Four agricultural workers tested presumptively positive for avian influenza after working with infected poultry at a commercial egg farm.

Four agricultural workers in Washington state tested presumptively positive for avian influenza while working at a farm with an outbreak.

Washington’s cases took place at a farm experiencing an avian influenza outbreak in chickens, according to a news release from the state health department. About 800,000 birds were euthanized after test results on Oct. 15 showed that they were infected with avian influenza.