BENTON COUNTY, Wash. — The Washington State Department of Agriculture (WSDA) confirmed a detection of highly pathogenic avian influenza H5N1 in a Benton County dairy herd.
They say the virus was identified through routine surveillance conducted by agricultural officials.
The finding was initially detected by the Washington Animal Disease Diagnostic Laboratory and confirmed by the USDA National Veterinary Services Laboratories.
The affected dairy herd has been placed under quarantine, and veterinarians are treating sick cows. State officials confirmed that pasteurized milk products remain safe for consumers and no milk supply shortages are expected.
Amber Itle, Washington State Veterinarian, commented on the detection and ongoing response efforts across the state.
“Seeing the virus move to another county is disappointing, but our dairy farmers are working hard to implement their biosecurity plans, share lessons learned and help each other get through this,” Itle said. “This isn’t new for the country, but it is new for Washington. I’ve been in awe of how hard our veterinarians and dairy farmers work together every day to keep their cows healthy, keep their workers safe, and keep operating despite all the uncertainty this virus brings with it. This detection was through routine surveillance, enabling us to detect the virus before cows got sick. We hope this will help us to implement measures on farm to prevent transmission within or between other dairy or poultry facilities.”
Clinical signs of infection in dairy cattle include decreased milk production, thicker or yellowish-brown milk, reduced feed intake, fever, respiratory symptoms, changes in manure and a steep drop in rumen motility. Most affected cattle recover with supportive care, with full herd recovery typically taking four to six weeks.
The virus can spread between dairy cattle through infected animals, contaminated milk, shared equipment, vehicles, clothing and footwear, as well as wild birds. State officials urge livestock owners to limit animal movement between farms, sanitize footwear, isolate new animals for 30 days, and separate sick cattle from healthy animals.
Health officials emphasized that pasteurization inactivates viruses and bacteria, ensuring grocery store dairy products remain safe. However, infected cows can shed the virus in their milk, making raw unpasteurized milk and dairy products unsafe. Officials also warned pet owners not to feed raw milk or raw food products to pets.
The Centers for Disease Control and Prevention and the Washington State Department of Health currently rate the overall public health risk from avian influenza as low.
Individuals who work directly with or come into contact with potentially infected livestock or birds face higher risk and are advised to wear personal protective equipment, including gloves, masks, eye protection, and fluid-resistant outerwear.
The WSDA said it will issue news releases for any new counties with confirmed HPAI cases in cattle, while subsequent detections in previously announced counties will be posted on its website.
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