The number of workers at a Franklin County commercial egg farm who have now tested positive for avian influenza has increased to eight, according to preliminary test results.
The outbreak at the large farm has the first human cases of highly pathogenic avian influenza, or H5N1, known in the state of Washington.
Of the eight preliminary positive cases, two were confirmed positive Thursday night with additional testing by the Centers of Disease Control and Prevention. Confirmation testing of the other six cases in pending.
The Washington state Department of Agriculture says two more cases in birds of the highly pathogenic form of avian influenza have been reported in two more counties since the Pasco area outbreak was confirmed Oct. 15.
A backyard flock was confirmed to be infected in Kitsap County Oct. 18, and preliminary positive results for a backyard flock in Lewis County were reported Wednesday Oct. 23.
The three detections in Washington state this month are believed to have been caused by migrating waterfowl spreading the virus to domestic chickens and, in the case of backyard flocks, other domestic birds. They are the first three reports in 2024 in the state.