A man in Colorado has tested positive for the H5N1 bird flu virus, becoming the first person in the U.S. to have a confirmed human case of bird flu stemming from the current outbreak that has impacted commercial and backyard birds.


According to the Centers for Disease Control and Prevention (CDC), the man who tested positive for bird flu had direct exposure to poultry, as he was involved in culling poultry presumed to have the virus. The only symptom he reported having was some fatigue for a few days before recovering.


The Colorado Department of Public Health and Environment (CDPHE) said in a statement that the man who tested positive was under 40, worked at a farm in Montrose County and was largely asymptomatic. The agency noted that there are currently no known cases of this H5 virus spreading among people.


The patient is currently in isolation and was treated with the influenza antiviral drug oseltamivir, said the CDC. Other people who also worked at the Colorado culling operation have so far tested negative, though they are being retested out of an abundance of caution.


Rachel Herlihy, state epidemiologist for the CDPHE, said, “We want to reassure Coloradans that the risk to them is low.”