In early September 2024, the Centers for Disease Control and Prevention (CDC) confirmed a human case of avian flu in Missouri. It is the 14th confirmed case of avian flu (also known as bird flu) in the United States—and the first avian flu case that is believed to have occurred with no known work exposure to sick or infected animals.
The person in this case was over 18 years old and had other unspecified medical conditions. The person was hospitalized in late August, given an antiviral medication, discharged and recovered.
The original announcement by the CDC indicated there were no spread of this flu to close contacts or other people. However, in a follow-up weekly flu surveillance report, the CDC noted that a household contact of the person with avian flu also developed similar symptoms on the same day however, no testing was performed. That close contact has since recovered. Neither person was exposed to bird flu through animals or raw milk, the CDC said.
In another update, the CDC noted that the person with confirmed bird flu was not severely ill, but had symptoms of chest pain, nausea, vomiting, diarrhea and weakness. Hospitalization in this case was due to the person’s significant underlying medical conditions, according to the CDC. The update from the CDC also said that the close contact lived with the person whose bird flu was confirmed, and fell ill on the same day.
“The simultaneous development of symptoms does not support person-to-person spread but suggests a common exposure,” the CDC said in its update. “There is no epidemiologic evidence to support person-to-person transmission of H5 at this time.”
Additionally, a healthcare worker who was identified as a second close contact to the person with bird flu developed mild symptoms, but tested negative for influenza. No other cases related to this case have been found.
In its original report, the CDC noted that this case of avian flu was detected through the national flu surveillance system—the first time that has occurred. The CDC has since performed genomic sequencing of the virus that was found in this case. Although there was limited available genetic material, an analysis showed that the bird flu virus in this case was closely related to U.S. dairy cow viruses. The viral material also showed it had similar genetic sequences to those found in birds and other animals that are typically near dairy farms, raw milk and poultry.
At this time, the CDC says the risk of avian flu to the general public remains low, but this may change if new events occur.
