Mosquitoes can rapidly develop resistance to bed nets treated with insecticide, a study from Senegal says.In recent years the nets have become a leading method of preventing malaria, especially in Africa.In the Lancet Infectious Diseases, the researchers also suggest the nets reduced the immunity of older children and adults to malaria infection.

But other experts say the study was too small to draw conclusions about the long-term effectiveness of nets.

Read more, via BBC News.