London: Ever wondered why some people get bitten more than others by mosquitoes? Well, the answer lies in their sweat, say researchers.
A new study has revealed that people whose sweat smells sweet are less vulnerable to insect bites as compared to those who have lower levels of fruity smelling compounds in their sweat.
According to the researchers, these compounds known as ketones actually repel mosquitoes -- and that's why people who produce high levels are less likely to be bitten.
Lead researcher Dr James Logan of Rothamsted Research was quoted by 'The Daily Telegraph' as saying: "Mosquitoes can detect a wide range of different chemicals and signals to help them identify something as a human being.
"The higher concentrations of these ketones seems to trick the mosquitoes into thinking what they are smelling is not a human. It could be that these chemicals carry a message about the people who produce them that makes them unattractive to mosquitoes."
Logan and colleagues at Aberdeen University analysed the body odours produced by a panel of volunteers found to be resistant to mosquitoes and compared them with the body odours of those who attracted the insects to reach the conclusion.
The subjects were all asked to stick to strict diets, not to drink alcohol and avoid using perfumes and deodorant so their natural body odour could be collected.
The study found five ketones that were effective at repelling the mosquitoes and when they were sprayed on skin of volunteers who were normally attractive to mosquitoes, insects were repelled.
An estimated 700 million people every year catch mosquito-borne diseases worldwide. And, the researchers are now developing a new kind of insect repellent for those whose bodies don't smell fruity.
In fact, tests carried out in Kenya and Brazil, where mosquitoes can transmit malaria and yellow fever, have proved "very effective". They have also found the chemicals are just as effective against the notorious Scottish midges and ticks.
"We have been testing these chemicals on the skin to see how effective they are as repellents and have shown they are effective against three different species of mosquito," Dr Logan said.