Wageningen University and Research, Wageningen, The Netherlands.
College of Medicine, University of Malawi, Zomba, Malawi.
Parasit Vectors. 2018 Jul 3;11(1):383. doi: 10.1186/s13071-018-2977-3.
Most people infected with malaria acquire the infection indoors from mosquito vectors that entered the house through open eaves, windows and doors. Structural house improvement (e.g. closed eaves and screened windows) is an established method of reducing mosquito entry. It could be complementary to other interventions such as insecticide-treated bed nets (ITNs) for malaria control because it covers and protects all individuals in a house equally. However, when implemented at a large scale, house improvement may not be employed optimally. It is therefore critical to assess whether partial house improvement will have any effect on mosquito house entry. We investigated the effect of partial and complete eave closure on the house-entry rates of malaria vectors and other mosquitoes in southern Malawi.
The study was conducted for 25 nights in May-June 2016. Twenty-five traditional houses were modified according to five treatments: fully closed eaves, three different levels of partially closed eaves, and open eaves. All houses had fully screened windows and closed doors. Host-seeking mosquitoes were sampled inside these houses using Centers for Disease Control and Prevention (CDC) light traps. The effect of open eaves versus partial or complete eave closure on the number of mosquitoes trapped inside the house was estimated using a generalized linear mixed model fitted with Poisson distribution and a log-link function.
House entry by malaria vectors was 14-times higher in houses with fully open eaves compared to houses with fully closed eaves adjusting for wall-type, number of people that slept in the house the previous night, cooking locations and presence of livestock. Houses with four small openings had 9 times more malaria vectors compared to houses with fully closed eaves. The catches of culicine mosquitoes caught in houses with fully closed eaves were not different from those caught in houses with the other treatments.
Closed eaves resulted in fewer malaria vectors in houses, with differences depending on the degree of eave closure. The ability of malaria vectors to locate any remaining entry points on improved houses, as demonstrated here, suggests that quality control must be an important component of implementing house improvement as an intervention.The lack of effect on culicine mosquitoes in this study could reduce acceptance of house improvement, as implemented here, by household residents due to continued nuisance biting. This limitation could be addressed through community engagement (e.g. encouraging people to close their doors early in the evenings) or improved designs.
大多数感染疟疾的人都是在室内从进入房屋的蚊子媒介感染的，蚊子通过敞开的屋檐、窗户和门进入室内。结构性房屋改进（例如封闭的屋檐和有纱窗的窗户）是减少蚊子进入的一种既定方法。它可以与其他干预措施（例如经杀虫剂处理的蚊帐）相结合，以控制疟疾，因为它可以平等地覆盖和保护房屋中的所有人员。但是，当大规模实施时，房屋改进可能无法得到最佳利用。因此，评估部分房屋改进是否会对蚊子进入房屋产生任何影响至关重要。我们在马拉维南部调查了部分和完全封闭屋檐对疟疾媒介和其他蚊子进入房屋的影响。
本研究于 2016 年 5 月至 6 月进行了 25 晚。根据五种处理方法对 25 座传统房屋进行了修改：完全封闭的屋檐、三种不同程度的部分封闭屋檐和敞开的屋檐。所有房屋都有完全屏蔽的窗户和关闭的门。使用疾病控制和预防中心（CDC）的诱蚊灯在这些房屋内采样寻找宿主的蚊子。使用广义线性混合模型，通过泊松分布和对数链接函数，估计开放屋檐与部分或完全封闭屋檐对屋内捕获蚊子数量的影响。
与完全封闭屋檐的房屋相比，完全开放屋檐的房屋内捕获的疟疾媒介数量高出 14 倍，调整了墙壁类型、前一晚睡在屋内的人数、做饭地点和牲畜存在的因素。与完全封闭屋檐的房屋相比，有四个小开口的房屋捕获的疟疾媒介高出 9 倍。完全封闭屋檐房屋内捕获的库蚊数量与其他处理方法捕获的数量没有差异。
封闭的屋檐减少了房屋内的疟疾媒介，其效果取决于屋檐封闭的程度。疟疾媒介能够定位到改进房屋上任何剩余的进入点，这表明质量控制必须是实施房屋改进作为干预措施的重要组成部分。本研究中对库蚊没有影响可能会降低家庭居民对房屋改进的接受程度，因为持续的骚扰叮咬。可以通过社区参与（例如，鼓励人们在傍晚早些时候关门）或改进设计来解决这一限制。
