Targeting Mosquito Genetics to Combat Zika

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Molly Scheel in her lab at Indiana University. (Robert Franklin, South Bend Tribune)
Molly Scheel in her lab at Indiana University. (Robert Franklin, South Bend Tribune)

Targeting Mosquito Genetics to Combat Zika

Molly Scheel

The pace of progress in global health is determined by our ability to seed, nurture and spread innovation. Through Grand Challenges for Development, USAID uncovers promising ideas and applies rigorous, market-oriented approaches to cut the time it takes to transform ideas in a lab to impact on the ground.

By spreading diseases such as Zika, dengue and malaria, mosquitoes kill more than one million people annually and make countless others sick or debilitated.

Vaccines and drug therapies to combat mosquito-borne illnesses are under development, but there is one genetic scientist who is pioneering a different approach: reducing the mosquito population with baker’s yeast.

Molly Duman Scheel, a professor at Indiana University, has been awarded grants to identify an environmentally safe larvicide that kills mosquitoes before they can transmit diseases to humans.

Scheel grew up in South Bend, Ind., where her father, an insect physiologist at Notre Dame, instilled in her a love of science and the natural world. Her high school biology teacher sparked her interest in genetics and developmental biology and invited her to participate in a high school research program. Molly was instantly hooked and developed a passion for research. At Notre Dame, Molly pursued research in insect developmental genetics and then continued her studies at the University of Chicago.

“We are looking at the genes that regulate development of the Aedes aegypti mosquito, which transmits diseases such as dengue and Zika,” she said. “If we can find a way to modify or kill that mosquito during its juvenile stage, before it bites and transmits the virus, we would prevent the spread of the disease.”

New varieties of larvicides are needed because of increasing resistance to current products and the rising concern about unintended negative effects of pesticides.

“RNA interference could potentially be transformative in the mosquito world.”

Scheel and her team have developed a larvicide that kills nearly 100 percent of Aedes aegypti mosquitoes in a laboratory environment. Known as yeast interfering RNA, the larvicide targets early mosquito nervous system development, preventing the insects from taking flight and transmitting disease. Not only is the larvicide safer and more effective than solutions commonly used in the field, but it can be reproduced through the cultivation of yeast, which is widely available and inexpensive to culture.

Molly Scheel and Dave Severson, a professor at the University of Notre Dame’s Department of Biological Sciences, inspect a barrel for Aedes larvae. / Keshava Mysore

Molly Scheel and Dave Severson, a professor at the University of Notre Dame’s Department of Biological Sciences, inspect a barrel for Aedes larvae. (Keshava Mysore)

A grant from USAID’s Combating Zika and Future Threats Grand Challenge in 2016 is enabling Scheel and her team to move the larvicide testing from the lab to the field. She was one of 26 awardees who received USAID investment to accelerate innovative approaches to fight the Zika outbreak and strengthen the world’s ability to prevent, detect and respond to future infectious disease outbreaks.

While the development of interfering RNA technology happening in Scheel’s lab is still at the proof of concept stage, she and her team are optimistic about the future of this technology.

“I believe this innovation could become a major game-changer,” says Scheel. “My hope is that RNA technology will transform the way in which we effectively combat Zika and other mosquito-borne illnesses around the globe, as well as offer an alternative to existing chemical pesticides.”

The Aedes aegypti mosquito can be found on all continents, except Antarctica, with communities near the equator most affected.

“We hope that the trials go well and can be expanded to multiple parts of the world,” says Scheel. “I’m sure we’ll run into things that need troubleshooting, but we have a strong team and a good chance of making this work. RNA interference could potentially be transformative in the mosquito world.”

Molly Duman Scheel is an associate professor of medical and molecular genetics at the Indiana University School of Medicine-South Bend. She earned a bachelor’s degree at the University of Notre Dame and a doctoral degree at the University of Chicago.

About the Author: Avery Waite is a Program Analyst in USAID’s Center for Accelerating Innovation and Impact and helps manage the Fighting Ebola and Combating Zika and Future Threats Grand Challenges.

Editor's Note: This entry originally appeared in USAID's 2030: Ending Extreme Poverty in this Generation publication on Medium.com.