Not only do bed nets help protect people against mosquito bites, but if those nets are treated with an insecticide, they also kill any of the insects that touch them. A simple new technology could make such nets much more lethal to mosquitoes, yet also safer for humans.
Utilizing video tracking systems developed with engineers from the University of Warwick, scientists at Britain's Liverpool School of Tropical Medicine started by analyzing the manner in which mosquitoes fly around conventional bed nets. What they found was that the insects spend a lot of time over top of the nets, flying back and forth.
In order to place an obstacle in that flight path, the researchers developed what's known as the Barrier Bednet. There's actually not much to the device, as it's simply a rectangular panel of insecticide-treated netting that protrudes vertically from the top of a conventional bed net. It very much gets in the mosquitoes' way, though.
This causes them to collide with it, exposing a greater total number of insects to the insecticide. In fact, field tests conducted in Burkina Faso showed the Barrier Bednet to be highly effective at killing malaria-spreading Anopheles gambiae mosquitoes. This was the case even when only it, and not the rest of the bed net, was treated with insecticide.
That's an important consideration, given that mosquitoes are becoming increasingly resistant to the traditionally-used pyrethroid class of insecticides. As a result, harsher and potentially more human-unfriendly insecticides may be needed. If those can be located up and away from peoples' beds – on the Barrier Bednet – there's less chance of those people being exposed to them.
"This paves the way to use insecticides previously unavailable for bed nets because of possible health risks from direct contact," says Liverpool's Prof. Philip McCall, leader of the study. "Plus, if we only use the effective insecticide on the barrier panel, it means that manufacturing nets would cost a lot less, as would the over-the-counter price for the people that need them. It also means we could consider additional insecticides that might have been ruled out previously as too expensive."
The research is described in a paper that was recently published in the journal Nature Microbiology.