Aug. 28 2018 12:00 AM

The vicious Aedes species bites during the day, targeting legs and ankles.

An Aedes aegypti mosquito
Shutterstock

People in Southern California have been feeling the itch — and it isn’t just their imaginations. The mosquitoes there are much worse this year than in most residents’ memory, according to a story reported on The laist website.

And the reason so many otherwise tanned legs are red from scratching? Blame it on Aedes, a species of skeeter that isn’t normally the one that bites people there, the Culex.

This invasive species was spotted first in El Monte in 2010. Since then it's been spreading throughout the region.

Experts say that this new bug is way more vicious than the native nuisance. Unlike the Culex, Aedes mosquitoes bite during the day, going for the legs and ankles. Because of that, they don’t buzz around people’s heads and ears, so they don’t hear them coming.

"They're sneaky biters," said Yessenia Avilez, an inspector for the Greater L.A. County Vector Control District.

It's Avilez's job to find and destroy the Aedes mosquito. She and a partner, Faiza Haider, go around checking for breeding grounds. "We're looking for standing water," Haider said. "Something as small as a bottle cap can breed mosquitoes."

While Culex prefer to lay their eggs in big sources of water, like swimming pools, Aedes hardly need any water at all. Both species, however, can carry diseases: Culex transmitted West Nile to six people in L.A. County already this year, while Aedes can potentially transmit the Zika virus and dengue fever.

The women inspect doggy dishes, looking for larvae, and check out empty buckets and flowerpots, looking for the thin white calcium line where water used to be. "The invasive mosquito likes to deposit its eggs right above the water mark," says Haider. The eggs can lie dormant for years, waiting for the pot or bucket to be refilled again.

When she and Avilez find a line of eggs in a dry pot, they take it back to their lab and destroy it, or have the resident give it a good scrubbing with soap or bleach.

Jane Stephens Rosenthal scratches her arms as she watches the inspectors work. She's lived in Los Angeles for five years and called Vector Control because the mosquitoes have never been this bad. "I was out here on a call at 9:30 a.m. for half an hour, and my legs were totally bitten," she said. "They're just nasty."

She tells the inspectors, — who did indeed find an Aedes specimen at her residence — that the source of the pests could be an uncovered rain barrel at her next-door neighbor's house.

"This mosquito doesn't travel very far," Avilez said. "It stays very close by to where it just hatched."

Peering through the fence, they can see a giant uncovered rain barrel. "That's a point of entry," Avilez said, "so mosquitoes can just fly in, deposit their eggs and fly out. It's a perfect environment: It's shaded, there's people, there's food."

Ideally, the inspectors would treat the rain barrel with larvicide right away. But its owner wasn’t home, so a note was taped to the door, saying they’ll return in three days if the owner doesn't call back.

It's illegal in California to ignore a source of mosquitoes on one’s property. Refusing to fix the problem can incur a fine of up to $1,000 a day. That’s the sort of bite that can’t be soothed by calamine lotion.

Unfortunately, seek-and-destroy missions like the one the two inspectors just did have some heavy odds against them. For one thing, heat speeds up the Aedes' reproductive cycle. That means the invasive mosquito infestation could get worse in the future, as temperatures rise due to climate change.