OLYMPIA, WASH. — On Oct. 20, the Washington State Department of Health (DOH) announced four commercial egg farm workers tested presumptively positive for avian influenza. These presumptive cases are the first in humans in Washington.

The workers were all employed on the same farm in Franklin County, Wash., where they were exposed to infected poultry. Last week, the farm reported an outbreak of highly pathogenic avian influenza (HPAI), affecting nearly 840,000 birds.

The four workers experienced mild symptoms and received antiviral medication.

The testing of additional individuals on the farm is currently pending. The number of human cases under investigation in Washington may, therefore, change.

The Benton-Franklin Health District (BFHD) conducted health checks of exposed workers and coordinated testing at the Washington State Public Health Lab. The samples have been forwarded to the Centers for Disease Control and Prevention (CDC) for final confirmation and analysis of the virus. 

BFHD and DOH are working with the Washington State Department of Agriculture and the CDC to determine a regional response to the outbreak.

BFHD and DOH have provided personal protective equipment (PPE) to workers on the farm. The agencies are currently monitoring exposed workers for symptoms of the disease and are providing testing, vaccines and treatment for symptomatic workers.

Washington is the sixth state to identify a human infection of H5N1.

“Washington has monitored the spread of H5N1 closely since it was first detected in poultry in the state in 2022, and our state is prepared with the knowledge, relationships, and tools to minimize its impacts on our community,” said Umair Shah, Washington secretary of health.

The CDC reports a total of 27 human cases of H5N1 in the United States, not including the recent presumptive cases. So far, California, Colorado, Michigan, Missouri and Texas have had confirmed cases in humans.

The CDC continues to consider the risk of H5N1 to the general public as low. People with job-related or recreational exposures to infected birds, cattle or other potentially impacted animals are at higher risk and are encouraged to take precautions, such as wearing PPE.