Mosquitoes from two trap locations in Fruita and Grand Junction have tested positive for West Nile virus.

The Grand River Mosquito Control District collected the mosquitoes on August 8 and 9, 2023. The types of mosquitoes that tested positive were identified as Culex species, which can transmit West Nile virus to people.

This is the first confirmed West Nile activity in mosquitoes in Mesa County this year. 

This information comes after the first human case of West Nile virus is confirmed in a Mesa County resident. There is no specific treatment for West Nile virus, so prevention is key.

This is the time of year when activity typically peaks, so it’s critical for residents to take precautions. 

The best way to avoid getting West Nile virus is to avoid being bitten by mosquitoes. Increased outdoor activity can lead to increased exposure to mosquito bites, so take some easy steps to  protect yourself:

  • Use an EPA-approved insect repellent effective against mosquitoes. Look for one that contains DEET, Picaridin, IR3535, 2-undecanone, or oil of lemon eucalyptus,
  • Dress in long sleeves and pants when in areas where mosquitoes are active,
  • Avoid being outdoors at dusk and dawn; this is when mosquitoes are most active,
  • Drain and remove sources of standing water on your property.

The public can view look at specific mosquito traps on the Grand River Mosquito Control District website,

Colorado Situation

So far this season, there are 22 confirmed human cases of West Nile virus in residents of 13 counties, including Mesa and Delta counties. The state recently confirmed the first death associated with West Nile in Weld County.

In 2022, Colorado had 206 reported human cases of West Nile virus, including 20 deaths.