Avian flu strain H5N9 in Californian duck farm

The first case of the highly pathogenic H5N9 avian influenza strain has been identified on a duck farm in Merced County, California, as confirmed by the World Organization for Animal Health (WOAH). Concurrently, the more prevalent H5N1 avian influenza strain was detected on the same farm. Since early December, nearly 119,000 birds have been euthanised to mitigate the spread of the disease. Richard Webby of the WOAH has communicated to the media that the observed virus combination does not appear to increase the risk of a human pandemic and does not pose a greater threat to human health than the current H5N1 strains spreading among cattle, commercial poultry, and wildlife. In North America, there are currently four strains of avian influenza belonging to the H5 family, two of which are variants of the H5N1 strain. The H5N1 B3.13 version has been identified primarily in dairy cattle and those engaged in dairy farming, while the strain known as D1.1 has chiefly affected wild birds and commercial poultry. Another strain, H5N2, has been detected in the province of British Columbia and represents a reassortment of the H5N1 virus with another avian influenza virus. The scientific community is now focused on the H5N9 strain, which emerged only in Merced County, requiring the adoption of appropriate measures to contain the spread of the viral threat.