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Mosquito Season Is Nearly Upon Us As Chicago Heats Up

Eleven counties, including Cook County, have seen mosquito batches or birds with West Nile virus so far.

Mosquitoes in Illinois can carry the West Nile virus. [Calgary Reviews]
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CHICAGO — It’s been a rainy few months in Chicago, and if the hot wet weather keeps up, we could be in for a buggy Fourth of July weekend.

Floodwater mosquitoes, also known as nuisance mosquitoes, aren’t the kind that can transmit West Nile virus, but they can make life miserable. They thrive in rainy conditions — which Chicago has seen plenty of — with wet weather speeding up their hatching.

And around the July 4th holiday, Chicago has historically seen a big bounce in their numbers, said Patrick Irwin, assistant director of the Northwest Mosquito Abatement District.

After the holiday, people should start being a bit more worried about West Nile, which can be carried by the culex mosquito — which thrive under very hot and very dry conditions. It’s when floodwaters recede, in fact, that the more dangerous mosquitoes emerge.

Melaney Arnold, a spokesperson for the Illinois Department of Public Health, said the state is currently seeing more of the floodwater mosquitoes. And West Nile evidence in culex mosquitoes is popping up, too. So far, 11 counties, including Cook County, have seen mosquito batches or birds with West Nile as of Monday.

She said the department typically does not start seeing mosquitoes transmitting the virus to humans until July.

There have been no recorded cases of West Nile in mosquitoes yet in Chicago, only in suburban Cook County — though it does expect the virus to appear at some point, said Dr. Allison Arwady, acting commissioner of the Chicago Department of Public Health

So far, more than 55,000 catch basins in Chicago have been treated with larvicide, according to a Monday surveillance report. The same report cites more than five thousand female culex mosquitoes — a type that could carry West Nile virus —  have been trapped and tested. The report says the risk of human West Nile virus infection in Chicago is low.

Arwady said Chicagoans should do their part this summer to help keep the number of mosquitoes down. One important thing people can do is empty outdoor sources of water because mosquitoes lay eggs in standing water. She also encouraged people to put up screens to keep mosquitoes from entering homes and to wear long sleeves, pants and socks, along with EPA-registered insect repellent.

“We count on individual residents in Chicago to help with their microenvironments,” she said.

As for bug spray, Irwin said to look for three ingredients important to have in your repellent: DEET, picaridin or oil of lemon eucalyptus. Those are among other active ingredients in EPA-registered skin-applied insect repellents.

Mosquitoes also hate flying in wind, Irwin said, so setting up a box fan or a bigger oscillating fan on a medium setting can keep them away from you outside.

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