THE EFFECT OF SCREENING DOORS AND WINDOWS ON INDOOR MALARIA TRANSMISSION, AND ITS DURABILITY AND COMMUNITY ACCEPTANCE IN ARBA MINCH TOWN, SOUTHWESTERN ETHIOPIA: A RANDOMIZED TRIAL

Abstract

There is a reduction in the burden of malaria globally due to extensive application of bed nets, indoor residual spraying, effective drugs and diagnostic tools. To sustain the gain and accelerate the current reduction, there is a need for locally adapted effective, sustainable and community accepted supplementary intervention. Growing evidence suggests that improving housing reduce indoor density of vectors and incidence of malaria. This study assessed the effect of house screening intervention on indoor malaria transmission, and its durability, and community acceptance. A randomized control trial with two arms (houses with screened doors and windows and without these interventions) was conducted in Arba Minch Town, southwestern Ethiopia. Both epidemiological and entomological data were collected to evaluate the impact of screening doors and windows on incidence of malaria and indoor density of malaria vectors. The frequency of damage to different structure of screening was measured in two round examinations with pre-prepared checklist. In-depth interviews with semi-structured questioner in Amharic language were conducted with purposely selected household heads from intervention group. A total of 477 participants, 50.1% (n = 239) inhabitants of screened houses and 49.9% (n= 238) inhabitants of unscreened houses, were followed for six months. Of 45 microscopically confirmed clinical malaria cases, 80 % (n = 36) were Plasmodium falciparum whereas the rest 20 % (n = 9) were Plasmodium vivax. The incidence of P. falciparum malaria was low [Incidence Rate Ratio (IRR) 0.39, 95% Confidence Interval (CI): 0.2 - 0.80, p = 0.01] among inhabitants of houses with screened doors and windows compared to those living in unscreened houses. The Protective Efficacy (PE) of screening doors and windows from clinical P. falciparum malaria was 61 % (95% CI: 18 - 83, p = 0.007). The mean indoor density of anopheline was 0.79 (95% Walad CI: 0.49, 1.25, p = 0.02) per CDC light trap per night, while it was 0 .35 (95% Walad CI: 0.22, 0.57) in unscreened houses. The screened houses had 56% fewer anopheline and 54 % fewer culicine compared to control houses. Among screened houses 97.9 % of screened windows and 63.8 % of screened doors were intact at eleven months of installation. Almost all participants of in-depth interviews were willing to continue using the screening of doors and windows. Screening of doors and windows are effective, durable and well-accepted means to control indoor malaria transmission. Hence, currently available malaria control interventions can beXII supplemented with screening doors and windows with wire-mesh for further reducing and ultimate eliminating of malaria.