First U.S. detection of virulent H5N9 strain, at a California duck farm, draws scrutiny as evidence of genetic reassortment that could trigger human outbreaks. A new strain of avian influenza has been identified for the first time in the United States, raising concerns that the virus is transforming in a way that could eventually cause wider outbreaks among humans. U.S. officials disclosed the discovery of the virulent H5N9 strain at a California duck farm in a report in recent days to the World Organization for Animal Health, which maintains a database of animal disease threats.
Rare bird flu strain found in California raises potential of wider spread
- Published Jan 28, 2025