Bird Flu Jumps to Pigs in U.S. for the First Time—Is It a Sign of a New Threat?

In a concerning first, a pig at a backyard farm in Crook County, Oregon, tested positive for bird flu, as confirmed by the U.S. Department of Agriculture. The virus, previously found only in poultry and wild birds across the country, was detected in one of the farm's five pigs after poultry at the same site tested positive last week. This discovery has raised questions about the potential risks of bird flu adapting to infect humans.

The farm, housing multiple animal species that share water and shelter, was placed under quarantine, and all five pigs were euthanized for further testing. Officials emphasize there’s no threat to the national pork supply since this was not a commercial operation.

According to an interview with NPR, Dr. Jennifer Nuzzo, a pandemic researcher from Brown University, the ability of pigs to carry multiple flu strains makes them potential "mixing vessels" that could enable the virus to adapt to humans. She points to the 2009 H1N1 flu pandemic, which had swine origins, as an example. Monitoring flu in pigs could be essential for staying ahead of potential risks, Nuzzo noted.

Fortunately, the USDA's genetic analysis of the virus in the farm's poultry has not shown any signs of mutations that would increase the risk of human infection. Although previous cases of bird flu in pigs worldwide did not trigger pandemics, the widespread presence of this Type A H5N1 strain among diverse animal species in the U.S. raises the chances of human exposure, making close monitoring essential.

Flu expert Troy Sutton of Penn State explains that while the pig infection is notable, it doesn’t necessarily elevate the immediate threat to humans. The infection does add urgency to monitoring if the virus begins to spread widely among pigs or impacts human health.

So far this year, nearly 40 human cases of bird flu have been reported in the U.S., primarily among those in contact with infected animals, with symptoms remaining mild. For now, the infection remains a noteworthy but limited incident—one that experts say is worth watching.