Blood samples from five healthcare workers in Missouri will be tested for exposure to the avian flu virus, said the Centers for Disease Control in a weekly update on bird flu. The workers developed mild respiratory symptoms while involved in treatment of a patient infected with the H5N1 virus but who had no known contact with animals.
Development of the symptoms raised the possibility of the first known person-to-person spread of the H5N1 virus.
Public health officials in Missouri have not identified the patient or where in the state the illness occurred. The patient was treated with antiviral medications and recovered early this month. Nationwide, 14 human infections with the bird flu virus have been confirmed since last March, all but the Missouri case were among livestock workers.
“To date, only one case of influenza A(H5N1) has been detected in Missouri. No contacts of that case have tested positive for influenza A(H5N1),” said the CDC. Influenza A is the designation for avian flu viruses. H5N1 is the virus that causes highly pathogenic avian influenza, also called bird flu.
One healthcare worker in Missouri tested negative for bird flu. “The five remaining exposed healthcare workers had only mild symptoms,” said the weekly update. “Blood specimens for those who became symptomatic have been collected for H5 antibody testing at CDC.”
Previously, the CDC said a member of the household became ill with similar symptoms on the same day as the Missouri patient, but was not tested and had recovered. The CDC said the incident suggested “a common exposure,” rather than person-to-person spread.
Influenza surveillance systems have given “no sign of unusual influenza activity in people, including in Missouri,” said the agency. More than 5,000 people have been monitored because of exposure to infected or potentially infected animals and at least 240 were tested for bird flu after developing flu-like symptoms.
Bird flu was identified in dairy cattle for the first time in late March, a worrisome development because of the potential for the virus to jump to humans.