Optimizing low-technology metofluthrin emanators to extend active ingredient release while maximizing protection against malaria transmission

我们最近开发了一种低技术发射器，由常见的黑森袋浸入广泛使用的挥发性拟除虫菊酯跨氟菊酯，它以蒸汽的形式缓慢释放到空气中。这些发射器在室内和室外保护人类免受行为和生理上具有抵抗力的阿拉伯按蚊的侵害超过2年，并杀死了绝大多数以受保护的人类为食的蚊子。全氟氰菊酯的缺点是其相对较高的熔点，这限制了它在夜间温度非常高的低海拔赤道环境之外的蒸气压力和功效。幸运的是，一种类似安全的挥发性拟除虫菊酯也可以从普通来源获得，这种除虫菊酯熔点较低，因此在与疟疾传播相关的所有温度范围内都保持挥发性。因此，我们建议使用一系列厚度的扩散抑制塑料涂层，使用甲氧氟菊酯而不是转氟菊酯来重复使用这种发射器原型的剂量优化。我们的主要目标是确定最小剂量，以及在该剂量下的最佳涂层厚度，从而提供至少80%的保护，防止接触到蚊子。Arabiens，以及An.冈比亚亚纲和An.福斯特斯，至少一年。我们的次要目标是证明预测的每年最大保护成本与长效杀虫网的成本相当。如果这两个目标都实现了，这项早期研究将应用于进行主要研究：评估使用者和非使用者对疟疾发病率的影响的社区随机对照试验，以及终端用户感知的参与性社会科学研究。这两项研究都将在肯尼亚西部相对高海拔(1100米)、中等温度的地区进行。

We recently developed a low-technology emanator consisting of commonly available Hessian sacking impregnated with the widely-used volatile pyrethroid transfluthrin, which is slowly released into the air as a vapour. These emanators protected humans against behaviourally and physiologically resistant Anopheles arabiensis indoors and outdoors for over 2 years and killed the vast majority of mosquitoes that succeeded in feeding on protected humans. The disadvantage of transfluthrin is its relatively high melting point, which limits its vapour pressure and efficacy outside of low-altitude equatorial settings with very high night time temperatures. Fortunately, a similarly safe volatile pyrethroid called metofluthrin is also available from generic sources, which has a lower melting point so it remains volatile across the full range of temperatures relevant to malaria transmission.We therefore propose to repeat dose-optimization for this emanator prototype with metofluthrin, rather than transfluthrin, using a range of thicknesses of diffusion-retarding plastic coatings. Our primary objective is to identify the minimum dose, and optimal coating thickness at that dose, which confers at least 80% protection against exposure to biting An. arabiensis, as well as An. gambiae and An. funestus, for at least one year. Our secondary objective is to demonstrate that predicted maximum cost per year of protection is comparable with those for long-lasting insecticidal nets.If both objectives are achieved, this early phase study will be followed by an application to conduct the main study: a community-randomized controlled trial to assess impact upon malaria incidence among both users and non-users, supplemented with participatory social science studies of end-user perceptions. Both studies will be conducted in a relatively high altitude (1100m) region of west Kenya with moderate temperatures.