A highly contagious strain of avian flu that has likely killed hundreds of birds and spread across more than two dozen states has been detected in a human for the first time in the U.S., officials said Thursday.
The man was working on a commercial farm in Colorado and was involved in culling poultry suspected to be infected when he was directly exposed to the H5N1 flu, the state’s health department said in a release.
The man, described as younger than 40, has reported only one symptom — fatigue — and was taking the antiviral drug Tamiflu, the department said.
A positive test administered this week by the state health department, which said it has been monitoring people exposed to poultry and wild birds, was confirmed Wednesday by the Centers for Disease Control and Prevention, the agency said.
Health officials still don't know with certainty whether the man was actually infected with the virus or if the virus had only contaminated the surface of his nose at the time the test was taken, Colorado state epidemiologist Rachel Herlihy told NBC News on Friday.
"With all that said, we are certainly being cautious here and treating this like it could be an infection," she said.
The state health department described the man as a prison inmate who was working at a Montrose County farm as part of a pre-release employment program.
The farm had recently experienced an outbreak of the H5N1 bird flu, and he and other incarcerated individuals had been tasked with helping to euthanize the flock, Herlihy said.
They were given personal protective equipment, though it's unclear whether all of it was being properly used, she said.
The other incarcerated people are being monitored but have tested negative for the virus. The man, who tested positive, has since tested negative but has been asked to remain in isolation until Saturday, she said.
The state health agency and the CDC said Thursday that the risk the virus poses to people still remains low.