Four new cases of bird flu have been confirmed among poultry workers in Colorado, bringing the total number of cases in the U.S. to nine since the first human case of the current outbreak was detected in 2022.

"In coordination with the Colorado Department of Agriculture, the State Emergency Operations Center, and the Centers for Disease Control and Prevention, the Colorado Department of Public Health and Environment is now reporting a total of five human cases of avian influenza in workers responding to the avian flu outbreak at a commercial egg layer operation," the news release from Colorado Department of Public Health and Environment stated.

The U.S. Centers for Disease Control and Prevention (CDC) has confirmed four cases, while one additional case is presumptively positive and awaiting confirmation, officials said.

The investigation is ongoing, but officials suspect that the workers contracted the infection while culling infected poultry at a farm in northeast Colorado. They were tested after showing mild symptoms, including pink eye and respiratory infection signs such as fever, chills, coughing, sore throat, and runny nose. None of the workers required hospitalization.

"Based on the information available at this time, CDC's current H5N1 bird flu human health risk assessment for the U.S. general public remains low. On the animal health side, USDA is reporting that 151 dairy cow herds in 12 U.S. states have confirmed cases of avian influenza A(H5N1) virus infections in dairy cows as the number of infected herds continues to grow," the CDC said in an update.

The officials confirmed that properly handled and cooked poultry products, including meat and eggs, are safe to eat. Bacteria and viruses, including avian flu viruses, are destroyed during proper cooking.

However, the CDC cautions to avoid contact with sick or dead animals, including wild birds, poultry, and other domesticated animals, if possible. It is also recommended to steer clear of animal feces, bedding (litter), unpasteurized ("raw") milk, or materials that have been in contact with birds or other animals suspected or confirmed to have the A(H5N1) virus.

"People who have job-related contact with infected or potentially infected birds or other animals should be aware of the risk of exposure to avian influenza viruses and should take proper precautions," the CDC news release read. They should wear protective equipment when exposed to an infected or potentially infected animal.

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