By Jamie Martin
A recent study has confirmed that the spread of avian influenza (H5N1) in U.S. dairy cattle began with just one wild bird infection. This event, traced back to Texas in 2023, led to undetected cow-to-cow transmission and rapid spread to multiple states.
Scientists studied over 100 virus variants and newly sequenced data to track the outbreak. The virus strain, H5N1 clade 2.3.4.4b, has already shown its ability to infect birds, poultry, mammals, and humans. It was reported in cattle across North Carolina, Michigan, Idaho, Ohio, Kansas, and South Dakota in 2024.
Researchers found that the virus likely mixed with other low-pathogenic bird flu strains in North America, evolving into a stronger form. After infecting cattle, the flu virus continued to infect other species, including raccoons, domestic cats, chickens, and several types of wild birds.
Importantly, the virus now shows mutations linked to mammalian adaptation, which means it may be more likely to spread among animals—and potentially to humans. This raises alarms among scientists and health officials.
Experts urge immediate action to manage the virus. Strong coordination between animal health agencies and public health teams is needed to stop its spread and reduce the chance of a future pandemic.
As noted in the report, “Influenza A virus is a transboundary pathogen,” requiring a united effort to protect animals and people.
Monitoring livestock health and controlling movement are now crucial steps to contain the risk.
Photo Credit: gettyimages-branex
Categories: National