On Jul. 3, 2024, the Centers for Disease Control and Prevention (CDC) reported that a human case of highly pathogenic avian influenza (HPAI) A(H5) virus infection in the United States was identified in the state of Colorado. This was the fourth case associated with an ongoing multistate outbreak of A(H5N1) in dairy cows and the first in Colorado.

As with previous cases, the person was a worker on a dairy farm where cows tested positive for A(H5N1) virus. The person reported eye symptoms only, received oseltamivir treatment, and had recovered.