By Julie Steenhuysen and Bhanvi Satija
CDC officials said in a Sept. 12 briefing the agency has been unable to determine if the Missouri case was related to the virus infecting U.S. dairy cattle.
Missouri is leading the state's bird flu investigation with remote assistance from the CDC.
The state's health officials said in an email last week Missouri is considering taking blood samples to look for antibodies that would indicate prior exposure to bird flu. The CDC said serologic testing will be offered to the second healthcare worker.
Caitlin Rivers, an epidemiologist at Johns Hopkins Center for Health Security, said the results of the blood tests will be critical.
"We'll need the serology results to assess whether this is evidence of H5 transmission," she said, adding that COVID-19 activity was also high in August and the symptoms were easy to confuse.
Michael Osterholm, an infectious disease expert with the University of Minnesota, also said it could be "any number of respiratory illnesses".
The confirmed Missouri case occurred in a patient who was admitted to the hospital with underlying health conditions and was tested for influenza as a part of their workup. It was unclear whether the patient's underlying conditions caused the symptoms or the flu.
The Missouri case was the 14th person in the United States to be diagnosed with bird flu this year. The other 13 cases were among farm workers and linked to bird flu outbreaks on poultry or dairy farms.
Bird flu has infected more than 200 dairy herds in 14 states since March, according to US Department of Agriculture data.
Analysis and Breakdown:
The article provides an update on the bird flu outbreak in Missouri, with the CDC conducting an investigation. The state is taking proactive measures, such as considering blood samples for antibodies and serologic testing. Experts highlight the importance of these tests to determine the source of transmission. The confirmed case in Missouri raises concerns, as it is the 14th case in the US this year. Bird flu has already affected numerous dairy herds across multiple states, indicating a widespread issue that requires attention.