Flower Mound Leader > News

Local cities play waiting game following aerial spraying

By Chris Roark, croark@starlocalnews.com

Published: Tuesday, September 4, 2012 2:53 PM CDT
The anxiety or optimism of aerial mosquito spraying in Denton County, depending on which side of the fence you’re on, is now over.

Now, municipalities that participated in aerial spraying must wait to see how effective it was.

Southlake and a host of other cities were sprayed Saturday and Sunday in an effort to rid the area of the many mosquitoes carrying West Nile virus.

The event was originally scheduled for Friday and Saturday, but windy conditions forced spraying to be pushed back a day. Parts of Flower Mound and Lewisville, however, were sprayed Friday night before planes finished the job Saturday and Sunday.

“We were successful in that we got two applications on each city that opted in,” said Bob Martinez, public health preparedness coordinator for the county. “But it will be about a week before we know how effective it was.”

Martinez said the contractor put mosquito traps in various locations before and after aerial spraying to determine how well it worked.

Beginning at 9 p.m., planes covered Denton County – Southlake was included since part of the city is in county limits – to spray a product called Duet, a dual-action adulticide composed of Prallethrin and Sumithrin. Both ingredients are pyrethroids, or synthetic chemical insecticides. It is said to break down in sun and with water and does not stay active after five hours.

Planes used 0.8 ounces per acre of Duet.

Residents were split on their opinions of using the chemical in aerial spraying when they filled the council chambers during a public hearing late last month.

While Denton County’s success rate is not yet known, Dallas County’s effectiveness is encouraging. County officials say that aerial spraying in Dallas County reduced the Culex species of mosquitoes – the species that carries the virus -- by 93 percent.


“Hopefully we’ll see similar statistics,” said Matt Woods, director of environmental services for Flower Mound.

Martinez said there are currently no discussions about another round of aerial spraying in Denton County.

“We’re eager to see those results,” Martinez said.

Martinez said there is a two- to three-week delay in human cases, however, since the incubation period has to be factored in. In other words, there may be a large number of human cases reported in the coming weeks if residents were infected before aerial spraying.

Mosquitoes become infected with the virus after they have bitten a bird carrying the disease. It is then carried to humans when the infected mosquito bites a person.

There are two forms of the disease. People who become infected with the mild case have symptoms such as a fever, headache, nausea and vomiting. People with the neuroinvaise disease can lead to serious, lifelong symptoms, and it can be fatal. Symptoms include a severe headache, high fever, stiff neck, confusion, loss of consciousness or muscle weakness.

County-wide, there have been 145 human cases, which is the highest rate in the state, and two deaths. Of those 145, there have been 43 cases in which a human contracted the neuroinvasive disease.



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