SARASOTA, Fla. (WWSB) - The CDC is reporting another case of bird flu in Michigan, the third human case associated with an ongoing outbreak of the H5N1 influenza virus in U.S. dairy cows.

This follows one case in Texas in April and another in Michigan earlier in May. All three infections are in dairy farm workers who had exposure to infected cows.

While the first two cases reported only conjunctivitis, or “pink eye”, as the primary symptom, this third case also involved upper respiratory tract symptoms.

The CDC says transmission of bird flu from person to person remains unlikely, and that the primary risk for infection is in other farm workers who have contact with dairy cows. Additional infections are expected going forward, as the U.S. Department of Agriculture is reporting 69 infected herds in 9 states across the U.S. since March. So far, none have been reported in Florida. Steps are being taken to try to prevent further spread of the virus in cattle, with scientists currently developing a bird flu vaccine for cows. All cattle are also currently being tested for bird flu when they cross state lines.

The CDC aims to eventually eradicate H5N1 in cattle, which would also prevent human cases in the future.