More cases of H5N1 have been confirmed in both humans and in poultry in Weld County, Colorado.
Human cases
The Colorado Department of Public Health and Environment (CDPHE) reported that six workers involved with the highly pathogenic avian influenza (HPAI) response to an affected layer flock in Weld County have tested positive for the H5N1 virus.
One July 20, one day after the agency reported the number of cases had climbed to six, it reported another presumed positive case, related to a separate Weld County flock.
Previously, the agency and the U.S. Centers for Disease Control and Prevention (CDC) had reported four confirmed human cases of H5N1 and one presumed-positive case.
CDPHE stated that the workers had mild symptoms, including conjunctivitis (pink eye) and common respiratory infection symptoms, but none were hospitalized.
HPAI in Weld County poultry
The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (AHPIS) reported that on July 19, the presence of HPAI was confirmed in a flock of commercial table egg pullets in Weld County.
However, APHIS has not yet reported the size of that pullet flock.
So far in 2024, Weld County has three flocks affected by HPAI. The first two both involved commercial table egg layers, with those flocks involving 1,313,800 and 1,790,800 birds. All three flock infections occurred in July.
The state’s only other commercial poultry flock to be affected by HPAI in 2024 was a commercial broiler breeder flock in Delta County. The presence of the virus was confirmed in that flock of 66,500 chickens on February 8.
Weld County also had six commercial poultry flocks struck by HPAI in 2024, but the county’s only cases in 2023 involved backyard poultry.
View our continuing coverage of the global avian influenza situation.
