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Exploring Repellents for Malaria-Transmitting Mosquitoes

UC Riverside Receives $100,000 Grand Challenges Explorations Grant for Innovative Global Health Research by Anandasankar Ray

Ray will explore long-range olfactory repellents for malaria-transmitting mosquitoes

(May 7, 2009)

Anandasankar Ray is an assistant professor in the Department of Entomology at UC Riverside.  Photo credit: Ray lab, UC Riverside. (Additional image below.)Enlarge

Anandasankar Ray is an assistant professor in the Department of Entomology at UC Riverside. Photo credit: Ray lab, UC Riverside. (Additional image below.)

RIVERSIDE, Calif. – UC Riverside announced today that it has received a $100,000 Grand Challenges Explorations grant from the Bill & Melinda Gates Foundation. The grant will support an innovative global health research project conducted by Anandasankar Ray, an assistant professor of entomology. Ray’s project is titled “Novel Class of Long-Range Olfactory Repellents for Anopheles.”

Ray’s project is one of 81 grants announced by the Gates Foundation in the second funding round of Grand Challenges Explorations, an initiative to help scientists around the world explore bold and largely unproven ways to improve health in developing countries. The grants were provided to scientists in 17 countries on six continents.

To receive funding, Ray showed in a two-page application how his idea falls outside current scientific paradigms and might lead to significant advances in global health. The initiative is highly competitive, receiving more than 3,000 proposals in this round.

Project details

Mosquito-borne diseases like malaria cause millions of deaths and enormous suffering in many parts of the world. According to the World Health Organization, approximately half of the world’s population is at risk of malaria, with a child dying of the disease every 30 seconds.

To help reduce mosquito-human contact and thus reduce the spread of this life-threatening disease, new and effective insect repellents that are cheap and environmentally safe are needed.

Ray explained that the malaria-transmitting Anopheles mosquito uses carbon dioxide in exhaled air as an important cue to find human hosts.

“My lab plans to identify odors that inhibit the mosquito’s carbon dioxide-sensitive olfactory neurons,” he said. “In the long term we would like to utilize such volatile inhibitory odors to design long-distance repellents that block the ability of mosquitoes to detect humans and thereby protect large areas.”

Ray expects his research to show that inhibitory odors that block the ability of mosquitoes to detect carbon dioxide in the exhaled human breath are able to mask the mosquitoes’ ability to find humans efficiently.

“There has been incredible progress in the field of insect olfaction in the past ten years due to the application of powerful molecular, genetic, neurophysiological and behavioral techniques,” he said. “Fundamental principles and mechanisms have been unraveled to a large extent. Now is the time to apply the full power of the accumulated knowledge and techniques to address difficult questions like host-seeking behavior.”

Ray will be assisted in the research by UCR graduate student Stephanie Turner. He and Turner plan to collaborate with Ring Cardé, the chair of the Department of Entomology and an expert on mosquito flight behavior.

First the researchers plan to identify novel inhibitors of the carbon dioxide detectors in the Anopheles mosquito using neurophysiology. Next, in a controlled lab setting, they will test these inhibitors for how well they can disrupt carbon dioxide-mediated attraction behavior. Finally, the researchers will test whether the inhibitors can mask human beings from being bitten by mosquitoes.

About Anandasankar Ray

Ray received his Ph.D. in molecular, cellular and developmental biology from Yale University in 2005. He joined UCR in 2007. His awards include Yale University’s John Spangler Nicholas Prize and a Polak Young Investigator Award from the Association of Chemoreception Sciences.

About Grand Challenges Explorations

Grand Challenges Explorations is a five-year, $100 million initiative of the Gates Foundation to promote innovation in global health. The program uses an agile, streamlined grant process – applications are limited to two pages, and preliminary data are not required. Proposals are reviewed and selected by a committee of foundation staff and external experts, and grant decisions are made within approximately three months of the close of the funding round.

Applications for the next round of Grand Challenges Explorations are being accepted through May 28, 2009. Grant application instructions, including the list of topic areas in which proposals are currently being accepted, are available at the Grand Challenges Explorations website.
The olfactory organs of the malaria mosquito <i>Anopheles gambiae</i>. Carbon dioxide is detected in the maxilliary palp.  Image credit: S. Turner, Ray lab, UC Riverside. Enlarge

The olfactory organs of the malaria mosquito Anopheles gambiae. Carbon dioxide is detected in the maxilliary palp. Image credit: S. Turner, Ray lab, UC Riverside.

The University of California, Riverside ( is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

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