April 7, 2009
New insecticides may stall malaria forever
A U.S.-led study suggests insecticides that would kill just older mosquitoes would be a better way of controlling malaria.
Pennsylvania State University Professor Andrew Read said such an approach would be a more sustainable way of controlling the disease and might lead to evolution-proof insecticides that never become obsolete.
Each year malaria kills about a million people, but many of the chemicals used to kill the insects become ineffective, the scientists said, since repeated exposure to an insecticide breeds a new generation of mosquitoes that are resistant to that particular chemical.
Insecticides sprayed on house walls or bed nets are some of the most successful ways of controlling malaria, said Read.
But they work by killing the insects or denying them the human blood they turn into eggs. This imposes an enormous selection in favor of insecticide-resistant mosquitoes.
Read, Penn State Professor Matthew Thomas and doctoral student Penelope Lynch of The Open University in the United Kingdom say chemical or biological insecticides that kill only older mosquitoes are a more effective way to fight the deadly disease.
It is one of the great ironies of malaria, said Read.
Most mosquitoes do not live long enough to transmit the disease. To stop malaria, we only need to kill the old mosquitoes.
The research appears in the journal PLoS Biology.