H5N1 Bird Flu Detected in Oregon Pig

By Leah Douglas and Tom Polansek

CHICAGO (Reuters) – H5N1 bird flu was confirmed in a pig on a backyard farm in Oregon, marking the first detection of the virus in swine in the U.S., according to the U.S. Department of Agriculture (USDA) on Wednesday.

Pigs pose a significant concern for bird flu spread since they can co-infect with both bird and human viruses, leading to potential gene swapping that could create a new, more hazardous virus capable of infecting humans.

The USDA stated that the Oregon case poses no risk to the national pork supply, and the public's risk from bird flu remains low.

Notably, pigs were the source of the H1N1 pandemic in 2009-2010 and have been linked to other outbreaks. Richard Webby, a virologist at St. Jude Children's Research Hospital, commented that finding the virus on a small farm is less concerning than if it were found on a commercial farm. He added, “If this virus starts transmitting in pigs, that absolutely increases the risk.”

The Oregon farm has been quarantined, with other animals like sheep and goats under surveillance. To prevent the virus's spread, pigs and poultry on the farm were culled, though tests are still pending on some pigs.

The USDA confirmed that the swine infection originated from wild birds and not linked to poultry or dairy farms. Wild bird migration has carried the virus to various livestock. The finding led the USDA to expand its bird flu surveillance to include nationwide bulk milk testing.

Pigs on this farm were not intended for commercial food supply, but the discovery pressured lean hog futures prices at the Chicago Mercantile Exchange.

Poultry and swine on the backyard farm shared water sources, housing, and equipment, which have previously facilitated virus transmission in other states. Marie Culhane, a professor at the University of Minnesota, emphasized the need for pig farmers to be vigilant for further infections, stating that pigs are highly susceptible to influenza viruses.

In 2023, 36 people have tested positive for bird flu as the virus has affected nearly 400 dairy herds, with all but one person being farm workers with known contact with infected animals. Since 2022, the outbreak has led to the death of over 100 million poultry birds in the nation’s worst-ever bird flu crisis.