A person in Missouri has become the first in the US to test positive for bird flu without known contact with infected animals, authorities announced on Friday.

The adult patient, who had underlying health conditions, was hospitalized on August 22, treated with antiviral medications, and has since recovered and been discharged, according to the Centers for Disease Control and Prevention (CDC) and the Missouri Department of Health and Senior Services.

The initial flu test was flagged as suspicious, leading to further testing in state and federal labs, which identified it as H5, also known as avian or bird flu. This case marks the 14th bird flu infection in the US this year and the first with no known animal exposure.

The Missouri Health Department noted that “no H5 infection in dairy cattle has been reported in Missouri,” although there have been reports of H5 in commercial or backyard flocks and wild birds. All previous bird flu cases in the US have involved farmworkers, including the first case in 2022.

Dive deeper

Bird flu is typically found in wild birds and poultry but has recently been detected in mammals, including cattle outbreaks this year.

It can occasionally infect humans through close contact or contaminated environments.

While the CDC assesses the public risk as low, it cautions that “circumstances may change quickly as more information is learned.”

Historically, there have been rare cases where the animal source of H5 could not be identified, but there has been no evidence of sustained human-to-human transmission, which would significantly elevate the risk.

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