H5N1 affects dairy cattle in Michigan and large poultry farm in Colorado

The Michigan Department of Agriculture and Rural Development announced today that testing of a dairy herd in Gratiot County has confirmed the presence of H5N1 avian influenza, the first outbreak in the state since June 7.

In further developments related to H5N1, the Colorado Department of Agriculture announced today that the virus has infected a large commercial egg-laying farm in Weld County.

Repetition in a hotspot in Michigan

The Gratiot County outbreak brings the number of H5N1 outbreaks in Michigan dairy herds to 26. In a statement, MDARD Director Dr. Tim Boring said the outbreak was first detected through testing at Michigan State University’s Veterinary Diagnostic Laboratory and that samples would be sent to the U.S. Department of Agriculture’s (USDA) National Veterinary Services Laboratory for further confirmation.

Gratiot County is one of the hotspots of virus outbreaks in both dairy herds and poultry farms in Michigan.

The number of H5N1 outbreaks in dairy herds confirmed by the Animal and Plant Health Inspection Service (APHIS) of the United States Department of Agriculture (USDA) is 140 in 12 states, including 25 in Michigan.

Outbreak in Colorado leads to declaration of emergency

Colorado, another state heavily affected by H5N1 in dairy herds, recently reported some outbreaks in backyard poultry but has now reported the second largest outbreak in commercial poultry since the virus emerged in U.S. birds in 2022. The facility is a laying hen farm with more than 1.7 million birds, according to a Colorado media report.

Weld County, where the farm is located, has also been severely affected by H5N1 outbreaks in dairy herds.

On July 5, Colorado Governor Jared Polis declared a state of disaster emergency due to avian influenza, ensuring the state can provide support and resources to agriculture, according to a Notice yesterday.