Avian influenza confirmed in dairy cattle in Washington for the first time

Highly pathogenic avian influenza (HPAI) has been confirmed in dairy cattle in Washington. These are the state’s first confirmed cases of the virus in livestock, according to an October 8 announcement from federal officials.¹

The US Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) said its National Veterinary Services Laboratories identified HPAI H5 clade 2.3.4.4b in 2 herds using polymerase chain reaction (PCR) testing. Genetic sequencing is still in progress, and APHIS said it will share final results when they become available.¹

Clinical signs prompted testing

Both herds were tested after cattle showed signs consistent with avian influenza. Before then, the herds had repeatedly tested negative through routine surveillance under the National Milk Testing Strategy.¹

APHIS is working with the Washington State Department of Agriculture on additional on-farm investigations, diagnostic testing, and epidemiologic data collection to learn more about the detections and help prevent further spread.¹