Mosquito's carrying West Nile have been trapped in Weld County.
County officials say the mosquitoes were found this week in two of the three testing zones in the county.
Dr. Mark Wallace, executive director of the Weld County Health Department, says the overall risk posed by the virus remains low, but he notes that in recent years it usually hasn't shown up until July.
Initial human symptoms of the virus can include fever, headache, nausea, vomiting, muscle aches, weakness and rash.
More severe symptoms can include stupor, disorientation, coma, tremors, vision loss, paralysis and even death.