Secrets of insect repellent DEET could prove decisive in the war on malaria, dengue and West Nile fever
Researchers use new screening method to find four repellents that are as powerful as substance used effectively for more than 60 years to protect people
Steve Connor is the Science Editor of The Independent. He has won many awards for his journalism, including five-times winner of the prestigious British science writers’ award; the David Perlman Award of the American Geophysical Union; twice commended as specialist journalist of the year in the UK Press Awards; UK health journalist of the year and a special merit award of the European School of Oncology for his investigative journalism. He has a degree in zoology from the University of Oxford and has a special interest in genetics and medical science, human evolution and origins, climate change and the environment.
Wednesday 02 October 2013
Scientists have uncovered the secrets behind the world’s most common insect repellent – helping them find new ways to protect people from diseases such as malaria, dengue and West Nile fever.
The researchers have used a new screening method to find four insect repellents that are as powerful as DEET, a substance that has been used effectively for more than 60 years to protect people against mosquitoes and other biting insects.
Three have already been deemed safe for human use, and are even found in certain kinds of food. The fourth is a chemical found in the pheromone trails used by ants to find their way home.
Although DEET – diethyl-meta-toluamide – is a highly effective mosquito repellent, it can dissolve man-made fibres and plastics. It is also expensive and inconvenient for use in many parts of Africa, where the need for repellent is greatest.
One of the problems in finding alternatives to DEET is that, until now, scientists have not been sure how the substance works. The study, published in Nature, has however found that DEET triggers a certain kind of nerve receptor called Ir40a, found in the olfactory antenna of insects, which causes them to flee from the chemical’s odour.
Although the work was carried out on fruit flies, the researchers said that the Ir40a receptor is found in the antennae of many other insect pests, such as mosquitoes, head lice and flour beetles. However, the same mechanism does not appear to act as an insect repellent on honey bees, which are commercially important for pollinating crops.
“Until now, no one had a clue about which olfactory receptor insects used to avoid DEET. Without the receptors, it is impossible to apply modern technology to design new repellents,” said Professor Anandasankar Ray, an entomologist at the University of California, Riverside, who led the study.
“Ir40a and its related proteins are conserved not only in flies and mosquitoes, but also in many other insects that are human and plant pests. Our findings could lead to a new generation of cheap, affordable repellents that could protect humans, animals and, in the future, our crops as well,” Professor Ray said.
“We could find truly novel repellents that have remarkable properties such as large-scale spatial protection and long-term protection.”
Once the researchers had been able to identify the critical role of the Ir40a protein in avoiding the odour of DEET, they were able to construct a genetically-engineered insect antenna that glowed fluorescent green in the presence of any airborne substance similar to DEET.
With this method they were able to screen some 500,000 substances for their insect-repellent properties, and found eight that were strong repellents on flies. Four of these proved highly effective against mosquitoes and three were already approved for human consumption, Professor Ray said.
- 1 Mario Balotelli: Staff at arson-hit Manchester Dogs' Home convinced Liverpool striker is behind five-figure donation
- 2 Friends 20th anniversary: Alison Jackson photographs reunited cast
- 3 There is literally not a single woman in this iPhone 6 queue
- 4 Hitler’s former food taster reveals the horrors of the Wolf’s Lair
- 5 Scottish independence: Tory revolt against 'devo max' grows as Rail Minister Claire Perry joins
Daniele Watts: Django Unchained actress detained by Los Angeles police after being mistaken for a prostitute
Scottish independence referendum: A nation divided against itself
Scottish independence: David Cameron is becoming the 'George Bush of Britain'
Russia freezes Ukraine into submission: Kiev admits country doesn't have enough fuel for winter
Scottish independence: The Queen breaks silence on referendum debate – as think tank warns of £14bn black hole if Scotland votes Yes
Archbishop of Canterbury admits doubts about existence of God
£30000 - £35000 per annum: Ashdown Group: Marketing Manager (CIM, B2B, MS Offi...
£22000 - £25000 per annum: Ashdown Group: A highly successful organisation wit...
£1 per day: Randstad Education Leeds: Job Purpose To work closely with the he...
£32000 - £42000 Per Annum: Clearwater People Solutions Ltd: Our client is curr...