West Nile cases down in DuPage County

Updated 9/7/2011 3:15 PM

At least our rainy summer has one benefit: Fewer mosquitoes that carry the West Nile virus.

Those culex mosquitoes love stagnant water. But his summer, it frequently has been replaced by fresh rainwater. And with temperatures fluctuating from exceedingly hot to unseasonably cool, conditions have been unfavorable for the insect.


But that good news has been tempered by a recent surge in the West Nile-carrying mosquitoes after a relatively dry spell accompanied by warm temperatures last week.

"The (culex) prefers the stagnant and hot conditions," Hass said. "Now that we have gotten into where we have had a little less rain and hot weather, more reports of positive mosquitoes are coming in."

The health department monitors about 40 traps across the county two times per week, and last week found four traps in Wheaton alone with infected mosquitoes.

On July 6, the first infected mosquito was found in Lemont. The infected mosquitoes are generally most prominent in July and August. But heavy rains in July slowed the spread of the culex and recent cool temperatures are expected to bite into its numbers.

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"As soon as we get cool weather or at the first frost, it slows them down," Hass said.

After receiving word from the health department of the positive tests for the virus, the Wheaton Mosquito Abatement District sprayed the area to curtail its spread.

Thus far, four people in Illinois this year have tested positive for the West Nile virus, with none of those in DuPage, Hass said.

According to the Illinois Department of Public Health, symptoms of West Nile typically occur between three and 14 days after a bite from an infected mosquitoes. Although mild cases are characterized by a slight fever or a headache, more serious infections can lead to high fever and body ache and, ultimately, death.

But Hass stresses that most people do not have to be overly cautious and should be fine by covering themselves in repellent and dumping standing water near their homes.

"Generally, people who are healthy and strong, it has very little to no impact," he said. "People who have other illnesses, it's more of a problem for them."