WASHINGTON — The US Department of Agriculture (USDA) reported a second outbreak of highly pathogenic avian influenza (HPAI) in a commercial egg layer operation in Weld County, Colo., on July 16.

This most recent report affected 1.3 million birds, according to data from the USDA’s Animal and Plant Health Inspection Service (APHIS).

The previous outbreak in Weld County occurred July 8, affecting nearly 1.9 million birds.

Meanwhile, Colorado has also reported six cases of HPAI found in humans this month. On July 3, a dairy farm worker tested positive for the H5N1 virus. Less than two weeks later, five other livestock workers contracted the disease. Of those, four tested positive for HPAI, and one was a presumptive positive case.

The most recent outbreak among humans occurred at a commercial egg layer operation, where approximately 160 workers were conducting depopulation activities. The detection of HPAI in these five workers marked the first case of HPAI in a poultry worker since 2022.

According to the Centers for Disease Control and Prevention (CDC), environmental factors likely played a role in the contraction of the disease.

In a press call on July 16, the CDC said it has not changed its stance on the risk level of HPAI to the public nor its recommendations for poultry and dairy workers.