The patient was experiencing "flu-like symptoms" and had "health conditions that can make people more vulnerable to illness," Wyoming's health department said. She was likely exposed to the H5N1 virus through direct contact to an infected poultry flock at her home.

Three veterinarians had antibodies to bird flu virus, which suggests recent infection, the report said. None of them knew they were working with dairy cattle with known or suspect

Avian influenza (H5N1) has been spreading in the United States among dairy cows since last year. View on euronews