By Julie Steenhuysen and Bhanvi Satija
(Reuters) – U.S. officials reported on Friday that a second healthcare worker in Missouri who had contact with a hospitalized patient infected with bird flu developed mild respiratory symptoms but was not tested for the virus.
The number of individuals in Missouri who came into contact with the bird flu patient and subsequently developed symptoms has now increased to three, all of whom have recovered.
The other two symptomatic cases included a healthcare worker who tested negative for influenza and a household contact of the patient who exhibited symptoms concurrently with the patient but was never tested.
The Missouri patient differed from prior U.S. bird flu cases this year by having no known contact with infected animals, which raises concerns about the virus potentially mutating to spread more easily among humans.
During a briefing on September 12, CDC officials indicated that they have not been able to determine if the Missouri case is connected to the virus affecting U.S. dairy cattle.
Missouri is at the forefront of the state’s bird flu investigation, with the CDC providing remote assistance.
State health officials mentioned in an email last week that Missouri is contemplating collecting blood samples to search for antibodies indicative of previous bird flu exposure. The CDC also noted that serological testing will be offered to the second healthcare worker.
Caitlin Rivers, an epidemiologist at Johns Hopkins Center for Health Security, emphasized the importance of the blood test results.
“We’ll need the serology results to assess whether this is evidence of H5 transmission,” Rivers stated, noting that COVID-19 activity was also high in August, making symptoms easy to confuse.
Michael Osterholm, an infectious disease expert with the University of Minnesota, added that it could be “any number of respiratory illnesses.”
The confirmed Missouri case involved a patient admitted to the hospital with underlying health conditions who was tested for influenza as part of their medical workup. Whether the patient’s symptoms were caused by the underlying conditions or the flu remains unclear.
This case marks the 14th bird flu diagnosis in the United States this year. The other 13 cases were among farm workers linked to bird flu outbreaks on poultry or dairy farms.
According to the U.S. Department of Agriculture, bird flu has infected over 200 dairy herds across 14 states since March.
