Four agricultural workers in Washington state have tested positive for bird flu, the first human cases of H5N1 virus to be reported in the state. Washington is the sixth state to report a human infection of avian flu.

Four farm workers who helped cull poultry on an commercial egg farm in Washington are presumed to have been infected with bird flu, making that state the sixth in the country to report human H5N1 infections this year.

Four new cases of bird flu were detected in farmworkers in Washington state this week. Human infections have cropping in six states as the virus spreads among farm animals.