Mosquitoes can transmit illnesses to humans through their bite.

  • West Nile virus (WNV) and other illnesses can be transmitted through mosquitoes.
  • WNV is the leading cause of mosquito-borne disease in the U.S. and is commonly spread to people by the bite of an infected mosquito.
  • Grand River Mosquito Control District (GRMCD) has traps across Mesa County to monitor mosquito populations.
  • Culex is the type of mosquito that can transmit West Nile virus.
  • August and September are the months we typically see the highest mosquito activity.
  • Simple preventive measures can protect you and your family against West Nile virus.
    • Wear long pants and shirts.
    • Use an EPA-approved insect repellent effective against mosquitoes. Look for a product that contains one of the following active ingredients: DEET, Picaridin, IR3535, oil of lemon eucalyptus or 2-undecanone.
    • Repair holes in screen windows or doors to keep mosquitoes outside.
    • Regularly check for and drain standing water in and around your home. This includes pots, planters, birdbaths, and trash containers.
    • Avoid being outside at dusk and dawn as this is when mosquitoes are most active.
  • Last year more than 50,000 mosquitos were collected from 83 traps across Mesa County. Trap counts were 20% higher than the previous 5-year average making 2019 one of the busiest on record.
  • There were three human cases of West Nile virus in Mesa county during the 2019 mosquito season.
  • COVID-19 Impacts: There is an increase in the number of people recreating outside and traveling to more remote outdoor areas due to COVID-19. This could increase the risk of being exposed to mosquitos and other bugs that carry disease if proper precautions aren’t taken.

Mesa County Public Health, with the help of our partners at GRMCD, developed an online tool where you can view local mosquito activity. Check out the Mosquito Monitor on to monitor trap locations nearby.