The identified “control area” for surveillance of highly pathogenic avian flu in Pitkin County has been released, according to a situation report distributed by the Colorado Department of Agriculture.

“Active surveillance has been completed in Pitkin County with no additional infected premises identified,” the April 22 report states.

The virus was confirmed in a backyard poultry flock in Pitkin County on April 8 after 35 of the 36 birds in the flock died. The remaining bird was euthanized and officials placed the farm under quarantine. It was the first Colorado incidence of highly pathogenic avian influenza in domestic poultry.

“The backyard operation continues to be under quarantine for a total of 150 days since detection was confirmed,” according to the report.

Avian flu does not pose a food safety risk and no human cases have been detected in the United States, but the virus can have a significant impact on farms if it infects a flock.

As of April 22, state officials had detected the avian flu in domestic poultry at two other locations: a commercial boiler chicken breeder in Montrose County with 60,000 poultry and a backyard flock in La Plata county with 38 poultry.

The flock of 60,000 in Montrose County was set to be euthanized by the end of the day on April 22 and the flock of 38 in La Plata County was euthanized April 17, according to the report.

The state veterinarian issued a quarantine order for parts of Montrose County and Delta County and surveillance will be conducted to ensure that the virus has not spread further. The premises of the La Plata County flock are under a 150-day quarantine.

To keep poultry safe, the Colorado Department of Agriculture encourages all backyard and commercial flock owners to take precautions and ramp up biosecurity measures like keeping a closed flock and decreasing interactions between domestic and wild birds.