Bird flu is now believed to be widespread in Massachusetts and is likely present even in places where there has not been a confirmed positive, state environmental and health officials said Wednesday.

The California duck farm's strain of H5N9 is different from those earlier cases because this time it is closely related to a newer variant of the H5N1 virus. That variant is called H5N1 D1.1, the USDA spokesperson said, which has emerged over the past year to dominate U.S. cases in wild birds and poultry.