 2.4 Interventions to be trialed Olyset plus Sumitomo Chemicals is a LLIN containing the pyrethroid permethrin and the synergist piperonyl butoxide PBO as the active ingredients AI.Nets combining insecticide plus PBO are able to control mosquitoes whose resistance is based on oxidative metabolism. Olyset net is a long established LLIN that contains permethrin but no synergist. Both LLINs are approved by WHOPES and registered in Tanzania. In experimental hut trials in West Africa, Olyset Plus killed twice as many resistant mosquitoes and reduced biting rates by one third as compared to Olyset. On exposure to the two types of LLIN for 3 minutes none of the An. gambiae mosquitoes collected from Muleba was killed by the conventional Olyset but all were killed by Olyset Plus. This indicates the type of resistance occurring in Muleba can be synergised by the PBO on Olyset Plus. This new LLIN has the potential to restore control of malaria transmitted by resistant mosquito populations. 