A person in Missouri is the United States’ first case of H5 avian influenza without a known exposure to a sick animal, the US Centers for Disease Control and Prevention said on Friday.
“This is the 14th human case of H5 reported in the United States during 2024 and the first case of H5 without a known occupational exposure to sick or infected animals,” the CDC said in a statement.
It’s also the first H5 case detected through the country’s national flu surveillance system rather than targeted surveillance of the ongoing bird flu outbreak in animals.
The case is under investigation by the Missouri Department of Health and Senior Services.
The person tested positive for influenza A, was treated with influenza antiviral medications and is now recovered and at home, according to MDHSS.
A sample from the patient was sent to the CDC, which confirmed that the case was a type of bird flu.
Flu viruses are classified based on two proteins that sit on the surface of the virus an H, or hemagglutinin, protein, and an N, or neuraminidase, protein.
A spokesperson for the CDC said the agency had confirmed the flu type is H5, but has not yet determined the N type.
Scientists at the CDC hope to have more information on the genetics of the virus in the coming days, the spokesperson said.
There are no cases of bird flu among cattle in Missouri, but there have been outbreaks of the virus among poultry in the state.
According to information released on Friday by the US Centers for Disease Control and Prevention, a person in Missouri is the country’s first H5 avian influenza case without a known connection to a sick animal.
In a statement, the CDC stated that this was the first case of H5 without a known occupational exposure to sick or infected animals and the fourteenth case of H5 in humans to be reported in the US in 2024. Additionally, it’s the first H5 case identified by the nation’s national flu surveillance system, as opposed to focused monitoring of the ongoing animal and bird flu outbreak.
The Missouri Department of Health and Senior Services is looking into the case. August 22nd saw the patient’s hospitalization due to underlying medical conditions. MDHSS reports that the patient tested positive for influenza A, received antiviral medication treatment, and is now well and back at home.
The CDC received a sample from the patient and verified that the illness was a particular strain of bird flu. The H protein, or hemagglutinin, and the N protein, or neuraminidase, which are proteins that reside on the surface of the virus, are used to categorize flu viruses. The CDC confirmed that the flu type is H5, but the N type has not yet been identified, according to a spokeswoman. Their current tasks include separating the virus and deciphering its genetic code. According to the spokeswoman, CDC researchers anticipate learning more about the virus’ genetic makeup in the days to come.
Researcher’s understanding of the patient’s genetic makeup will help determine how similar the virus that afflicted her may have been to the viruses that are currently causing outbreaks in US cows, chickens, and other mammals.
Although there have been outbreaks of the virus among poultry in Missouri, there are no cases of bird flu among cattle.
The CDC stated that its risk assessment for H5N1 in the general population is still low.
Brenda Goodman of CNN contributed to this story.
