Researchers have identified four compounds that elicited a similar avoidance response in fruit flies and mosquitoes as their response to the insect repellent N,N-Diethyl-m-toluamide, commonly known as DEET. These compounds may one day be developed into preferred alternatives to DEET that could be used in combination with other strategies to control insects and prevent transmission of the diseases they carry. The investigators also delineated how DEET interacts with insects' antennae and repels insects.
Led by Anandasankar Ray, Ph.D., of the University of California, Riverside, the research was partially supported by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Neurological Disorders and Stroke (NINDS), both part of the National Institutes of Health. The findings were published Oct. 2 in the journal Nature.
Since its introduction in the 1940s, DEET has been the primary insect repellent used in the United States and Europe. In Africa and Asia, however, it is used less often due to its high cost and the inconvenience of requiring frequent re-application to be effective, leading researchers to seek alternatives.
In this study, Dr. Ray and colleagues used two methods to find potential alternatives to DEET. First, they identified the nerve cells in insects' antennae that DEET activates, which causes the production of the protein lr40a that repels the insect. Secondly, they used a computer simulation to screen more than 440,000 compounds for those that were structurally similar to DEET, originated in plants or animals and were already approved for human use.
From the approximately 200 top compounds, the researchers selected four to test with Drosophila fruit flies and Aedes mosquitoes. When presented to the insects, all four compounds activated the same antennal cells as DEET, induced the production of lr40a and repelled the insects. According to the study authors, the findings are a significant step forward in the development of DEET alternatives with possible implications for control of insect-borne diseases that affect humans.
Kain P et al. Odour receptors and neurons for detecting DEET and new insect repellents. Nature DOI: 10.1038/nature12594 (2013).
Adriana Costero-Saint Denis, Ph.D., vector biology program officer in NIAID's Parasitology and International Programs Branch, and Robert Riddle, Ph.D., program director in NINDS' Extramural Research Program, are available to discuss the findings.