H5N1 Bird Flu Detected in U.S. Pig for First Time: USDA Quarantines Oregon Farm

In a concerning development for animal health surveillance, a pig on a small farm in Crook County, Oregon, has tested positive for the H5N1 bird flu virus, marking the first such case in U.S. swine. The discovery, confirmed by the U.S. Department of Agriculture (USDA) on Wednesday, has prompted a swift quarantine of the farm to contain the virus and prevent further spread.

Officials are awaiting test results for two additional pigs from the same Oregon farm, while two others have tested negative. Although the infected pig did not show any symptoms, the farm decided to test these animals as a precautionary measure due to prior cases of H5N1 found in other animals on the premises.

Experts are particularly cautious because pigs can host both avian and human viruses, creating conditions where viruses may potentially mutate and become more transmissible to humans. However, USDA representatives emphasized that there is no risk to the nation’s pork supply, as the farm is noncommercial and does not contribute to the food market.

The USDA has placed other livestock on the farm, including sheep and goats, under surveillance, noting that these animals share common water sources, housing, and equipment with the pigs and poultry. Infections can spread across species under such conditions, and the USDA aims to monitor this close-knit environment carefully.

The infected pig was euthanized to allow investigators to conduct more thorough testing, including whether the virus truly infected the pig or if the presence of H5N1 particles in its nasal passages resulted from environmental contamination. According to Michael Osterholm, Director of the Center for Infectious Disease Research and Policy at the University of Minnesota, a necropsy is essential to confirm the nature of the virus’s presence.

This finding adds to the current spread of H5N1 among dairy cows across the U.S., where nearly 400 herds across 14 states have been affected. Although there have been 36 reported human cases linked to direct animal contact, primarily with dairy cows and poultry, the Centers for Disease Control and Prevention (CDC) noted that no evidence suggests human-to-human transmission of this strain.

The USDA continues to monitor the situation closely to safeguard animal health, address the risks of cross-species infection, and provide updates on any potential human health implications.