On Oct. 8, 2026, the U.S. Department of Agriculture (USDA) National Veterinary Services Laboratory (NVSL) confirmed the first detection of highly pathogenic avian influenza (HPAI) H5N1 in two Yakima County dairy farms in Washington state by the Washington Animal Disease Diagnostic Laboratory.

For the last two years, the Washington State Department of Agriculture (WSDA) and the Washington Animal Disease Diagnostic Laboratory at Washington State University have conducted over 7,000 surveillance tests for HPAI that have all been free of the disease.

This marks the first known case of HPAI in cattle in Washington state. Dairy cattle in a total of 19 states have been infected since the start of the outbreak in March 2024. Washington State Department of Agriculture conducted on-farm investigations, testing, and gathered additional epidemiological information to better understand this detection and limit further disease spread. The two farms are under quarantine and have employed strict biosecurity measures. Veterinarians are working to treat sick cows.

Pasteurized milk products remain safe for consumers, and milk supply shortages are not expected.

HPAI can spread between dairy cattle through infected animals and contaminated milk, equipment, vehicles, clothing, footwear and other materials or people that move between farms. Wild birds can also carry HPAI, but they are not considered the primary source of spread of the virus between dairy herds.

Pasteurization inactivates viruses and bacteria in milk, including HPAI virus, helping ensure the safety of the dairy supply. Infected cows can shed the virus in their milk, making raw milk and other raw dairy products unsafe for consumption. Avoid raw dairy product consumption, and do not allow your pets to consume raw milk or other dairy products, or raw foods such as raw meat.

The Centers for Disease Control and Prevention (CDC) and the Washington State Department of Health (DOH) currently consider the risk to the public from avian influenza to be low. However, people who work with or have recreational contact with infected birds, cattle or other potentially infected domestic or wild animals are at higher risk and should take precautions, including wearing personal protective equipment (PPE) such as gloves, masks, eye protection and fluid-resistant coveralls or other outerwear.