West Nile Virus found in county trap

The Ochlerotatus canadensis is one type of the 3,500 species of mosquitoes that are capable of transmitting West Nile Virus to both humans and animals. File photo: By Entomologist Gene White

UWCHLAN – County health officials on Wednesday announced the West Nile Virus was recently discovered for the first time this year in a mosquito trap placed in the township.

In an advisory released by the Chester County Health Department, officials warned the virus was positively identified on June 24. The health department routinely places traps across the county to monitor mosquito populations and test for the virus, which in rare cases can cause serious illness or death.

Health officials said the chances of a human contracting the virus from an infected mosquito is small, and that the chance of developing a serious illness as a result is even less likely. Still, officials recommend residents take precautions to minimize the risk of infection.

The recommendations included remaining indoors around dawn and dusk while the insects are most active, and wearing long sleeves and pants when outside. Officials also recommended the use of insect repellent.

The last confirmed human case of West Nile Virus was in 2012. That case was the first in the county since 2008, according to the health department.

The county conducts routine surveillance of mosquito populations to determine when control activities, like additional traps, are appropriate. If the problem persists the county may decide to conduct spraying operations to reduce the number of mosquitos. The county conducted its first spraying operation of the year about two weeks ago in East Coventry and East Vincent, according to the health department director Jeanne E. Casner.

“It’s a little early in the year, but we’re not concerned. It’s not uncommon to see a positive this early,” Cassner said.

Health officials said the heightened concern over the West Nile Virus would likely remain until autumn’s first frost, usually in mid-October.

While the June 24 discovery was the first in Chester County, on June 5 a positive sample was collected just across the Delaware County border in Chadds Ford. In addition to Chester and Delaware counties, other positive samples in the state have been collected this year in Adams, Dauphin, Beaver, Centre and Northumberland counties.

The federal Centers for Disease Control and Prevention also recently issued a warning for a new mosquito-based virus called Chikungunya from the Carribean that been found as far north as North Carolina. Symptoms for Chikungunya include headache, muscle pain, joint swelling or rash.

Health officials also supplied a list of suggestions that residents can take to reduce mosquito breeding on their property:

• Dispose of open containers that may collect water, such as tin cans, plastic containers, ceramic pots, etc.

• Drill holes in the bottom of outdoor recycling containers so that water will not collect.

• Keep your property clear of old tires.

• Clean roof gutters, particularly if leaves from surrounding trees have a tendency to plug drains.

• Turn over plastic wading pools when not in use.

• Turn over wheelbarrows and don’t let water stagnate in birdbaths.

• Aerate ornamental pools or stock them with fish.

• Clean and chlorinate swimming pools when not in use. A swimming pool left untended by a family on vacation for a month can produce enough mosquitoes to result in neighborhood-wide complaints. Mosquitoes may even breed in the water that collects on pool covers.

• For stagnant pools of water that cannot be removed or drained, homeowners can buy Bti products such as mosquito dunks at lawn/garden, outdoor supply, home improvement and other stores. That naturally occurring bacterial product kills mosquito larvae but is safe for people, pets, aquatic life and plants.

For more information about the West Nile Virus visit www.chesco.org/wnv or call 610-344-6752.

Follow Daily Local News staff writer Michael N. Price on Twitter @MikePriceWrites and on Facebook at www.facebook.com/michaelnprice.