Agriculture officials culled all poultry and hogs on a small backyard farm in central Oregon following an outbreak of bird flu that included the first confirmed infection of the H5N1 virus in swine in the United States. There was no threat to the U.S. meat supply, said the Agriculture Department on Wednesday.
Meanwhile, public health officials said three additional human cases of bird flu had been confirmed in Washington, raising the U.S. total to 39 cases since late March. All were in dairy or poultry workers except for a Missouri patient with no known exposure to infected animals. Genomic sequencing indicated there had been no change in the virus that would increase infectivity or transmissibility in humans, said the Centers for Disease Control. The risk to the general public is low, it said.
Highly pathogenic avian influenza first appeared in U.S. domestic flocks in February 2022. It has become the largest animal disease event in U.S. history. More than 104 million birds in domestic flocks have died, and 395 dairy herds have been infected.
Tests by USDA scientists identified the H5N1 avian flu virus in one of the five hogs on the farm in Crook County, Oregon, about 200 miles east of Eugene, the state capital, said the USDA. Tests were negative for two of the pigs, and results were pending on the other two. Bird flu was also found in the poultry. None of the animals were intended for commercial sale.
“There is no concern about the safety of the nation’s pork supply as a result of this finding,” said the USDA. Other animals on the farm, including sheep and goats, are being monitored. “The livestock and poultry on this farm shared water sources, housing, and equipment; in other states, this combination has enabled transmission between species.”
“This detection serves as a reminder for producers of all sizes to understand and address influenza risks,” said Minnesota hog farmer Lori Stevermer, president of the National Pork Producers Council. The council said it has worked with the USDA since 2009 in a swine influenza surveillance program.
In coming weeks, the USDA will work with state and private veterinarians to expand the testing of milk samples from bulk storage tanks “to better assess where H5N1 is present,” said the Animal and Plant Health Inspection Service. “USDA plans to first sample milk in bulk at the regional level, with additional testing at the farm level if necessary, until herds in an area are determined to be free of the virus.”
To date, the virus has been identified in 14 states, but only two of them, California and Idaho, have had new outbreaks in the past 30 days. California leads the nation, with 193 infected herds, followed by Colorado, with 64 herds. Idaho is third, with 36 herds. Colorado and California have implemented different forms of bulk tank testing with the goal of identifying infected herds as quickly as possible.
The USDA has a voluntary bulk tank test system in place now, with 64 herds in 15 states enrolled.