Malaria Consortium-Cameroon Coalition Against Malaria (MC-CCAM), Bastos, PO Box 4256, Yaoundé, Cameroon.
Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon.
Malar J. 2020 May 3;19(1):172. doi: 10.1186/s12936-020-03232-6.
This study evaluated the effectiveness of improved housing on indoor residual mosquito density and exposure to infected Anophelines in Minkoameyos, a rural community in southern forested Cameroon.
Following the identification of housing factors affecting malaria prevalence in 2013, 218 houses were improved by screening the doors and windows, installing plywood ceilings on open eaves and closing holes on walls and doors. Monthly entomological surveys were conducted in a sample of 21 improved and 21 non-improved houses from November 2014 to October 2015. Mosquitoes sampled from night collections on human volunteers were identified morphologically and their parity status determined. Mosquito infectivity was verified through Plasmodium falciparum CSP ELISA and the average entomological inoculation rates determined. A Reduction Factor (RF), defined as the ratio of the values for mosquitoes collected outdoor to those collected indoor was calculated in improved houses (RFI) and non-improved houses (RFN). An Intervention Effect (IE = RFI/RFN) measured the true effect of the intervention. Chi square test was used to determine variable significance. The threshold for statistical significance was set at P < 0.05.
A total of 1113 mosquitoes were collected comprising Anopheles sp (58.6%), Culex sp (36.4%), Aedes sp (2.5%), Mansonia sp (2.4%) and Coquillettidia sp (0.2%). Amongst the Anophelines were Anopheles gambiae sensu lato (s.l.) (95.2%), Anopheles funestus (2.9%), Anopheles ziemanni (0.2%), Anopheles brohieri (1.2%) and Anopheles paludis (0.5%). Anopheles gambiae sensu stricto (s.s.) was the only An. gambiae sibling species found. The intervention reduced the indoor Anopheles density by 1.8-fold (RFI = 3.99; RFN = 2.21; P = 0.001). The indoor density of parous Anopheles was reduced by 1.7-fold (RFI = 3.99; RFN = 2.21; P = 0.04) and that of infected Anopheles by 1.8-fold (RFI = 3.26; RFN = 1.78; P = 0.04). Indoor peak biting rates were observed between 02 a.m. to 04 a.m. in non-improved houses and from 02 a.m. to 06 a.m. in improved houses.
Housing improvement contributed to reducing indoor residual anopheline density and malaria transmission. This highlights the need for policy specialists to further evaluate and promote aspects of house design as a complementary control tool that could reduce indoor human-vector contact and malaria transmission in similar epidemiological settings.
本研究评估了改善住房条件对喀麦隆南部森林地区明科阿梅约斯农村社区室内残留蚊虫密度和感染按蚊暴露的影响。
在 2013 年确定了影响疟疾流行的住房因素后，对 218 所房屋进行了改良，方法是筛选门窗、在露天屋檐上安装胶合板天花板以及封闭墙壁和门上的洞口。2014 年 11 月至 2015 年 10 月，在 21 所改良房屋和 21 所非改良房屋中每月进行一次昆虫学调查。从夜间在人类志愿者身上采集的蚊虫进行形态学鉴定，并确定其生殖状态。通过疟原虫环子孢子蛋白 ELISA 验证蚊虫的感染力，并确定平均昆虫接种率。改良房屋（RFI）和非改良房屋（RFN）中的减少因子（RF）定义为室外采集的蚊虫数量与室内采集的蚊虫数量的比值。干预效果（IE=RFI/RFN）衡量了干预的真实效果。卡方检验用于确定变量的显著性。统计显著性的阈值设定为 P<0.05。
共采集了 1113 只蚊虫，包括按蚊（58.6%）、库蚊（36.4%）、伊蚊（2.5%）、曼蚊（2.4%）和库蚊（0.2%）。按蚊中包括冈比亚按蚊复合体（95.2%）、致倦库蚊（2.9%）、兹氏按蚊（0.2%）、布氏按蚊（1.2%）和沼泽按蚊（0.5%）。仅发现冈比亚按蚊按蚊种。该干预措施使室内按蚊密度降低了 1.8 倍（RFI=3.99；RFN=2.21；P=0.001）。有生殖力的按蚊室内密度降低了 1.7 倍（RFI=3.99；RFN=2.21；P=0.04），感染按蚊室内密度降低了 1.8 倍（RFI=3.26；RFN=1.78；P=0.04）。在非改良房屋中，室内峰值叮咬率出现在凌晨 02 点至 04 点之间，而在改良房屋中则出现在凌晨 02 点至 06 点之间。
住房改善有助于降低室内残留按蚊密度和疟疾传播。这凸显了政策专家进一步评估和推广房屋设计方面的必要性，因为这可能是一种补充控制工具，可以减少类似流行病学环境中室内人类与媒介的接触和疟疾传播。
