West Nile Virus update

Mosquitoes collected in Woodbridge this month by the Prince William Mosquito Control Program have tested positive for the West Nile virus.

West Nile virus is a mosquito-borne disease that is widespread in this region. Residents play a big role in disease prevention by paying special attention to eliminating mosquito breeding areas around homes and to protecting themselves from mosquito bites while outside from now until the first hard frost.

“Since most of the mosquito species that residents need to control breed in standing water within a few hundred feet of their residence, control measures around the home are the most effective way to prevent mosquito breeding and to reduce the risk from bites,” said Dr. Alison Ansher, health director of the Prince William Health District.

Mosquito testing is used to determine periods of greater risk of contracting West Nile virus. The wide occurrence of positive mosquitoes indicates there is an increased risk of contracting the virus across Prince William County.

Mosquitoes will continue to be trapped and tested regularly from sites throughout Prince William County. The county’s Mosquito Control Program has performed intensive treatment in the vicinity of the positive mosquito pools to kill adult and larval mosquitoes, and will continue larval control throughout the county and possibly conduct an adulticide spray based on future positive trap numbers.

West Nile virus spreads to birds, humans, horses and other mammals through the bite of an infected mosquito.

An estimated 80 percent of people infected with the virus show no symptoms. About 20 percent  of infections cause West Nile virus fever, which is characterized by an acute onset of fever, and can be accompanied by, but not limited to, headache, muscle aches, fatigue and joint pain.

Those over age 50 are at greatest risk of serious illness, such as encephalitis, which is inflammation of the brain, or meningitis, which is inflammation of the lining of the brain and spinal cord.

Very few people who contract the virus suffer from these more severe symptoms. There was one confirmed human case of West Nile Virus disease reported in Prince William County last year, none in 2010 and one in Manassas Park in 2009.

The Prince William Health District recommends the following to reduce exposure to mosquitoes:

• Wear long, loose and light-colored clothing.

• Use insect repellent products with no more than 50 percent DEET for adults and less than 10 percent for children. Follow label instructions when using insect repellents.

• Turn over or remove containers in your yard where any water may collect, such as old tires, potted plant trays, buckets and toys.

• Eliminate any standing water in yards or on tarps or flat roofs.

• Chlorinate or clean out birdbaths and wading pools every three to five days.

• Clean roof gutters and downspout screens regularly.

For more information on West Nile virus, visit the Virginia Department of Health website.