Insecticide treated eave nets and window screens for malaria control

长效杀虫蚊帐(LLIN)是疟疾控制的一个关键组成部分，可挽救许多人的生命；但它们有几个缺点。生活在疟疾流行地区的大约一半的人无法获得LLIN。造成这一赤字的部分原因是蚊帐交付不足，但一个主要因素是LLIN迅速遭到破坏，导致其寿命低于预期的3年。此外，在家庭内部的某些群体中，蚊帐的分配通常是不平等的。例如，虽然最小的儿童及其母亲可能睡在蚊帐下，但学龄儿童获得蚊帐的机会往往很少。即使是那些能够接触到蚊帐的人，也只有在睡觉时才会受到保护。我们提出了一种新的工具制作的杀虫剂处理的屋檐网(ITEN)和杀虫剂处理的窗纱(ITWS)用于全屋筛查。ITEN是一种特制的网卷，当地团队使用锤子和钉子在30分钟内将网卷贴在屋顶外挑的房子上和窗户上。与LLIN相比，这些干预措施至少有三个潜在的优势：它们保护家庭中的每个人；当他们在家庭中时，他们一直在保护他们；LLIN可能比LLIN更耐用，提供长达5年的保护，使它们具有极高的成本效益(每户每年比LLIN低1.75美元)。固定在家庭结构屋檐上的ITEN和窗户上的ITW阻止进入并在进入房屋的主要接入点杀死按蚊。蚊子被吸引到房子里，试图从屋檐或窗户进入，并会在干预中遇到杀虫剂，把房子变成了一种“诱杀”，这不仅保护了房子里的人，也保护了社区的每个人。2012-14年度对肯尼亚西部80户家庭的ITEN和ITWS进行的初步家庭随机评估显示，与只使用LLIN的家庭相比，使用ITEN、ITWS和LLIN的家庭中的媒介蚊子减少了75%。ITEN和ITWS已经可用和可扩展，可以适用于任何类型的家庭。在杀虫剂应用方面，ITEN和ITWS比LLIN具有优势。LLIN每天都会被触摸并定期清洗，这限制了可以使用的化学品的范围。ITEN和ITWS与更广泛的杀虫剂兼容。这将是非常有利的，因为在非洲，由于蚊子抗药性的增长，用于控制疟疾的杀虫剂正在变得不那么有效--特别是因为抗药性是当地的一种现象：在一个地方有效的化学物质在另一个地方可能无效，因此拥有广泛的杀虫剂选择至关重要。此外，ITEN和ITWS可以由更致密、更耐用的材料制成。这不仅使它们在身体上更耐用，还允许更多的杀虫剂被注入，杀死更多蚊子，甚至是抗药性蚊子，并使效果持续更长时间。我们建议在适当的时候在坦桑尼亚进行一项大规模的流行病学终点群组随机试验。然而，在这之前，有必要调查哪种特定的杀虫剂组合适合当地条件。我们还希望进行一项研究，以评估将ITEN和ITWS适合当地家庭的可行性，以及当地社区对它们的接受程度。因此，我们正为两项小型初步研究申请发展拨款：一项是在试验性小屋进行，以比较两种不同杀虫剂的ITEN和ITWS产品在当地情况下的家庭和社区保护效果，以确定哪种产品更适合进行大规模试验；第二项研究为200户本地家庭安装ITEN和ITWS，并在一年后进行跟进，以评估安装的便利性和成本、寿命和社区接受程度。

Long lasting insecticidal nets (LLIN) are a key component of malaria control and are responsible for saving many lives; but they have several drawbacks. About half of people living in malaria endemic areas do not have access to LLINs. Some of this deficit is due to insufficient delivery of nets, but a major factor is LLINS becoming rapidly damaged, resulting in a lifespan less than their intended 3-years. Additionally, there is typically an unequal distribution of nets to certain groups within households. For example, while the youngest children and their mothers are likely to sleep under nets, school age children often have very low access to nets. And even those who do have access to nets are only protected when they are sleeping. We propose a new tool - purpose made insecticide-treated eave nets (ITENs) with insecticide treated window screens (ITWS) for full house screening. ITENs are purpose made netting rolls that are applied to the house under the overhang of the roof and across windows within 30 minutes by local teams using hammer and nails. These interventions have at least three potential advantages over LLINs: they protect everybody in the household; they protect them at all times when they are in the household; and the are potentially much more durable than LLINs, giving up to 5 years' protection and making them highly cost effective (up to $1.75 per year per household less than LLINs). ITENs fixed across the eaves of household structures and ITWS on the windows block access to and kill Anopheles mosquitoes at their main access points into houses. Mosquitoes are attracted to houses, try to enter through the eaves or windows, and will come up against insecticides in the interventions, turning the house into a "lure and kill", that not only protect people in the house but also everyone in the community. Preliminary household randomised evaluation of ITENs and ITWS among 80 households in Western Kenya in 2012-14 showed 75% fewer vector mosquitoes in the houses using ITENs, ITWS and LLINs when compared to households using LLINs only. ITENs and ITWS are already available and scalable and can be fitted to any type of house.ITENs and ITWS have advantages over LLINs for the application of insecticides. LLINS are touched daily and washed regularly, limiting the range of chemicals which can be applied. ITENs and ITWS are compatible with a wider range of insecticides. This will be greatly advantageous because insecticides used for malaria control are becoming less effective in Africa due to the growing resistance of mosquitoes - and particularly because resistance is a local phenomenon: chemicals that work in one place may be ineffective in another so it is vital to have a wide choice of insecticides. In addition, ITENs and ITWS can be made from denser, more durable material. This not only makes them more physically durable but allows a greater quantity of insecticide to be impregnated, killing more mosquitoes, even resistant ones, and making the effect last longer. We propose in due course to undertake a large-scale cluster randomised trial with epidemiological endpoints in Tanzania. However, before this is possible it is necessary to investigate which particular combination of insecticides, is appropriate to the local conditions. We also wish to undertake a study to assess how feasible it is to fit ITENs and ITWS to local houses and how acceptable local communities find them. We are therefore applying for a development grant for a 2 small preliminary studies: one in experimental huts, which will be conducted to compare the household and community protective efficacy of 2 ITEN and ITWS products with different insecticides in local conditions to see which is better to take forward to a large scale trial; and a second in which 200 local houses are fitted with ITENs and ITWS and followed up after 1 year to assess ease and cost of fitting, longevity and community acceptability.