Olyset™ Plus is a 2nd generation long-lasting insecticidal net (LLIN) containing 2% of the pyrethroid insecticide permethrin and 1% of the synergist piperonyl butoxide (PBO).
All insects, whether susceptible or resistant, have enzymes that can metabolise insecticides into harmless components. Some of these enzymes, known as cytochrome P450s, are powerful oxidising agents that can detoxify an active ingredient before the desired effect is achieved; PBO is an inhibitor of these enzymes and therefore blocks this action.
In metabolic resistant insects the activity of these enzymes can be greatly enhanced which can significantly reduce the efficacy of insecticides. PBO acts on these enzymes in resistant insects and inhibits the breakdown or the metabolism of pyrethroids, rendering the insecticide more effective. PBO also increases the activity of pyrethroids to susceptible insects, so adding PBO to an LLIN has a benefit even in areas where there is no resistance.
Olyset Plus has been designed with both insecticide and synergist incorporated in all net fibres. Sumitomo Chemical controlled-release technology releases the two ingredients at a constant ratio of 2:1 to ensure enhanced efficacy against all mosquitoes, including those which have metabolic resistance to pyrethroids.
Research & Reports
A cluster randomized controlled trial by Nagasaki University on Olyset Plus LN, a long-lasting net incorporating the synergist Piperonyl Butoxide (PBO), resulting in reduced risk of malaria in children in Western Kenya in an area where mosquito vectors with metabolic resistance predominate, causing high levels of pyrethroid resistance.
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1 Effectiveness of a long-lasting piperonyl butoxide-treated insecticidal net and indoor residual spray interventions, separately and together, against malaria transmitted by pyrethroid-resistant mosquitoes: a cluster, randomised controlled, two-by-two factorial design trial. Natacha Protopopoff et al Lancet 2018;391, 1577-1588
Effect of long-lasting insecticidal nets with and without piperonyl butoxide on malaria indicators in Uganda (LLINEUP): a pragmatic, cluster-randomised trial embedded in a national LLIN distribution campaign. Sarah G Staedke et al Lancet 2020; 395:1292–303
11 Page 59 in the 13th WHOPES Working Group Meeting, WHO/HQ, Geneva, 28-30 July 2009