Overview

• A new H5N9 strain of bird flu was detected on a commercial duck farm in Merced County, California, marking the first confirmed case in U.S. poultry.
• The H5N9 strain is a reassortment of the widely known H5N1 and another low-pathogenic bird flu virus, but experts say it is not currently a greater threat to human health than existing strains.
• All 119,000 ducks at the affected farm were euthanized in December 2024, and there have been no reports of the virus spreading to other farms or wild birds so far.
• The Trump administration's pause on public health communications and withdrawal from the World Health Organization has raised concerns about delays in sharing critical disease outbreak information.
• Researchers emphasize the importance of monitoring genetic changes in bird flu viruses, as reassortments like H5N9 highlight the potential for new strains to emerge.