Five cases of bird flu have been identified among workers culling poultry at a farm in northeast Colorado, the state department of health said on Sunday. The commercial egg operation was impacted by H5N1 outbreaks that have also affected wild birds and dairy cows in several states.
Three of the five human cases were announced Friday, and all of those have now been confirmed by the US Centers for Disease Control and Prevention. A fourth case was also confirmed, and a fifth is presumed positive based on state testing. The Colorado Department of Public Health and Environment said in a statement on Sunday that no additional test results are pending.
The workers are believed to have caught the virus through direct work with infected birds. They had mild symptoms including conjunctivitis or pink eye and respiratory problems, but none of them were hospitalized, the state said Sunday.
The investigation into the cases is ongoing with support of a team sent by CDC at the state’s request.
The CDC said Friday its risk assessment for the general public remains low. “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,” it said.
Four people in the US had previously tested positive for bird flu in connection with the ongoing outbreak: one in Colorado, one in Texas and two in Michigan. All were workers at dairy operations. Colorado’s agriculture industry has been hit hard by bird flu, with Gov. Jared Polis declaring a disaster emergency July 5 to ensure that the state can offer support and resources for farms in Weld County.
Poultry products are still safe to eat if they have been properly handled and cooked, the Colorado health department said. The CDC advises that everyone avoid close or long exposure to sick or dead animals, animal poop or bedding. Experts also recommend against consuming unpasteurized or raw milk due to the potential for contamination.
Another state finds bird flu in cattle
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Until the Colorado cases were announced, recent human H5N1 cases in the US had been linked to dairy cattle.
On Friday, the Oklahoma Department of Agriculture, Food and Forestry announced that a dairy cattle herd in the state had tested positive for H5N1 bird flu, raising the number of states that reported impacted herds to 13.
The positive sample was collected in April, the state said, and the herd has fully recovered.
It’s not clear why it took the so long for the state or federal government to report the results.
Since the first cattle infections were reported in late March, 157 herds have tested positive for H5N1 across 13 states. Four states have had more than 20 herds impacted — Texas, Colorado, Michigan and Idaho — according to the US Department of Agriculture.
CNN’s Katherine Dillinger contributed to this report.