Health officials confirmed on Friday that a person in Missouri has become the first in the United States to test positive for bird flu without known exposure to infected animals. The adult patient, who had underlying health conditions, was hospitalized on August 22, treated with antiviral medications for influenza, and later discharged after recovery, according to statements from the Centers for Disease Control and Prevention (CDC) and the Missouri Department of Health and Senior Services.
Initial flu tests raised suspicion, prompting further analysis at state and federal laboratories, which confirmed the presence of the H5 strain, commonly known as avian or bird flu. The case marks the 14th bird flu infection reported in the U.S. this year but stands out as the first where the patient had no known contact with animals.
“No H5 infection in dairy cattle has been reported in Missouri,” the state’s health department stated, though it acknowledged prior cases in commercial and backyard flocks, as well as wild birds.
Previously, all bird flu cases in the U.S. had been linked to farmworkers, with the first recorded in 2022. Bird flu is typically found in wild birds and poultry but has been increasingly detected in mammals, including cattle, which experienced an outbreak across the country this year.
The CDC continues to assess the public health risk as low but warned that “circumstances may change quickly as more information is learned.”
While rare human infections of H5 have been reported globally over the years, there has been no evidence of sustained human-to-human transmission, which would significantly raise the threat level.
