospital.

Bird flu outbreaks are nothing new, but this year's outbreak is different. Historically, bird flu outbreaks have been quickly stamped out through both the rapid natural deaths and the killings, also known as cullings, of infected and exposed farm birds. Before this outbreak, the last highly pathogenic bird flu in the US was in 2017 — it only impacted four states and fewer than 300,000 domestic birds died.

H5N1, the highly pathogenic avian influenza that is causing this year's bird flu, has been around for more than 25 years. But what sets this year's outbreak of it apart is the virus's newfound ability to spread far and wide amongst wild bird populations, Webby said. He suspects H5N1's new virologic properties could give the virus the upper hand in the long run, allowing it to become established in wild bird populations across the US. "This is something we're going to have to live with in one form or another from here on out," he said.

This bird flu is already established in Europe — and the US could be next

This bird flu is already endemic in Europe, meaning it has established a permanent home among the bird populations there, and isn't going to go away as seasons change or migratory birds move along. H5N1 circulates not just in European livestock, but also in other resident birds, including sea birds.

If the bird flu also becomes endemic in the US, Webby says it will force a major reckoning for egg, chicken, and turkey producers nationwide. It's possible they'll have to start vaccinating their flocks against H5N1, something farmers have been reluctant to do because of possible international trade implications and fears vaccines wouldn't completely eliminate the virus from flocks, like culling does.

Bird vaccine trials have already started in countries including France and the Netherlands, and researchers in the US are working on new vaccines for birds too.

"The poultry industry's going to have to deal with this moving forward, would be my guess," Webby said. "If you're a chicken, this virus is bad news."

'This is most definitely a virus we don't want in humans'

For people, the threat of infection with H5N1 is still low.

People cannot get bird flu from infected eggs or poultry that have been properly cooked to an internal temperature of 165 degrees Fahrenheit.

However, you can get bird flu from coming in contact with sick birds or other infected animals. That's how one prisoner in Colorado, and another nine year old girl in Ecuador recently got sick. Experts stress that people should take simple precautions, like avoiding touching carcasses of eagles, foxes, ducks, or other wildlife, and instead contact local wildlife authorities.

Webby says because of the sheer scale of wild birds, domestic birds, and mammals that are being infected with this virus, "we're going to continue to see human cases" popping up here and there, as people continue to come in contact with infected animals.

That doesn't mean that human-to-human spread of H5N1 is imminent, though. Even when the virus recently spread between mammals — at a mink farm in Spain, and (in all likelihood) among seal herds in the US, it didn't yet have the kind of genetic signatures that cause virus-watchers like Webby to fear that we're headed straight for another human pandemic.

Several key things about the virus would have to change in order for it to become adapted to humans, and those changes would, in turn, make the virus worse at infecting birds. But increased contact between humans and wildlife is creating more opportunities for those changes to happen. Webby is alarmed at the level of contact people are having with this virus in the current outbreak, saying that it's probably more than we've ever had during any other bird flu event.

H5N1 does have the capacity to cause serious disease in people — the fatality rate, historically, is around 60%, according to the World Health Organization, which is why Webby says "this is most definitely a virus we don't want in humans."

For now, experts are "waiting to see what happens next," Webby said, but "the fact that we're still talking about it now, a year after it was first detected, I think that says a lot in itself."