ATLANTA — The Centers for Disease Control and Prevention (CDC) recently confirmed detections of highly pathogenic avian influenza (HPAI) in five poultry workers in Weld County, Colo.

On July 19, the agency confirmed two human cases due to workers participating in depopulation activities on a farm infected with HPAI. A few days later, on July 25, three additional cases of HPAI in humans were confirmed at a commercial egg layer operation in Weld County, different from the previous two cases. Of those three, one of them included a presumptive positive case that was reported by the state earlier on July 20.

With these recent cases, the total number of human HPAI cases in the United States since April has risen to 13, with 10 of those occurring in Colorado.

Before this year, there has only been one other confirmed human HPAI case in the United States, which occurred in 2022 involving a poultry worker in Colorado.

State and local officials continue to monitor poultry workers on farms with infected poultry. Currently, a CDC multidisciplinary, bilingual field team is deployed in Colorado to support the state’s response to ongoing HPAI outbreaks. Approximately 118 people have been tested for HPAI in Colorado, according to the Colorado Department of Public Health and Environment.

As two instances of spillover of the dairy H5N1 strain into commercial poultry facilities have occurred in Colorado, the Colorado Department of Agriculture issued a mandatory statewide surveillance for commercial cow dairies to help mitigate the spread of HPAI.

CDC maintains its stance that the risk from the H5N1 virus remains low to the general public as no genetic changes to the virus nor person-to-person transmission have been discovered.