The newly reported H5N9 strain was found Monday at a duck farm in Merced County, California, according to the World Organization for Animal Health. The Paris-based organization that studies animal diseases said it's the first verified U.S. case of H5N9 in poultry. The organization said the more common strain H5N1 was also found.

A new strain of H5N9 bird flu was detected at a commercial duck operation in California's Merced County. All the ducks were euthanized.

Both H5N9 and H5N1 strains of avian flu were identified through tests by the US Department of Agriculture's National Veterinary Services Laboratory (USDA NVSL), after the outbreak was first detected last November.

Massachusetts officials announced Wednesday that bird flu is now considered to be “widespread” in the state and urged the public to avoid handling birds or other animals that are dead or appear sick.

Officials said risk to humans remains low, but the state's public health veterinarian said pet cats are "very susceptible" to the bird flu and can become "seriously ill."