Bug Off! UA Scientists Study Mosquito Control
Maricopa County residents are lending a hand in a UA study about mosquitoes. Researchers hope to improve mosquito control methods to mitigate the risk of future dengue fever and Zika outbreaks in communities around the world.

By Faith Schwartz, UA Cooperative Extension
Sept. 28, 2017

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Mosquito test subjects in Michael Riehle's lab in the College of Agriculture and Life Sciences
Mosquito test subjects in Michael Riehle's lab in the College of Agriculture and Life Sciences (Photo: Bob Demers/UANews)

University of Arizona scientists are climbing into storm drains, navigating yards and scaling down drainage areas, trapping mosquitoes and scooping up larvae while trying to discover the best way to control mosquitoes and prevent problems in the future.

Maricopa County residents are participating in the UA study about mosquitoes to help researchers learn how to control dengue fever and Zika outbreaks.

"These mosquitoes are a problem, first because they're a nuisance, but also they can be vectors of serious diseases. We need to have a management plan ready to address any kind of disease control and nip it in the bud," said UA assistant professor Kathleen Walker, assistant specialist for UA Cooperative Extension, part of the College of Agriculture and Life Sciences.

The study itself looks to see if current methods of controlling mosquito larvae and adult populations are working, and which methods work best. Currently, Maricopa County Vector Control, an agency partner on the project, uses two methods to control mosquitoes. Larvae are controlled using a safe, natural product in drainage structures, while ultra-low volume fogging targets adult mosquitoes.

Walker, along with CALS entomologists Dawn Gouge and Michael Riehle and Kacey Ernst, associate professor in the Mel and Enid Zuckerman College of Public Health, are co-investigators on the $1.25 million, four-year contract from the Centers for Disease Control and Prevention. 

Three times a week, UA researchers and graduate students place mosquito traps at 60 locations at homes and in neighborhood parks in Chandler and Gilbert. Storm drains, dry wells and drainage areas are sampled for immature mosquitoes.

"All this gives us an excellent idea of what's going on and if control measures are working," Gouge said. "We're also looking at where mosquitoes are developing, which methods control mosquitoes best and how old our mosquito populations are. Knowing how old mosquitoes are gives us an idea of how well they could vector pathogens, the older mosquitoes being better able to pass on disease-causing pathogens."

In May, when Maricopa County residents found flyers asking for participation taped to their front doors, Walker and Gouge said they were overwhelmed by the response.

One Gilbert resident who agreed to participate has a personal reason for supporting a UA research project involving mosquitoes in the area.

"The viruses carried by mosquitoes are clearly a very serious problem and also one of personal interest to our family," said Hal Nelson, an Arizona State University professor emeritus in mechanical and aerospace engineering. "A very close friend contracted the West Nile virus. She almost died, and after one month in the hospital and two weeks in rehabilitation, she is still many weeks from full recovery.

"The Zika virus is also obviously of grave concern for our younger friends and relatives. Any research to better understand various aspects of the viruses carried by mosquitoes is clearly important, and I applaud your efforts."

After the mosquito-trapping team collates trap results for the week, participating residents receive individual reports on their trap catch for the past seven days.  

"We get the best results when traps are undisturbed and sheltered under porch areas," Gouge said. "We are extremely grateful to the fabulous group of residents hosting traps at their home locations. We simply couldn't do the study without them. This is a smashing example of a project in which the community members become an integral part of an operational research project that will lead to improvements in vector control in their own neighborhood."

Results from the study will provide the information that communities need to develop effective means to control Aedes aegypti, the yellow fever mosquito that can spread several diseases.

"We have to control mosquitoes, because while mosquitoes are not transmitting any viruses in Arizona currently, Aedes aegypti are potential carriers of viruses like Zika and dengue, and Aedes aegypti are notoriously difficult to control," Walker said. "The study will help us see if methods are working."


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Dawn Gouge

UA Cooperative Extension