A person in Missouri has been infected with bird flu, the Centers for Disease Control and Prevention said Friday. The adult, who didn't have known contact with poultry or dairy cows, was hospitalized on Aug. 22 and has recovered.
The case adds to growing anxiety about the risk of bird flu spreading among humans, especially since this is the first infection in a person in the U.S. who didn't work with poultry or dairy cows.
The CDC said the risk among the general public remains low.
At least 196 herds of dairy cows in 14 states have confirmed outbreaks of the H5 influenza virus, according to the CDC. Outbreaks among poultry have been detected in 48 states. Based on CDC data, the patient in Missouri is the 15th human case of H5 reported in the U.S. since 2022. Since the beginning of 2024, 14 poultry and dairy workers have been infected. Most had mild flu-like symptoms, including fever or runny nose. Many have had conjunctivitis or pink eye.
No H5 infection in dairy cattle has been reported in Missouri. There have been some cases reported in commercial poultry or backyard flocks and wild birds.
"The question now is: How did this patient acquire the infection?" said Dr. William Schaffner, an infectious diseases expert at Vanderbilt University Medical Center in Nashville, Tennessee. "We need a very, very thorough investigation."
There has been no evidence that H5N1 — the H5 virus spreading in dairy cows — has been spreading from person to person. The sample from the Missouri patient will need to be studied in the laboratory to see whether the H5 virus might have acquired mutations that make it easier to transmit in humans, Schaffner said.
"This will be of enormous interest," he said.
In a separate release, Missouri health officials said there has been no sign of unusual influenza activity in people, including no increase in emergency room visits or in laboratory detection of human influenza cases in the state.
The Missouri State Public Health Laboratory was sent a sample from the patient, Missouri health officials said in the release. The sample was sent to the CDC for further testing.
The adult patient has underlying medical conditions and tested positive for influenza A, Missouri officials said. No transmission of the virus has been identified among the patient's close contacts.
