Garfield County finds large numbers of mosquitoes locally

The state reports collection of mosquitoes in Mesa, Delta, and three front range counties carrying West Nile virus

June 27, 2014

GARFIELD COUNTY, CO – Mosquitoes are appearing in unusually high numbers in Garfield County, and the highest risk for exposure to West Nile virus is typically from late June through early September. Residents are urged to take precautions against West Nile virus. The best defenses for people are to wear insect repellant and cover exposed skin to avoid mosquito bites.

The Colorado Department of Public Health and Environment (CDPHE) reported June 18 that mosquitoes collected in Adams, Boulder, Delta, Mesa and Weld counties are carrying West Nile Virus. Last year, Colorado seven people died out of the 322 cases of West Nile virus disease reported to the state.

The virus has not been detected in mosquitoes in Garfield County in 2014. However, the number of Culex mosquitoes, which carry the virus, is projected to increase. “We expect to see higher numbers of mosquitoes that carry the virus as we enter the warmer parts of summer,” said Garfield County Vegetation Manager Steve Anthony. The Colorado Department of Public Health and Environment (CDPHE) determined that some of the mosquitoes trapped in three locations in Garfield County in July of 2013 which showed the presence of Culex tested positive as being carriers for West Nile Virus.

The risk of this mosquito-borne disease can affect animal health as well. It is a strain of encephalitis disease, and horses are especially susceptible. Jennifer House, state public health veterinarian, was quoted in the June 19 CDPHE press release as saying: “Although we can’t predict how much West Nile virus activity will occur this summer, it is unusual for Colorado to have this many mosquito pools testing positive for the virus this early in the season.”

Garfield County contracts with Colorado Mosquito Control (CMC) to monitor and treat mosquitoes. Treatment is focused on the application of an organic larvicide product. Truck-mounted fogging is used on limited basis to target emerged Culex mosquitoes in specific areas. CMC has been monitoring and treating mosquitoes in the county since April, Anthony said.

The traps are checked weekly, and provide information on adult mosquitoes and help direct control efforts. Colorado Mosquito Control submits weekly updates to the county regarding the traps, which are available from the home page of the county website, and full reports are posted online at

To help prevent West Nile Virus infection;

  • DRAIN standing water around your house weekly. Don’t forget to drain water from tires, cans, flowerpots, clogged rain gutters, rain barrels, toys and puddles.
  • DUSK and DAWN are when mosquitoes that carry the virus are most active. Limit outdoor activities or take precautions to prevent mosquito bites during these times.
  • DEET is an effective ingredient to look for in insect repellents. Always follow label instructions carefully.
  • DRESS in long sleeves and pants in areas where mosquitoes are active.

For more information about West Nile virus, visit