According to the Centers for Disease Control and Prevention, bird flu outbreaks have impacted poultry in 51 states, while the virus has been detected in dairy cows across 16 states.

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.

The United States has reported its first outbreak of H5N9 bird flu in poultry on a duck farm in California, the World Organisation for Animal Health (WOAH) said on Monday.