Mosquitoes were drawn to smelly socks.
A new trap for malaria-spreading mosquitoes using the odor of human feet to lure them in is being developed by scientists in Tanzania.
The traps are thought to attract up to four times as many mosquitoes as to humans themselves, then kill the bloodsucking creatures with a lethal dose of insecticide.
Combined with the use of mosquito nets and mosquito repellents, it is hoped they could drastically reduce the transmission rate of malaria, one of the biggest killers in the developing world.
Scientists first came up with the idea after seeing how mosquitoes were drawn to smelly socks.
They persuaded a number of volunteers to donate socks they had worn for at least ten hours. They then placed them inside canvas and wooden boxes hung with insecticide-laced drapes outside people’s homes in rural southeast Tanzania.
Dr Fredros Okumu is leading the two-year project funded by the Bill and Melinda Gates Foundation and Grant Challenges Canada at the Ifakara Health Institute in Tanzania.
He said mosquitoes work through smell rather than sight so could not tell the difference between the trap and real humans before it was too late.
“In their attempts to get blood from these devices, between 74 to 95 per cent of all of those who landed in them got killed,” he said. “We’re hoping this will be a worthwhile and significant addition to the malaria control arsenal.”
The scientists now want to establish whether socks themselves or a synthetic version of their smell work best and whether the devices cut the number of times people are bitten. They also plan to simplify the devices enough to be made and sold by the villagers themselves.
Each year, there are almost 250 million new cases of malaria and almost 800,000 people – mostly children under five and pregnant women – die, according to the World Health Organisation.