The number of bird flu cases in Central Massachusetts is relatively low, compared to a swath of the state that runs from Greater Boston to Southeastern Massachusetts. That message was delivered Wednesday during a virtual update from state health officials on the highly pathogenic avian influenza H5N1 virus.

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 bird flu has been confirmed at a duck farm in California, the first time the variant has been discovered in poultry in the United States, an international agency said.