Bird flu detected in Missouri where patient had no contact with animals before falling ill

A case of bird flu has been detected in a Missouri patient, the first human case of bird flu in the state and the first nationwide in a person who reported no exposure to animals before becoming ill.

The patient, who has underlying health conditions, was hospitalized on Aug. 22. Tests conducted at the hospital confirmed he had avian influenza, the Missouri Department of Health and Senior Services said in a statement Friday.

This is the 14th case of bird flu detected in humans in the United States this year and the first case in which a person contracted bird flu without prior exposure to animals, the Centers for Disease Control and Prevention said Friday.

The CDC has not seen any transmission of bird flu from the Missouri patient to close contacts or others, and says that, while rare, some cases of bird flu do not have an identifiable animal origin.

“The results of this investigation will be particularly important given the current lack of obvious animal exposure. It is important to note that, although rare, new cases of influenza A have not been identified as having an animal origin,” the CDC wrote Friday.

The 13 other cases of bird flu in the United States in 2024 include 10 patients in Colorado, two in Michigan and one in Texas. Of those, the CDC says four patients were exposed to livestock and nine to poultry.

As of February 8, 2022, 617,239 birds have been infected with avian influenza in Missouri, with the last detection occurring in February 2024. The outbreak has affected 13 commercial poultry flocks and 16 backyard flocks, according to the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service.

Wild birds in Missouri are also known to have contracted avian influenza, the CDC said. No livestock herds have yet been infected with avian influenza in Missouri, according to APHIS data.