Evaluating effectiveness of screening house eaves as a potential intervention for reducing indoor vector densities and malaria prevalence in Nyabondo, western Kenya

Malaria Journal

Collins Okoyo¹  Charles Mbogo²  Peter Njoroge Ng’ang’a³  Clifford Maina Mutero⁴ 

[1] Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya;Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya;KEMRI-Wellcome Trust Research Programme, Public Health Unit, PO Box 43640 - 00100, Nairobi, Kenya;International Centre of Insect Physiology and Ecology (ICIPE), PO Box 30772, Nairobi, Kenya;Jomo Kenyatta University of Agriculture and Technology, School of Public Health, PO Box 62000, Nairobi, Kenya;International Centre of Insect Physiology and Ecology (ICIPE), PO Box 30772, Nairobi, Kenya;University of Pretoria Institute for Sustainable Malaria Control (UP ISMC, School of Health Systems and Public Health, University of Pretoria, Private Bag X363, 0001, Pretoria, South Africa;

关键词: gambiae;    Eaves;    Screening;    Malaria;    Prevalence;    Mosquitoes;    Vector control;   

DOI  :  10.1186/s12936-020-03413-3

来源: Springer

【 摘 要 】

BackgroundMosquito-proofing of houses using wire mesh screens is gaining greater recognition as a practical intervention for reducing exposure to malaria transmitting mosquitoes. Screening potentially protects all persons sleeping inside the house against transmission of mosquito-borne diseases indoors. The study assessed the effectiveness of house eaves screening in reducing indoor vector densities and malaria prevalence in Nyabondo, western Kenya.Methods160 houses were selected for the study, with half of them randomly chosen for eaves screening with fibre-glass coated wire mesh (experimental group) and the other half left without screening (control group). Randomization was carried out by use of computer-generated list in permuted blocks of ten houses and 16 village blocks, with half of them allocated treatment in a ratio of 1:1. Cross-sectional baseline entomological and parasitological data were collected before eave screening. After baseline data collection, series of sampling of indoor adult mosquitoes were conducted once a month in each village using CDC light traps. Three cross-sectional malaria parasitological surveys were conducted at three month intervals after installation of the screens. The primary outcome measures were indoor Anopheles mosquito density and malaria parasite prevalence.ResultsA total of 15,286 mosquitoes were collected over the two year period using CDC light traps in 160 houses distributed over 16 study villages (mean mosquitoes = 4.35, SD = 11.48). Of all mosquitoes collected, 2,872 (18.8%) were anophelines (2,869 Anopheles gambiae sensu lato, 1 Anopheles funestus and 2 other Anopheles spp). Overall, among An. gambiae collected, 92.6% were non-blood fed, 3.57% were blood fed and the remaining 0.47% were composed of gravid and half gravid females. More indoor adult mosquitoes were collected in the control than experimental arms of the study. Results from cross-sectional parasitological surveys showed that screened houses recorded relatively low malaria parasite prevalence rates compared to the control houses. Overall, malaria prevalence was 5.6% (95% CI: 4.2–7.5) n = 1,918, with baseline prevalence rate of 6.1% (95% CI: 3.9–9.4), n = 481 and 3rd follow-up survey prevalence of 3.6% (95% CI: 2.0–6.8) n = 494. At all the three parasitological follow-up survey points, house screening significantly reduced the malaria prevalence by 100% (p < 0.001), 63.6% (p = 0.026), and 100% (p < 0.001) in the 1st, 2nd and 3rd follow-up surveys respectively.ConclusionsThe study demonstrated that house eave screening has potential to reduce indoor vector densities and malaria prevalence in high transmission areas.

【 授权许可】

CC BY