OLYMPIA, Wash. — As officials continue to track the ongoing outbreak of highly pathogenic avian influenza, which began in 2022 and made a species jump to dairy cattle in 2024, Washington state has confirmed its first detection of HPAI H5N1 in dairy cattle.
Two dairy farm herds in Yakima County, Wash., have been confirmed positive by the USDA’s National Veterinary Services Laboratory.
The Washington State Department of Agriculture, and the Washington Animal Disease Diagnostic Laboratory at Washington State University report that for the past two years they have conducted more than 7,000 HPAI surveillance tests, and that until this outbreak the state’s dairy farms have been clear of the disease.
“We appreciate how difficult this is for our dairy families, farmworkers and veterinarians that are working hard to keep animals safe and healthy,” Dr. Amber Itle, Washington state veterinarian said in a statement. “The most important thing you can do is implement enhanced biosecurity and report symptoms immediately if animals show signs of illness.”
In the past two years since the species jumped to dairy cattle, HPAI has impacted dairy in 19 states across the nation.
The USDA Animal and Plant Health Inspection Service reports that it is has seen the disease in just a small number of dairy farms this year and that the department is working closely with Washington officials to collect complete epidemiological sequencing data that will help understand this infection and to prevent any further spread.
“The affected herds were tested after exhibiting clinical signs consistent with avian influenza,” APHIS said in a release. “Prior to this detection, the herds consistently tested negative through routine surveillance conducted under the National Milk Testing Strategy program.”
Washington officials add that the two farms are under strict quarantine and biosecurity measures and that veterinarians are treating the sick cows.
Among the signs that dairy livestock owners need to look for include any changes in milk appearance, any decrease in milk production, a decline in feed intake, any respiratory symptoms and fever, manure changes, and any large drops in rumination and motility (digestion).
Just like for the poultry industry, dairy cattle producers are urged to utilize strict biosecurity measures involving clothing, vehicles and equipment. HPAI can spread through wild birds and animals, as well as contaminated milk. For Washington state producers with any questions or concerns, the WSDA can be reached at 360-902-1878; or by email at ahealth@agr.wa.gov.
APHIS officials also note that commercial milk supplies are safe, and that the pasteurization process is effective in inactivating the HPAI virus, adding that dairies are required to send milk for human consumption only from healthy animals. The Centers for Disease Control and Prevention also continue to state that the risk of HPAI contraction in humans remains low.
APHIS reports that as of Oct. 14, for the previous 30 days, there have been five cases of HPAI in cattle in three states, with 94 reported cases in cattle for the year.
