Overview

• A genetic study identified a mid-2023 wild bird-to-cow transmission in Texas as the origin of the H5N1 outbreak in U.S. dairy cattle.
• The virus has since spread to over 1,000 cattle herds across six states, including North Carolina, Idaho, and Michigan, with actual numbers likely higher due to insufficient surveillance.
• H5N1 has infected other species, such as raccoons, cats, and birds, and has undergone mutations during its spread.
• Dozens of human infections, mostly mild, have been reported, with one confirmed death linked to the outbreak.
• While U.S. health authorities assess the public risk as low, experts warn of the pandemic potential and urge improved monitoring and containment strategies.