Mosquitoes in Mesa County tested positive for West Nile Virus.
Local officials say this is the first confirmed activity of the virus in area mosquitoes this year.
However, other counties across Colorado have already reported positive tests to the state health department.
Jennifer House is a state public health veterinarian.
"We've recently had an increase in the number of positive mosquitoes," House says. "So far we have been able to find West Nile Virus positive mosquitoes in Boulder, Denver, Larimer, Mesa, Pueblo, and Weld counties."