Mosquitoes Test Postive for West Nile Virus

Mosquitoes Test Positive for West Nile Virus in Fairfax County

June 22, 2004

Dr. Gloria Addo-Ayensu, Director of the Fairfax County Health Department, announced today that a mosquito pool collected in the Mason district of Fairfax County has tested positive for the West Nile virus. This is the first positive mosquito pool identified this year in the state.

“This is a reminder to residents that West Nile virus is active in Fairfax County and now is the time for people to pay close attention to eliminating mosquito breeding areas around their neighborhoods before more mosquitoes become infected. Removing breeding sites protects everyone and reduces risk of infection for the whole community,” Addo-Ayensu said.

West Nile virus is spread to birds, humans, horses and other mammals through the bite of infected mosquitoes. Most people bitten by an infected mosquito do not get sick. People who do get sick usually suffer a mild flu-like illness. People over age 50 are at greatest risk of serious illness, such as encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord).

Since May, the Fairfax County environmental health staff has taken a proactive approach in combating West Nile virus by treating over 60,000 storm drains with a larvicide which inhibits mosquito breeding. More storm drain treatments are scheduled to begin in late June. While these treatments will not eliminate all of the mosquitoes that carry the virus, the mosquito population may be dramatically reduced. According to Dr. Jorge Arias, Fairfax County environmental health entomologist, “We are closely monitoring mosquitoes this year and have tested over 17,000 so far, looking for West Nile and other arboviruses. Positive mosquitoes lead to increased risk of human infection.”

Twenty-seven human cases of West Nile virus and one death were confirmed in Virginia in 2003. In addition, a total of 1042 birds, 234 horses, and 432 mosquito pools tested positive for West Nile virus last year. Fairfax County has an active outreach and education program “Mosquito Magicians” that help to “make mosquitoes disappear” in the county. Staff are aggressively promoting their mosquito control management program and have compiled an array of education materials for English, as well as non-English, speaking residents.

The Fairfax County Health Department and Virginia Department of Health recommend the following tips for residents to reduce exposure to mosquitoes:

• Use insect repellent products with no more than 30 percent DEET.
• Wear long, loose, light colored clothing.
• Turn over or remove containers in your yard where water collects, such as old tires, potted plant trays, buckets and toys.
• Fill in root-ball holes (from downed trees) or any depression that holds water for more than a week.
• Eliminate standing water on tarps or flat roofs.
• Clean out birdbaths and wading pools once a week.
• Clean roof gutters and downspout screens regularly.