Washington dairy herds test positive for avian influenza
Two dairy herds in Washington have been confirmed with highly pathogenic avian influenza, the state's first livestock cases since the outbreak began. Federal labs identified the H5 strain, and officials are investigating how the virus reached the farms. The detections have renewed emphasis on biosecurity measures for dairy producers.
Washington's two affected herds had earlier tested negative under a national milk surveillance program, and federal labs used PCR testing to identify the H5 strain, with sequencing still pending. The state joins 18 others that have recorded the virus in dairy cattle since March 2024, though detections have declined this year.
Officials are tracing how the virus entered the farms through testing and on-farm epidemiological work. USDA's eradication approach remains unchanged, relying on surveillance, early detection and limiting transmission between operations.
Dairy producers in Washington and beyond may face added pressure to tighten visitor limits, equipment cleaning and wildlife controls, which could raise operating costs and labor demands. Consumers are unlikely to see milk supply disruptions, since pasteurization is considered effective against the virus. State and federal animal health staff could see heavier testing and investigation workloads, while neighboring farms may weigh movement restrictions as a precaution.