The Centers for Disease Control and Prevention (CDC) has confirmed four human cases of avian flu, or bird flu, in Colorado. A fifth possible case is a presumptive positive, pending confirmation by the CDC. The Colorado Department of Public Health and Environment said all five cases are in workers at a commercial egg layer operation. Three of the five cases confirmed by the CDC are from samples that CDPHE's State Public Health Laboratory sent on Friday for confirmatory testing. The forth was a presumptive positive by the state lab on Friday, and has now been confirmed by the CDC. The fifth test was also a presumptive positive and was sent to the CDC on Saturday for confirmation. There are no additional test results pending at this time. The first case was confirmed on July 3 and was the first human case of avian flu in Colorado since 2022, CDPHE said. Gov. Jared Polis verbally declared a disaster emergency on July 5 in response to the initial bird flu outbreak in Weld County. The workers were culling poultry at a farm in northeast Colorado. State epidemiologists suspect the workers contracted avian flu by working directing with infected poultry. They showed mild symptoms that include conjunctivitis (pink eye) and common respiratory infection symptoms, but none were hospitalized. Officials say it is safe to eat properly handled and cooked poultry products amidst the outbreak. The proper handling and cooking of poultry, meat and eggs kills bacteria and viruses, including avian flu viruses. If you work with dairy cows or poultry that may have avian flu and you start to feel sick, seek medical care or call CDPHE at 303-692-2700, or 303-370-9395 after normal business hours. CDPHE can help you get a flu test and medicine if needed. More information about the avian flu response can be found on the state's website. Last week, federal officials announced the U.S. government will pay vaccine maker Moderna $176 million to accelerate development of a pandemic influenza vaccine that could be used to treat bird flu in people.