Bernier and his team developed the repellants with what they say is the first successful application of a computer model using the molecular structures of more than 30,000 chemical compounds tested as repellants over the last 60 years.

Using 11 known compounds, they synthesised 23 new ones. Of those, 10 gave about 40 days protection, compared to 17.5 days for DEET, when a soaked cloth was worn by a human volunteer. When applied to the skin, however, DEET lasts about five hours.

'If the mosquitoes don't even land, we know the repellent is surely working,' he explained. 'If they walk around on the cloth-covered-arm, they are on the verge of being repelled. If they bite... on to the next repellent,' Bernier said, according to a CMAVE release.

These results were presented Monday at the 238th National Meeting of the American Chemical Society (ACS).