Genetic analysis reveals H5N1 flu virus outbreak in cows likely started earlier than thought
The H5N1 bird flu outbreak in dairy cows in the United States has likely been going on for months longer than was previously realized, and has probably spread more widely across the country than the confirmed outbreaks would imply, according to an analysis of genetic sequences that were released Sunday by the U.S. Department of Agriculture.
The genetic data point to a single spillover event that probably occurred in late 2023, Michael Worobey, an evolutionary virologist at the University of Arizona, told STAT on Tuesday.
