APRIL 21, 2025

Most Human H5 Bird Flu Cases in CA Had Exposure to Sick Cows

By Ethan Covey

All but one case of people infected with highly pathogenic avian influenza (HPAI) A(H5N1) virus in California have occurred in dairy workers who were exposed to sick cows, according to a new CDC report.

Findings from the report highlight the continued need for investigating influenza-like illness or conjunctivitis in workers who have occupational exposure to animals infected with the HPAI A(H5N1) virus (MMWR Morb Mortal Wkly Rep 2025;74[8]:127-133).