Washington state has confirmed its first cases of highly pathogenic avian influenza (HPAI) in dairy cattle, marking a new development in the state’s livestock health monitoring efforts. Federal veterinary authorities confirmed the presence of HPAI H5 in two commercial dairy herds following laboratory testing.
The confirmation highlights the importance of disease surveillance, farm biosecurity and coordination between dairy producers, veterinarians and animal health authorities to limit the spread of infection and protect herd productivity.
Laboratory Testing Confirms HPAI in Two Herds
The US Department of Agriculture’s Animal and Plant Health Inspection Service (USDA APHIS), through its National Veterinary Services Laboratories, confirmed the cases using polymerase chain reaction (PCR) testing. The virus was identified as HPAI H5 clade 2.3.
State animal health officials and local veterinarians are working with the affected dairy producers to monitor cattle health and implement measures intended to prevent further transmission.
HPAI is primarily associated with birds, but certain strains can also infect dairy cattle. Infection in dairy herds can disrupt farm operations, affect milk production and require additional veterinary monitoring and biosecurity measures.
The confirmation makes early detection and appropriate reporting especially important for dairy farms across Washington and neighbouring areas.
Commercial Milk Safety Remains a Priority
The detection of HPAI in dairy cattle has raised questions about milk safety. According to the information provided by agricultural authorities, the commercial milk supply remains safe for consumers when established food-safety requirements are followed.
In the United States, milk sold through interstate commerce is required to be pasteurised. Proper pasteurisation inactivates influenza viruses, including the virus responsible for HPAI.
Milk from sick cows and cows that test positive for the virus is excluded from the human food supply. Milk from affected animals is diverted and must not enter commercial food channels.
Consumers should continue to follow established food-safety guidance, including choosing pasteurised milk and dairy products. Raw milk carries a greater risk of exposure to harmful pathogens and should not be considered a safe alternative.
Maintaining these safeguards is essential for protecting public health and preserving confidence in the dairy supply chain during animal disease incidents.
Dairy Farms Strengthen Biosecurity Measures
Following the confirmation, animal health officials are working with farmers and veterinarians to monitor cattle and reduce opportunities for transmission.
Recommended biosecurity measures include restricting unnecessary visitors and vehicle movements, monitoring animals for changes in health or productivity, and promptly separating sick cattle from healthy animals.
Farmers should pay attention to potential warning signs such as reduced milk production, loss of appetite and lethargy. Any suspected cases should be reported promptly to the appropriate animal health authorities so that testing and further investigation can be arranged.
Careful management of equipment, personnel movement and contact with potentially infected animals can also help limit the spread of disease between groups of cattle and farms.
Surveillance and Veterinary Coordination Remain Essential
USDA APHIS continues to provide disease surveillance, testing guidance and technical support to livestock producers. Cooperation between federal and state authorities, veterinary professionals and dairy operators remains critical for identifying infections and responding effectively.
For dairy businesses, an HPAI detection can create additional costs related to testing, animal monitoring, biosecurity and changes in routine farm management. Maintaining accurate health records and clear reporting procedures can help producers respond more efficiently when disease is suspected.
The first confirmed cases in Washington underline the need for continued vigilance across the dairy sector. Strong biosecurity, prompt veterinary assessment, reliable laboratory testing and strict milk-handling safeguards are central to protecting animal health while maintaining the safety and integrity of the commercial dairy supply.
