This colorized electron microscope image released by the National Institute of Allergy and Infectious Diseases on March 26, 2024, shows avian influenza A H5N1 virus particles (yellow), grown in Madin-Darby Canine Kidney (MDCK) epithelial cells (blue).CDC/NIAID via AP
CDC calls for expanded testing for bird flu after blood tests reveal more farmworker infections
Blood tests of 115 workers on farms in Michigan and Colorado showed eight workers had antibodies that indicated previous infection. The finding suggests the virus may be spreading more widely.