Mosquitoes in two Weld County zones have tested positive for West Nile Virus, though no human cases have been reported yet. Health officials urge precautions as mosquito activity increases with the summer heat.

Dr. Letosha Gale-Lowe said the county has noticed a rise in the mosquito population following recent rains and warmer months.

Boulder County Public Health and Weld County both confirmed within two days that there have been the first positive tests of West Nile virus in mosquitoes in those counties.