Heavy Rain, Heat Bring Out Billions Of Mosquitoes In US

Sizzling temperatures and devastating storms in parts of the U.S. created a breeding ground for billions of pesky mosquitoes this summer.

"When temperatures are in the 90s and we have standing water, we're going to have … billions of mosquitoes breeding," Michael Raupp, an entomologist and a professor emeritus at the University of Maryland, said on "CBSN AM" on Monday. "There's going to be a lot of biting going on."

The remnants of hurricanes Henri and Ida dumped billions of gallons of water across multiple states. Raupp said standing water was "the perfect spot for mosquitoes to breed."

Besides emptying birdbaths and turning over filled wheelbarrows, Raupp had another suggestion to cut down on potential mosquito hotspots. People with areas around their homes that don't drain well after storms can buy environmentally safe larvicides that dissolve in puddles, Raupp said.

As for personal protection, Raupp said repellents containing DEET are the "gold standard" but there are alternatives that have the active ingredient picaridin, which became available in the U.S. in 2005, according to the National Pesticide Information Center. Raupp said people can also use botanically based insecticides or buy clothes pretreated with permethrin, which he said is a "very good" insect and tick repellent.

While this summer's storms benefitted so-called inland floodwater mosquitoes, or Aedes vexans, in the Southeast and along the East Coast, Raupp said they aren't known for spreading West Nile Virus, which is the leading cause of mosquito-borne disease in the continental U.S., according to the Centers for Disease Control and Prevention.

The number of West Nile cases in the U.S. are low and concentrated in Western states, Raupp said. However, Culex mosquitoes, which do transmit the virus, aren't limited to the Western U.S.

"In my backyard right now, I've got a lot of Culex mosquitoes that are biting me whenever I go out the backyard, so it's not time to put our guard down," Raupp said. "The mosquitoes are here."

First published on September 13, 2021 / 8:15 PM

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