Late summer sees a higher population of mosquitoes in Garfield County, creating an increased risk of West Nile Virus. The strongest concentrations of the type of mosquitoes that may carry the virus have been found in the Parachute and Grand Valley area, due to the warmer temperatures and lower altitude than the rest of the county.
West Nile Virus is carried by certain infected birds and transmitted to people by bites from mosquitoes that have fed on these birds.
"In areas where these mosquitoes are found, less than 1 percent may be infected with West Nile Virus," said Dr. Michael Weissmann, an entomologist and surveillance manager for Colorado Mosquito Control. "Late summer is typically when the risk of West Nile increases, due to higher temperatures."
Mosquitoes are trapped and tested by the Colorado Department of Public Health and Environment to determine whether West Nile is present.
"None of the mosquitoes trapped in Garfield County have tested positive for West Nile this season," said Steve Anthony, Garfield County vegetation manager.
As of Aug. 24, mosquito populations were declining overall throughout Garfield County. However, the Lyons Park rest area in Rifle and Cottonwood Park in Parachute still had elevated mosquito populations. Expected cooler weather in the weeks to come could significantly decrease the adult populations as fall starts to arrive.
Monitoring of the counts will continue using traps set by Colorado Mosquito Control around the county. An update of the prior week's mosquito monitoring will be posted on the county website throughout the summer and early fall every Monday.
Go to www.garfield-county.com, click on "mosquito counts." Resources for West Nile Virus are linked from the home page.
Good prevention includes following the recommendations of the "Fight the Bite!" campaign, and recommendations from the Centers for Disease Control and Prevention.
Garfield County and statewide health departments also recommend following the four Ds: Drain standing water; limit outdoor activity at dusk and dawn, when mosquitoes are most active; use DEET insect repellents, following manufacturer recommendations; dress in long sleeves and pants at dusk and dawn.
According to the CDC, most people infected with West Nile Virus (about four out of five) will not experience any symptoms. Approximately 20 percent of people who become infected will develop West Nile fever.
Symptoms typically begin 2 to 15 days after being bitten by an infected mosquito and include fever, headache, tiredness and body aches, occasionally with a skin rash and swollen lymph glands.
The illness can last anywhere from a few days to several weeks. About one in 150 people infected with the virus will develop a more severe form of the disease, including headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis.
Residents can help by reporting standing water or high mosquito activity to Colorado Mosquito Control at email@example.com or toll-free at 1-877-276-4306.