First U.S. H5N1 Bird Flu Case in Pig Detected in Oregon, Raising Concerns Over Human Risk

Oct 30, 2024, 07:16 PM

The United States Department of Agriculture (USDA) announced on Wednesday, October 30, 2024, that H5N1 avian influenza has been detected in a pig in Crook County, Oregon, marking the first instance of the virus being found in swine in the United States. The infection occurred on a backyard farm that houses a mix of poultry and livestock, including five pigs. The pig was asymptomatic, and further examinations are underway to assess the extent of the infection. Officials stated that the virus originated from wild birds, not from the strain circulating in dairy cows. This development raises concerns among experts because pigs can act as "mixing vessels" for influenza viruses, potentially facilitating the emergence of strains that could more easily infect humans. However, the USDA reported that sequencing of the virus has not identified any changes that would suggest increased transmissibility to humans, and the risk to the public remains low. The farm has been quarantined to prevent further spread, and there is no concern about the safety of the nation's pork supply. The detection comes amid an ongoing outbreak of H5N1 in the United States, which has primarily impacted poultry and dairy farms. Since April, the Centers for Disease Control and Prevention (CDC) have reported 42 human cases of H5N1 bird flu in the U.S., with 15 associated with exposure to infected poultry and 20 linked to sick or infected dairy cows. The USDA is planning to enhance national surveillance of H5N1 on dairy farms and is conducting field trials for two vaccine candidates for use in dairy cows. The discovery of H5N1 in a pig underscores the importance of continued surveillance and biosecurity measures to monitor and control the spread of avian influenza, given the potential implications for animal and human health.