Mosquitoes trapped in Garfield County show West Nile presence |

Mosquitoes trapped in Garfield County show West Nile presence

The Colorado Department of Public Health and Environment has determined that some mosquitoes trapped in three locations near Rifle and Battlement Mesa and Parachute have tested positive as carriers for West Nile Virus.

Colorado Mosquito Control, Garfield County’s mosquito control contractor, sent five mosquito pool samples to the department to analyze the collected samples for West Nile Virus. Three of the five July 9-10 samples tested positive, stemming from mosquitoes collected in Willow Creek in Battlement Mesa, Parachute’s Cottonwood Park and Mile Pond Road, just southeast of Rifle.

Traps are located at 11 locations throughout the county. Colorado Mosquito Control checks the traps once a week, which provide information on adult mosquitoes and help guide control efforts. Colorado Mosquito Control provides weekly updates to the county regarding the traps, which are available on the county website, The charts in the update reflect the quantity of mosquitoes trapped in a single night in a specific location, and also break down the trap count by individual species.

The species of mosquito of concern is Culex tarsalis. Culex is indicated in red in the update’s pie charts. Culex numbers that approach 50 or greater in a trap in a single night are a concern. This usually leads to a limited, truck-mounted fogging of the affected area for adult mosquitoes by Colorado Mosquito Control. When Culex counts are in that range, residents should safeguard themselves to minimize their exposure to mosquitoes. Culex is most active at dawn and dusk.

Culex (the carrier of West Nile), was high last week in the following spots in Garfield County:

Location Culex

· Willow Creek in Battlement Mesa 112

· Parachute Cottonwood Park 107

· Rifle Rest Area 95

· Mile Pond Road 66

· Silt Roundabout area 48

· Coal Ridge High School 55

The season’s first human case of West Nile virus was reported on July 3 in Delta County, prompting Garfield County Public Health Department staff to increase awareness and prevention efforts. The department encourages residents to drain standing water, dress in long sleeves and pants at dusk and dawn when mosquitoes are most active, and use an effective insect repellent.

“We live in an area where Culex mosquitoes – the ones that carry the West Nile virus – are present. But that doesn’t mean we need to refrain from doing the outdoor activities we enjoy; it just means we need to take a few simple precautions,” said Yvonne Long, director of Garfield County Public Health. “When it comes to discouraging mosquito bites, DEET is the gold standard by which all other repellents are judged.”

“We know that DEET is effective and safe when used properly,” Long continued. “However, we also know that people are interested in alternatives, and may not know which of these are effective against bites.”

For people looking for alternative active ingredients, including those derived from plants, there are resources available to help make the appropriate selection. The Environmental Protection Agency website “Search for a Repellent that is Right for You,”, lists EPA registered repellents and the amount of time each is effective.

“Be sure to choose a repellent with a protection time that fits your activity, perspiration level, your environment, and how attractive you are to insects. It is also very important to re-apply repellent according to label instructions,” said Long.

For more information on West Nile virus prevention, contact the county health department at 625-5200, go to or For information regarding the county’s mosquito control program, contact Steve Anthony, county vegetation manager, at 945-1377, ext. 4305.

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