Why a lucky few escape bug bites

ARE you left unscathed while those around you get covered in mosquito bites? It’s probably because you produce natural mosquito repellents. The good news for the rest of us is that sprays and lotions containing these natural chemicals could soon be available.

“We’ve got 11 key compounds, but there are a few more,” says John Pickett of Rothamsted Research in Harpenden in the UK. His team first identified people who are less likely to be bitten by Aedes aegypti mosquitoes, which can transmit yellow fever. Pickett’s colleague James Logan then collected whole-body odours from these individuals and isolated the most potent repellents with the help of a Y-shaped apparatus that gives mosquitoes the choice of flying towards or away from odours. Pickett will not name the chemicals until they are patented.Together with the Danish Institute of Agricultural Sciences in Copenhagen, the team has also isolated natural substances that some cows produce to repel flies. The most potent is 6-methyl-5-heptene-2-one.(Source: Medical and Veterinary Entomology, vol 18, p 313, From issue 2483 of New Scientist magazine, 22 January 2005, page 17, January 2005)