New Bird Flu Strain Detected in U.S. Dairy Cattle, USDA Reports

The USDA has discovered a new bird flu strain in U.S. dairy cattle, a first for this animal group. Previously, dairy cows were affected by a singular strain, with farm workers mostly contracting the flu. The spread emphasizes the need for rapid containment to prevent further agricultural impact.

The U.S. Department of Agriculture has detected a new bird flu strain in dairy cattle, an occurrence never before reported in cows. The USDA's Animal and Plant Health Inspection Service made the announcement on Wednesday. Until now, bird flu infections among dairy herds were attributed to a single strain, the agency noted.

Since April, almost 70 individuals in the U.S.—primarily farmworkers—have contracted bird flu while the virus swept through poultry and dairy herds. The outbreak has killed millions of egg-laying hens and caused egg prices to soar, according to the Centers for Disease Control and Prevention. The USDA revealed that genome sequencing from Nevada milk unveiled the new strain in dairy cows.

Reuters initially reported the discovery of a second strain on Wednesday. This strain dominated among wild birds last autumn and winter, identified through the USDA's National Milk Testing Strategy, which screened milk nationally starting in December. Nevada's agriculture department quarantined herds in two counties post-findings, yet didn't specify the strain affecting them.

The Nevada agriculture department didn't comment immediately, although the USDA indicated bird flu in four Nevada dairy herds. Gail Hansen, a veterinary expert, stressed rapid USDA efforts to prevent interstate spread, referencing previous issues when infected cattle moved widely post-initial outbreak in Texas.

"We lagged in control efforts earlier, allowing the virus to hitch a ride with cattle still infectious," Hansen highlighted. "Such oversights mustn't repeat in Nevada's case." Consequently, the USDA mandates flu testing for lactating dairy cows before interstate transit.

Hansen further suggested cattle infected with former strains might lack immunity against this novel one, underscoring the urgency of containment.

(With inputs from agencies.)