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

Science Editor

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.

Suggested Topics
News
people
Arts and Entertainment
Joel Edgerton, John Turturro and Christian Bale in Exodus: Gods and Kings
film Ridley Scott reveals truth behind casting decisions of Exodus
News
people
Sport
footballArsenal 2 Borussia Dortmund 0: And they can still top the group
PROMOTED VIDEO
Arts and Entertainment
An unseen image of Kurt Cobain at home featured in the film 'Kurt Cobain: Montage of Heck'
filmThe singers widow and former bandmates have approved project
News
Andy Murray with his girlfriend of nine years, Kim Sears who he has got engaged to
peopleWimbledon champion announces engagement to girlfriend Kim Sears
Arts and Entertainment
Jake Quickenden and Edwina Currie are joining the I'm A Celebrity...Get Me Out Of Here! camp
tv
Arts and Entertainment
George Mpanga has been shortlisted for the Critics’ Choice prize
music
News
Albert Camus (left) and Jean-Paul Sartre fell out in 1952 and did not speak again before Camus’s death
people
Arts and Entertainment
Roisin, James and Sanjay in the boardroom
tvReview: This week's failing project manager had to go
News
ebooksNow available in paperback
News
Ed Miliband visiting the Holocaust museum in Jerusalem. The Labour leader has spoken more openly of his heritage recently
newsAttacks on the Labour leader have coalesced around a sense that he is different, weird, a man apart. But are the barbs more sinister?
Arts and Entertainment
'Felfie' (2014) by Alison Jackson
photographyNew exhibition shows how female creatives are changing the way women are portrayed in advertising
News
i100
Life and Style
Fright night: the board game dates back to at least 1890
life
Environment
The vaquita is being killed by fishermen trying to catch the totoaba fish, which is prized in China
environmentJust 97 of the 'world's cutest' sea mammals remain
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Ashdown Group: Data Warehouse & Business Intelligence Co-ordinator

£35000 per annum: Ashdown Group: Required skills include SQL querying, SSRS, u...

Ashdown Group: C#.Net Developer - C#, ASP.Net, PHP, HTML, JavaScript, CSS

£30000 - £35000 per annum: Ashdown Group: C#.Net Developer - C#, ASP.Net, HTML...

Argyll Scott International: Senior Business Analyst- Insurance

Negotiable: Argyll Scott International: Senior Business Analyst - Insurance ...

Recruitment Genius: Property Manager

£25000 - £29000 per annum: Recruitment Genius: This independent, growing Sales...

Day In a Page

Cameron, Miliband and Clegg join forces for Homeless Veterans campaign

Cameron, Miliband and Clegg join forces for Homeless Veterans campaign

It's in all our interests to look after servicemen and women who fall on hard times, say party leaders
Millionaire Sol Campbell wades into wealthy backlash against Labour's mansion tax

Sol Campbell cries foul at Labour's mansion tax

The former England defender joins Myleene Klass, Griff Rhys Jones and Melvyn Bragg in criticising proposals
Nicolas Sarkozy returns: The ex-President is preparing to fight for the leadership of France's main opposition party – but will he win big enough?

Sarkozy returns

The ex-President is preparing to fight for the leadership of France's main opposition party – but will he win big enough?
Is the criticism of Ed Miliband a coded form of anti-Semitism?

Is the criticism of Miliband anti-Semitic?

Attacks on the Labour leader have coalesced around a sense that he is different, weird, a man apart. But is the criticism more sinister?
Ouija boards are the must-have gift this Christmas, fuelled by a schlock horror film

Ouija boards are the must-have festive gift

Simon Usborne explores the appeal - and mysteries - of a century-old parlour game
There's a Good Girl exhibition: How female creatives are changing the way women are portrayed in advertising

In pictures: There's a Good Girl exhibition

The new exhibition reveals how female creatives are changing the way women are portrayed in advertising
UK firm Biscuiteers is giving cookies a makeover - from advent calendars to doll's houses

UK firm Biscuiteers is giving cookies a makeover

It worked with cupcakes, doughnuts and macarons so no wonder someone decided to revamp the humble biscuit
Can SkySaga capture the Minecraft magic?

Can SkySaga capture the Minecraft magic?

It's no surprise that the building game born in Sweden in 2009 and now played by millions, has imitators keen to construct their own mega money-spinner
The King's School is way ahead of the pack when it comes to using the latest classroom technology

Staying connected: The King's School

The school in Cambridgeshire is ahead of the pack when it comes to using the latest classroom technology. Richard Garner discovers how teachers and pupils stay connected
Christmas 2014: 23 best women's perfumes

Festively fragrant: the best women's perfumes

Give a loved one a luxe fragrance this year or treat yourself to a sensual pick-me-up
Arsenal vs Borussia Dortmund: Alex Oxlade-Chamberlain celebrates century with trademark display of speed and intuition

Arsenal vs Borussia Dortmund

The Ox celebrates century with trademark display of speed and intuition
Billy Joe Saunders vs Chris Eubank Jnr: When two worlds collide

When two worlds collide

Traveller Billy Joe Saunders did not have a pampered public-school upbringing - unlike Saturday’s opponent Chris Eubank Jnr
Homeless Veterans Christmas Appeal: Drifting and forgotten - turning lives around for ex-soldiers

Homeless Veterans Christmas Appeal: Turning lives around for ex-soldiers

Our partner charities help veterans on the brink – and get them back on their feet
Putin’s far-right ambition: Think-tank reveals how Russian President is wooing – and funding – populist parties across Europe to gain influence in the EU

Putin’s far-right ambition

Think-tank reveals how Russian President is wooing – and funding – populist parties across Europe to gain influence in the EU
Tove Jansson's Moominland: What was the inspiration for Finland's most famous family?

Escape to Moominland

What was the inspiration for Finland's most famous family?