ATLANTA (Reuters) – Colorado has reported three presumptive cases of H5 bird flu virus infection in poultry workers, the Centers for Disease Control and Prevention (CDC) said on Friday. The three people experienced mild symptoms, the CDC said in a statement. The infections occurred in workers who were culling infected animals at a poultry facility that was experiencing an outbreak of H5N1 bird flu, it said.

The symptoms included conjunctivitis, or pink eye, and common respiratory infection symptoms, Colorado officials said in a statement, adding that none of the people were hospitalized. State epidemiologists said the infections appear to have occurred through contact with infected poultry. The CDC said it is sending a team to Colorado to support an investigation and that the risk to the general public remains low.

Human infections with H5N1 avian flu are concerning because of the potential to cause severe disease and possibly spark a pandemic if the virus were to change and acquire the ability to spread easily from person to person, the CDC said. 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 US dairy cows. “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,” the CDC said.

Preliminary testing by Colorado officials showed the thr.