Department of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
Malar J. 2010 Feb 8;9:44. doi: 10.1186/1475-2875-9-44.
Scaling up of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) with support from the Global Fund and President's Malaria Initiative is providing increased opportunities for malaria control in Africa. The most cost-effective and longest-lasting residual insecticide DDT is also the most environmentally persistent. Alternative residual insecticides exist, but are too short-lived or too expensive to sustain. Dow Agrosciences have developed a microencapsulated formulation (CS) of the organophosphate chlorpyrifos methyl as a cost-effective, long-lasting alternative to DDT.
Chlorpyrifos methyl CS was tested as an IRS or ITN treatment in experimental huts in an area of Benin where Anopheles gambiae and Culex quinquefasiactus are resistant to pyrethroids, but susceptible to organophosphates. Efficacy and residual activity was compared to that of DDT and the pyrethroid lambdacyalothrin.
IRS with chlorpyrifos methyl killed 95% of An. gambiae that entered the hut as compared to 31% with lambdacyhalothrin and 50% with DDT. Control of Cx. quinquefasciatus showed a similar trend; although the level of mortality with chlorpyrifos methyl was lower (66%) it was still much higher than for DDT (14%) or pyrethroid (15%) treatments. Nets impregnated with lambdacyhalothrin were compromised by resistance, killing only 30% of An. gambiae and 8% of Cx. quinquefasciatus. Nets impregnated with chlorpyrifos methyl killed more (45% of An gambiae and 15% of Cx. quinquefasciatus), but its activity on netting was of short duration. Contact bioassays on the sprayed cement-sand walls over the nine months of monitoring showed no loss of activity of chlorpyrifos methyl, whereas lambdacyhalothrin and DDT lost activity within a few months of spraying.
As an IRS treatment against pyrethroid resistant mosquitoes chlorpyrifos methyl CS outperformed DDT and lambdacyhalothrin. In IRS campaigns, chlorpyrifos methyl CS should show higher, more-sustained levels of malaria transmission control than conventional formulations of DDT or pyrethroids. The remarkable residual activity indicates that cost-effective alternatives to DDT are feasible through modern formulation technology.
在全球基金和总统疟疾倡议的支持下，长效杀虫蚊帐（LLINs）和室内滞留喷洒（IRS）的推广为非洲的疟疾控制提供了更多机会。最具成本效益和最长效的残留杀虫剂滴滴涕也是最具环境持久性的杀虫剂。虽然存在其他替代的残留杀虫剂，但它们的寿命太短或太贵，无法维持。陶氏益农公司开发了一种有机磷毒死蜱甲基的微胶囊制剂（CS），作为滴滴涕的一种具有成本效益、长效的替代品。
在贝宁的一个地区，实验小屋里对毒死蜱甲基 CS 进行了 IRS 或 ITN 处理测试，该地区的冈比亚按蚊和库蚊对拟除虫菊酯具有抗药性，但对有机磷敏感。对其功效和残留活性与滴滴涕和拟除虫菊酯氯菊酯进行了比较。
与氯菊酯处理相比，IRS 处理用毒死蜱甲基处理的进入小屋的冈比亚按蚊死亡率为 95%，而氯菊酯处理为 31%，滴滴涕处理为 50%。对库蚊的控制也呈现出类似的趋势；尽管毒死蜱甲基的死亡率较低（66%），但仍远高于滴滴涕（14%）或拟除虫菊酯（15%）处理。氯菊酯处理的浸渍网因抗药性而受到影响，仅杀死 30%的冈比亚按蚊和 8%的库蚊。用毒死蜱甲基浸渍的网杀死了更多的蚊子（45%的冈比亚按蚊和 15%的库蚊），但其在网眼上的活性持续时间短。在九个月的监测中，对喷洒水泥沙墙上的接触生物测定表明，毒死蜱甲基的活性没有损失，而氯菊酯和滴滴涕在喷洒后几个月内就失去了活性。
作为一种针对拟除虫菊酯抗性蚊子的 IRS 处理方法，毒死蜱甲基 CS 优于滴滴涕和氯菊酯。在 IRS 运动中，毒死蜱甲基 CS 应该显示出比常规滴滴涕或拟除虫菊酯更高、更持久的疟疾传播控制水平。显著的残留活性表明，通过现代配方技术，可以实现滴滴涕的经济有效替代品。
