The US Department of Agriculture (USDA) confirmed the detection of the H5N1 bird flu virus in pigs raised on a small farm in Oregon, marking the first case of this virus appearing in pigs in the US, Reuters reported.
Although the risk to the pork supply chain is low and the risk to the public remains low, the emergence of H5N1 in pigs remains a warning to the agricultural sector and public health.
This is particularly worrying because pigs can be infected with avian and human influenza viruses at the same time, creating opportunities for the viruses to reassort and potentially form new strains that are more transmissible to humans.
Pigs were the source of the 2009-2010 H1N1 flu pandemic and have been linked to other strains of influenza. If this had happened on a large-scale farm, the level of alarm would have been much higher, said microbiologist Richard Webby of St. Jude Children's Research Hospital and a World Health Organization (WHO) expert on animal influenza.
Still, he stressed the need to closely monitor the spread of the virus, especially when it comes to wild birds. The pigs at the farm are not part of the commercial meat supply chain, according to the USDA, but the discovery still affected pork prices on the Chicago Mercantile Exchange as concerns spread across the industry.
The pigs and poultry on the farm shared water sources, housing, and feeding equipment, which may have increased the risk of cross-species transmission of the virus, a common route of transmission in outbreaks in other states.
Dr. Marie Culhane, a veterinary medicine specialist at the University of Minnesota who studies swine influenza viruses, said the finding should serve as a reminder for pig farms to increase surveillance and prepare for potential infections in other herds. “Pigs are highly susceptible to influenza viruses and farmers need to be extra vigilant,” Culhane noted.
In 2024, the US had 36 positive cases of avian influenza, mostly among farm workers who had direct contact with infected animals. Since 2022, avian influenza in the US has caused serious damage with more than 100 million poultry culled in the worst outbreak in history.
