HOUSTON – Harris County officials began aerial spraying for the mosquitoes in parts of Tomball and Jersey Village. While the mosquito population goes down during the dry times, the prevalence of the West Nile virus actually goes up.

Mosquitoes down during dry spells, West Nile virus risk up
July 15, 2009 View larger E-mail Clip More Video Mosquitoes find whatever water they can and often live amongst the birds, spreading the virus.

On Wednesday, planes sprayed 95,000 acres of northwest Harris County, including parts of Spring, Tomball and Jersey Village. But they're not killing the annoying mosquito that bites you at dinnertime or when you're walking the dog.

"We're not targeting those mosquitoes and probably won't kill many of them, not at night," said Malcolm Williams, who will be doing the spraying.

Williams has been spraying mosquito pesticides since the mid-1980s. The equipment on his plane costs over a $100,000 and is used to spray the pesticide as a fine aerosol mist.

"It’s a real fine mist. You'll see it coming out as two streams behind the airplane," William said.

The common Asian tiger mosquito is the one that bites us, but that mosquito does not carry the virus. Williams' pilots are spraying to kill the Culex mosquito. It’s more passive, but carries the deadly disease.

According to the Centers for Disease Control, even if you are one of the few who becomes infected with West Nile, they say four out of five people won't show any symptoms.

Most of those who do show symptoms, such as headache and fever, will overcome the virus on their own.

Only one in 150 people, who actually become infected, will develop serious symptoms.