Unprecedented Bird Flu Strain Found in Dairy Cattle

The USDA's Animal and Plant Health Inspection Service has detected a new bird flu strain in dairy cattle in Nevada, previously seen only in wild birds. This marks the first such occurrence in cows. Two counties' herds have been quarantined, and the strain was identified through the National Milk Testing Strategy.

The U.S. Department of Agriculture has identified a bird flu strain in dairy cattle, marking the first occurrence of this strain in cows, according to an email from the agency's Animal and Plant Health Inspection Service seen by Reuters. Previously, the 957 bird flu infections reported among dairy cow herds this year were caused by a different strain, the USDA stated.

This newly identified strain was highlighted through genome sequencing of milk samples from Nevada. It aligns as the dominant genotype found in wild birds during the recent fall and winter, as per the email. Detection was part of the National Milk Testing Strategy, initiated in December to screen milk for bird flu nationwide.

Reuters has yet to verify the email with the USDA, which did not immediately comment. In a statement dated January 31, the Nevada Department of Agriculture noted quarantines in two counties following bird flu findings, though the specific strain was not confirmed beyond wild bird origins. USDA data, from the same date, indicated four dairy herds in Nevada were affected.

(With inputs from agencies.)