Routine national milk testing detected Indiana’s first reported H5N1 case in dairy cattle, USDA announced Nov. 2, 2026. The finding prompted a joint state-federal investigation and renewed USDA’s call for enhanced dairy biosecurity, while the agency said commercial pasteurized milk remains safe.
USDA’s Animal and Plant Health Inspection Service said its National Veterinary Services Laboratories confirmed genotype B3.13 through polymerase chain reaction, or PCR, testing. The detection came through the National Milk Testing Strategy, not surveillance conducted before cattle movement.
Investigation and herd surveillance
APHIS and the Indiana State Board of Animal Health are conducting additional farm investigations, diagnostic testing and collection of information about disease spread. USDA said dairy cattle in 21 states had been infected since the outbreak began in March 2024.
In its program background, APHIS describes national milk testing as a way to track H5N1 across milk supplies and dairy herds. The agency says surveillance helps guide biosecurity measures and efforts to reduce farmworker exposure. That broader monitoring role is distinct from testing tied to interstate cattle movement.
The Indiana detection does not change USDA’s H5N1 eradication strategy, APHIS said. The agency recommends enhanced biosecurity on all dairy farms and asks producers to immediately report livestock showing clinical signs, along with unusual sick or dead wildlife, to their state veterinarian.
Milk safety and exposure risk
USDA said the detection does not affect the safety of the commercial milk supply. In the announcement, it cited FDA’s assessment that pasteurization inactivates the virus. Milk from affected animals is diverted from commercial milk tanks or destroyed to keep it out of the human food supply.
The announcement also cited CDC’s assessment that circulating H5N1 viruses pose a low risk to the general public. People with occupational or recreational exposure to infected birds or mammals face a higher infection risk and should follow CDC precautions.
