Public health officials in Colorado on Wednesday announced an adult man had tested positive for avian flu after reporting mild symptoms, including conjunctivitis, or pink eye.
The man is an employee at a dairy farm who had exposure to infected cattle and recovered after antiviral treatment, officials said.
It was the fourth human case of bird flu reported in the US since avian flu was confirmed in cows in March. The prior three people to test positive were also dairy farm workers who recovered.
The first two workers to contract the virus had mild pink eye. In the third case, the worker had mild respiratory symptoms.
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The Centers for Disease Control and Prevention confirmed the case in a statement and said the risk to the general public from bird flu remains low, although people with exposure to infected animals are at greater risk.
The virus has infected cows at 139 farms in 12 US states, according to the US Department of Agriculture. Colorado has had 27 of those outbreaks.
On Tuesday, Moderna (MRNA.O) was awarded a $176 million government contract to advance development of its human bird flu vaccine.
The USDA is conducting its own research as well as soliciting information from about two dozen companies on a potential bird flu vaccine for cattle, although the agency has said it hopes to eliminate the virus from dairy herds without the use of a vaccine.
