By Julie Steenhuysen

(Reuters) -The Centers for Disease Control and Prevention (CDC) said on Friday that the state of Colorado has reported three presumptive cases of H5 bird flu virus infection in poultry workers.

“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,” CDC said in a statement.

All three individuals experienced mild symptoms, it said. The infections occurred in workers who were culling infected animals at a poultry facility that was experiencing an outbreak of H5N1 bird flu, the statement added.

The CDC said the risk to the general public remains low. The agency is sending a team to Colorado to support an investigation, it said.

According to the CDC, all three workers were exposed through contact with infected animals.

The cases are part of a far-reaching outbreak of H5N1 bird flu that has been spreading globally in wild birds, infecting poultry and various species of mammals and causing an outbreak in U.S. dairy cows.

Preliminary testing by Colorado officials showed the three were infected with a novel type of influenza and are presumed to have bird flu. Samples have been sent to the CDC for confirmatory testing.

If positive, they will represent the fourth case of bird flu in Colorado and the seventh U.S. cases of the virus this year.

(Reporting by Devika Nair in Bengaluru; Editing by Muralikumar Anantharaman and Miral Fahmy)