HPAI detection in Washington dairy herds turns biosecurity into a shared supply-chain task

The confirmation of highly pathogenic avian influenza in two Washington State dairy herds again puts biosecurity at the centre of animal-production chains as a cross-species discipline. On 8 October, USDA’s Animal and Plant Health Inspection Service reported PCR detection of H5 virus from clade 2.3.4.4b. Genetic sequencing is still to be completed. According to APHIS, these are the first confirmed livestock detections in Washington. The affected herds were tested after showing clinical signs consistent with avian influenza and had previously tested negative under routine surveillance within the National Milk Testing Strategy. The agency and the Washington Department of Agriculture are conducting further epidemiological investigations, diagnostic testing and data collection. The official announcement does not change the U.S. eradication strategy. APHIS stresses that biosecurity remains the principal measure for reducing introduction and spread between premises. It also states that milk from affected animals is diverted from the commercial tank or destroyed, and that commercially pasteurised milk is considered safe. For the meat sector, this is not a warning about meat safety. Its relevance is operational: health signals in one species can alter routines for visitors, vehicles, equipment, animal movements and information-gathering at neighbouring or integrated sites. Procurement, logistics and quality assurance should treat animal-health status as continuously updated data, rather than a fixed condition. Separation of flows, access records and rapid reporting of unusual signs remain basic controls for business continuity.