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.)

Most of the bird flu cases reported so far in the U.S. have belonged to an influenza subtype known as HPAI H5N1. The newly reported subtype in Merced County is called “HPAI H5N9.” Although H5N9 has been reported before in the U.S., this was the first time it was reported as “highly pathogenic.”

Bird flu (H5N1) primarily affects birds but has spread to mammals, including humans. While human transmission remains rare, scientists fear mutation could make it airborne, potentially triggering a global health crisis.

This op-ed argues that to fight avian flu and other animal-borne illnesses, we need to overhaul our food system.

Currently, there are a total of 67 confirmed human cases in the United States and one death associated with the bird flu.