H5N1 traces found in muscle from culled dairy cow, Michigan reports 3 more affected herds

As part of its food safety testing in the wake of H5N1 avian flu circulation in dairy herds, the US Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) announced today that viral particles were detected in tissue samples, including muscle, from 1 of 96 cows that were tested.

Meat from the culled dairy cows did not enter the food supply. At select FSIS-inspected facilities, the agency collected multiple tissues from the culled animals, including muscle samples from the diaphragm. Polymerase chain reaction (PCR) testing, which can detect virus fragments but not live virus, on the sample was done by the USDA's Animal and Plant Health Inspection Service (APHIS).

Postmortem examination of the animal that tested positive revealed signs of illness, and traceback activities are under way, along with notification of the producer to get further information.

USDA said the actions are part of its routine operations and provide further confidence in the US food safety system.

Virus strikes herd in 10th Michigan county

The Michigan Department of Agriculture and Rural Development (MDARD) today announced that H5N1 has been detected in three more dairy herds, including the first from Calhoun County. The other two farms are in Clinton and Ionia counties.

Samples from the cows tested positive for the virus at the Michigan State University Veterinary Diagnostic Laboratory. MDARD said the USDA's National Veterinary Services Laboratory (NVSL) has already confirmed findings from the outbreak in the Ionia County herd and that the NVSL's confirmation tests are still pending on samples from the Calhoun and Clinton county herds.