Oxborough Richard M, Kitau Jovin, Jones Rebecca, Mosha Franklin W, Rowland Mark W
Department of Disease Control, London School of Hygiene and Tropical Medicine (LSHTM), London, UK.
Parasit Vectors. 2014 Oct 2;7:454. doi: 10.1186/s13071-014-0454-1.
The Stockholm Convention on Persistent Organic Pollutants (POPs) came into effect in 2004; the use of DDT for malaria control has been allowed to continue under exemption since then due to a perceived absence of equally effective and efficient alternatives. Alternative classes of insecticide for indoor residual spraying (IRS) have a relatively short residual duration of action (2-6 months according to WHO). In areas of year-round transmission multiple spray cycles are required, resulting in significantly higher costs for malaria control programs and user fatigue. This study evaluated performance of a new formulation of deltamethrin (pyrethroid) with polymer (SC-PE) to prolong the effective residual action to >6 months.
Deltamethrin SC-PE was evaluated alongside an existing water dispersible granule (WG) formulation and DDT water dispersible powder (WP) in laboratory and hut bioassays on mud, concrete, palm thatch and plywood substrates. An experimental hut trial was conducted in Lower Moshi Rice Irrigation Zone, Tanzania from 2008-2009 against wild, free-flying, pyrethroid susceptible An. arabiensis. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Bioassays were carried out monthly on sprayed substrates to assess residual activity.
Bioassays in simple huts (designed for bioassay testing only) and experimental huts (designed for testing free flying mosquitoes) showed evidence that SC-PE improved longevity on mud and concrete over the WG formulation. Both deltamethrin SC-PE and WG outperformed DDT in bioassays on all substrates tested in the laboratory and simple huts. In experimental hut trials SC-PE, WG and DDT produced high levels of An. arabiensis mortality and the treatments were equivalent over nine months' duration. Marked seasonal changes in mortality were recorded for DDT and deltamethrin treatments, and may have been partly influenced by outdoor temperature affecting indoor resting duration of mosquitoes on sprayed surfaces, although no clear correlation was demonstrated.
There is a limited range of alternative insecticides for IRS, and deltamethrin SC-PE is likely to have an important role as part of a rotation strategy with one or more different insecticide classes rotated annually, particularly in areas that currently have low levels of pyrethroid resistance or low LLIN coverage and year-round malaria transmission.
《关于持久性有机污染物的斯德哥尔摩公约》于2004年生效；自那时起，由于认为缺乏同样有效和高效的替代品，滴滴涕用于疟疾控制的使用被允许继续豁免。用于室内滞留喷洒（IRS）的替代类杀虫剂的残留作用持续时间相对较短（根据世界卫生组织的数据为2 - 6个月）。在全年传播的地区，需要多个喷洒周期，这导致疟疾控制项目的成本显著增加以及用户疲劳。本研究评估了一种含有聚合物的新型溴氰菊酯制剂（SC - PE）将有效残留作用延长至>6个月的性能。
在实验室以及泥地、混凝土、棕榈茅草和胶合板基质的小屋生物测定中，对溴氰菊酯SC - PE与现有的水分散粒剂（WG）制剂以及滴滴涕水分散粉剂（WP）进行了评估。2008 - 2009年在坦桑尼亚的下莫希水稻灌溉区进行了一项实验小屋试验，针对野生、自由飞行、对拟除虫菊酯敏感的阿拉伯按蚊。根据杀虫剂引起的死亡率和吸血抑制来衡量性能。每月对喷洒的基质进行生物测定以评估残留活性。
在简易小屋（仅设计用于生物测定测试）和实验小屋（设计用于测试自由飞行的蚊子）中的生物测定表明，有证据显示SC - PE在泥地和混凝土上的持效期比WG制剂更长。在实验室和简易小屋中测试的所有基质的生物测定中，溴氰菊酯SC - PE和WG的表现均优于滴滴涕。在实验小屋试验中，SC - PE、WG和滴滴涕均产生了高水平的阿拉伯按蚊死亡率，并且在九个月的时间内这些处理效果相当。记录到滴滴涕和溴氰菊酯处理的死亡率有明显的季节性变化，这可能部分受到室外温度影响蚊子在喷洒表面的室内栖息时间的影响，尽管未显示出明确的相关性。
用于IRS的替代杀虫剂种类有限，溴氰菊酯SC - PE作为每年与一种或多种不同杀虫剂类别轮换的轮换策略的一部分可能具有重要作用，特别是在目前拟除虫菊酯抗性水平较低或长效驱虫蚊帐覆盖率较低且全年有疟疾传播的地区。
