Colorado Reports New Human Cases of Bird Flu, Raising State’s Total to 10

A test tube labelled "Bird Flu" and eggs in a picture illustration on Jan. 14, 2023. Dado Ruvic/Illustration/Reuters

Three more poultry workers have tested positive for avian flu in a second farm in Colorado’s Weld County, bringing the number of cases in the state so far to 10, state health officials said on July 25.

Nine of the cases were detected at two poultry farms and one was from a dairy farm, the Colorado Department of Public Health and Environment said in a statement.

The three new cases involved people working directly with infected chickens at a commercial egg layer operation in Weld County, according to the Centers for Disease Control and Prevention.

The workers experienced mild illness and have been offered antiviral drugs for treatment. State health officials said there has been no evidence of person-to-person transmission of the virus.

This brings the number of human cases of bird flu in the United States since April to 13. Three other dairy workers have been infected with the virus, including one in Texas and two in Michigan.

The CDC said the risk to the general public from avian flu remains low but advised workers to wear personal protective equipment when interacting with potentially infected animals.

“There are no signs of unexpected increases in flu activity otherwise in Colorado, or in other states affected by H5 bird flu outbreaks in cows and poultry,” the agency said in a statement.

The CDC said human infections with the “novel influenza A virus,” such as the H5N1, or bird flu, are of concern because the virus has the potential to cause severe and widespread disease.

“To date, we have not seen genetic changes in the virus that would make it more likely to transmit between humans, but we are closely monitoring it,” the agency said.

The Colorado Department of Agriculture has ramped up measures to curb the spread of the virus, including requiring all licensed dairy cow facilities to test milk samples weekly for avian influenza.

State veterinarian Dr. Maggie Baldwin said the state has “not been able to curb the spread of disease” after nearly three months of efforts to navigate the avian influenza outbreak in dairy operations.

“We have seen devastating impacts of this disease not only to our dairy industry, but our poultry industry as well,” Dr. Baldwin said in a statement on July 23.

“With the strong support of the dairy and poultry industries, we feel that this is the best next step in order to protect these vital industries in our state.”

Avian influenza has affected 33 confirmed poultry flocks in Colorado from April 2022 to March 2024, leading to the loss of more than 6.3 million domestic birds in the state, the department said.

The CDC sent a team to Colorado last week after bird flu infections were detected among poultry workers. Colorado Gov. Jared Polis declared a disaster emergency on July 15 to assist affected facilities with response efforts.