For the first time in the United States, a pig has been confirmed to be infected with bird flu, or H5N1, the US Department of Agriculture announced on Wednesday, Salon reports.
This unprecedented case was identified in Oregon and has raised concerns among public health officials, as pigs are susceptible to both avian and human flu strains. This unique vulnerability could increase the risk of the virus adapting to spread more effectively among humans. Known for their ability to host multiple flu viruses at once, pigs are sometimes referred to as a “mixing vessel” due to their potential to combine genetic material from human and bird flu viruses, possibly giving rise to new and more infectious strains.
In tandem with this development, the Centers for Disease Control and Prevention (CDC) reported a sharp rise in human cases of bird flu, primarily affecting individuals in direct contact with farm animals. Six new cases have been confirmed in Washington and three more in California, bringing the national total to 36 human infections since April 2024. More than half of these cases have been reported in the past two weeks alone, signaling a concerning acceleration in the rate of human infections.
Although the majority of human cases are traced to direct animal exposure, an investigation remains underway in Missouri, where two individuals contracted the virus without any known animal contact. The CDC found that healthcare workers who cared for these patients did not contract the virus, which has reassured officials that H5N1 has not yet evolved to spread directly between humans.
Despite the ongoing spread of H5N1, the CDC maintains that the overall risk to the general public remains low. However, the infection of a pig introduces an additional mammalian reservoir, which experts caution could create more opportunities for viral evolution. Public health experts worry that as bird flu continues to spread across species, its chances of evolving into a more transmissible form will only increase.
Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai, has noted that a single instance of bird flu in a pig might not be cause for alarm. However, if H5N1 begins to spread within pig populations, this could signal a more serious risk.
“If it doesn’t spread from pigs to pigs and it just happened on that one farm, it’s not a big deal… If it starts to spread from pigs to pigs, then it’s much more of a problem. If it ends up in large pig populations in the US similar to cows, I think this would be a disaster,” he said.
The CDC and USDA continue to monitor developments closely, emphasizing that any adaptation of H5N1 that could improve its ability to infect humans or spread between them would be met with heightened public health interventions.
