H5N9 is “not commonly seen in poultry in general,” says Eman Anis, assistant professor at the University of Pennsylvania School of Veterinary Medicine. (Anis is part of a lab that conducts national testing of poultry samples for avian influenza.)

While the H5N1 bird flu keep spreading, the first reported H5N9 outbreak in the United States has been identified on a duck farm in California.

Nearly 119,000 birds have been culled at a farm in California after a bird flu called H5N9 was detected among the poultry