Highly Pathogenic Avian Influenza (HPAI) H5N1, also known as the “bird flu,” continues to spread across the U.S., with concerns recently elevated over a confirmed case in a human who was exposed to infected dairy cattle. To address the spread of HPAI H5N1, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA’s APHIS) has issued a federal order that requires testing of dairy cows for the virus, as well as mandatory reporting.

Effective April 29, 2024, the federal order requires mandatory testing of dairy cattle at an approved National Animal Health Laboratory Network (NAHLN) laboratory prior to the interstate movement of the cows. Owners of herds in which dairy cattle test positive for interstate movement will be required to provide epidemiological information, including animal movement tracing. Dairy cattle moving interstate must adhere to conditions specified by APHIS.

Additionally, to be described in forthcoming guidance, testing will be required immediately for lactating dairy cattle. Testing requirements for other classes of dairy cattle will be based on scientific factors concerning the virus and its evolving risk profile.

The federal order also requires laboratories and state veterinarians to report positive Influenza A nucleic acid detection diagnostic results (e.g., PCR or genetic sequencing) in livestock to USDA APHIS, as well as positive Influenza A serology diagnostic results.

USDA and the U.S. Food and Drug Administration (FDA) stress that the U.S. commercial milk supply is safe because of both the pasteurization process and the required destruction or diversion of milk from ill cows.