Arizona Detects H5N1 Avian Influenza in Dairy Cattle, Quarantines Facility

The Arizona Department of Agriculture (AZDA), in collaboration with the United States Department of Agriculture (USDA), has confirmed the first detection of H5N1 avian influenza in milk produced by a dairy herd in Maricopa County. The affected facility is currently under quarantine as a precautionary measure.

Unlike other cases involving the H5N1's B3.13 strain, cattle in this instance have not shown symptoms associated with the D1.1 genotype. Nevertheless, should symptoms arise, isolation measures will be taken to prevent further spread.

This discovery was part of AZDA's National Milk Testing Strategy, initiated in January, which focuses on farm-level bulk tank testing. The detected D1.1 genotype is distinct from a recent Nevada case and does not pose an elevated risk to humans. Since the start of the year, every dairy in Arizona has been tested, with only this single facility returning a positive result.

Authorities assure the public that pasteurized milk and other dairy products remain safe for consumption, as the pasteurization process eliminates potential pathogens including avian influenza.

Protecting the health of dairy workers and the public is AZDA's top priority. The agency is coordinating with the Arizona Department of Health Services and the Maricopa County Department of Public Health to outline safety protocols, monitor health at the impacted site, and minimize transmission risks. Individuals in direct contact with dairy cattle might face higher exposure risks.

Monitoring and containment efforts will continue, and AZDA encourages dairy workers to adhere to safety guidelines and report any signs of illness in cattle promptly. For the latest updates, stakeholders can visit the AZDA website or contact their local health department.