July 2, 2014

Wet weather means more mosquitoes this summer

With more than 10 inches of rainfall in June, Kansas ecologists expect mosquitoes will be abundant.

With more than 10 inches of rainfall in June, Kansas ecologists expect mosquitoes will be abundant.

“This year we got a lot of rain,” said Christopher Rogers, an ecologist with the Kansas Biological Survey at the University of Kansas. “We’re going to have a lot of mosquitoes.”

Rogers demonstrated mosquito trapping Wednesday morning at the Great Plains Nature Center, capturing more than 200 of the insects for future testing. Similar traps are in nine locations across Sedgwick County, monitoring the species and number of mosquitoes that carry viruses, such as the West Nile virus that causes fever, headache, skin rashes and, in more serious cases, neurological infection.

The numbers Rogers collects determines mosquito control efforts in Segwick County, said Adrienne Byrne-Lutz, interim director of the Sedgwick County Health Department.

“As these traps are monitored weekly,” she said, “we review it, and the city of Wichita comes up with a plan to treat those areas that have a high number of West Nile virus.”

Overnight, the traps collect hungry female mosquitoes, since males don’t feed on blood, Rogers said. The trap emulates a warm human that exhales carbon dioxide by using a heat source and dry ice – frozen carbon dioxide. Once lured in, the females are pushed downward into a sleeve by a fan.

Back in the lab, Rogers will observe the insects on dry ice to keep them fresh. Many mosquitoes are a drab brown, he said, but other species are “quite gorgeous.”

Some are iridescent with shiny patches that look metallic, Rogers said. Others have furry, black legs and eat other mosquitoes but never bite humans.

The good news, Rogers said, is that very few of the species he collects can even carry viruses.

“There’s tons and tons of mosquitoes here,” he said, “but not all of them carry West Nile virus.”

It’s hard to predict whether viruses will be on the rise as the number of mosquitoes increases, Rogers said. So far this year, there have not been any cases of West Nile reported, Byrne-Lutz said. In 2013, there were 92 cases in Kansas – 11 of them in Sedgwick County.

“The surveillance that Rogers does … is extremely important,” Byrne-Lutz said, “because when we get reports of how many mosquitoes are carrying West Nile virus, then it determines what we end up doing in conjunction with the city of Wichita.”

To stay protected, the county health department has kicked off a prevention campaign called “Fight the Bite.” Byrne-Lutz said to follow the three D’s: dress, drain and DEET.

• Dress in clothing that covers your skin, she said, especially at dawn and dusk.
• Drain standing water – where mosquitoes breed and lay eggs – in places such as pots, gutters, tires, wheelbarrows and wagons. Change the water in children’s pools, pet dishes and bird baths several times a week.
• Use insect repellent that contains DEET, which is the ingredient in most repellents.

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