Benefit of Insecticide-Treated Nets, Curtains and Screening on Vector Borne Diseases, Excluding Malaria: A Systematic Review and Meta-analysis

• Type of Material: Article
• Authors: Anne L. Wilson, Durham University; Ramesh C. Dhiman, National Institute of Malaria Research; Uriel Kitron, Emory University; Thomas W. Scott, National Institutes of Health; Henk van den Berg, Wageningen University; Steven W. Lindsay, Durham University
• Language: English
• Date: 2014-10-09
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: Copyright 2014 Wilson et al. 2014 Wilson et al.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pntd.0003228
• Title of Journal or Parent Work: PLoS Neglected Tropical Diseases
• ISSN: 1935-2727
• Volume: 8
• Issue: 10
• Start Page: e3228
• End Page: e3228
• Grant/Funding Information: This work was supported by a grant from The Bill & Melinda Gates Foundation (OPP1053338, SWL, ALW, RCD, UK, TWS, HvdB).
• Keywords: Kala-azar; Disease vectors; Meta-analysis; Entomology; Malaria; Infectious disease control; Insecticides; Leishmaniasis
• Research Categories: Biology, Entomology; Environmental Sciences

Abstract

Introduction: Insecticide-treated nets (ITNs) are one of the main interventions used for malaria control. However, these nets may also be effective against other vector borne diseases (VBDs). We conducted a systematic review and meta-analysis to estimate the efficacy of ITNs, insecticide-treated curtains (ITCs) and insecticide-treated house screening (ITS) against Chagas disease, cutaneous and visceral leishmaniasis, dengue, human African trypanosomiasis, Japanese encephalitis, lymphatic filariasis and onchocerciasis. Methods: MEDLINE, EMBASE, LILACS and Tropical Disease Bulletin databases were searched using intervention, vector- and disease-specific search terms. Cluster or individually randomised controlled trials, non-randomised trials with pre- and post-intervention data and rotational design studies were included. Analysis assessed the efficacy of ITNs, ITCs or ITS versus no intervention. Meta-analysis of clinical data was performed and percentage reduction in vector density calculated. Results: Twenty-one studies were identified which met the inclusion criteria. Meta-analysis of clinical data could only be performed for four cutaneous leishmaniasis studies which together showed a protective efficacy of ITNs of 77% (95%CI: 39%–91%). Studies of ITC and ITS against cutaneous leishmaniasis also reported significant reductions in disease incidence. Single studies reported a high protective efficacy of ITS against dengue and ITNs against Japanese encephalitis. No studies of Chagas disease, human African trypanosomiasis or onchocerciasis were identified. Conclusion: There are likely to be considerable collateral benefits of ITN roll out on cutaneous leishmaniasis where this disease is co-endemic with malaria. Due to the low number of studies identified, issues with reporting of entomological outcomes, and few studies reporting clinical outcomes, it is difficult to make strong conclusions on the effect of ITNs, ITCs or ITS on other VBDs and therefore further studies be conducted. Nonetheless, it is clear that insecticide-treated materials such as ITNs have the potential to reduce pathogen transmission and morbidity from VBDs where vectors enter houses.