A deltamethrin crystal polymorph for more effective malaria control
A deltamethrin crystal polymorph for more effective malaria control
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DOI：
10.1073/pnas.2013390117
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发表时间：
2020-10-27
影响因子：
11.1
通讯作者：
Kahr, Bart
中科院分区：
文献类型：
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作者：
Yang, Jingxiang;Erriah, Bryan;Kahr, Bart
拟除虫菊酯接触杀虫剂是疟疾控制的主要手段，但由于按蚊种群对杀虫剂的普遍耐药性，其效力正在下降，这是一个重大的公共卫生挑战。为克服这一挑战提出了若干战略，包括具有新作用模式的杀虫剂。然而，在低收入国家使用新杀虫剂可能很昂贵。在这里，我们报告了一种简单而廉价的方法，以提高溴氰菊酯，最活跃和最常用的拟除虫菊酯，对按蚊的效力超过10倍。在加热仅几分钟后，市售溴氰菊酯晶体（I型）熔化并在冷却后结晶成多晶型物（II型），其对果蝇和蚊子的作用快得多。流行病学模型表明，在室内滞留喷洒中使用II型而不是I型，即使在抗药性很强的情况下，也能显著抑制疟疾的传播。II型的简单制备，加上其动力学稳定性和显著更高的功效，认为II型可以为面临全球拟除虫菊酯耐药性而失去保护的低收入国家提供有力、及时和负担得起的疟疾控制解决方案。
Pyrethroid contact insecticides are mainstays of malaria control, but their efficacies are declining due to widespread insecticide resistance in Anopheles mosquito populations, a major public health challenge. Several strategies have been proposed to overcome this challenge, including insecticides with new modes of action. New insecticides, however, can be expensive to implement in low-income countries. Here, we report a simple and inexpensive method to improve the efficacy of deltamethrin, the most active and most commonly used pyrethroid, by more than 10 times against Anopheles mosquitoes. Upon heating for only a few minutes, the commercially available deltamethrin crystals, form I, melt and crystallize upon cooling into a polymorph, form II, which is much faster acting against fruit flies and mosquitoes. Epidemiological modeling suggests that the use of form II in indoor residual spraying in place of form I would significantly suppress malaria transmission, even in the presence of high levels of resistance. The simple preparation of form II, coupled with its kinetic stability and markedly higher efficacy, argues that form II can provide a powerful, timely, and affordable malaria control solution for low-income countries that are losing protection in the face of worldwide pyrethroid resistance.