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

Abstract

IntroductionInsecticide-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.MethodsMEDLINE, 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.ResultsTwenty-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.ConclusionThere 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.

Evidence-based vector control? Improving the quality of vector control trials

“…Based on our experience systematically reviewing the literature [16][17][18][19][20], we have identified repeated problems with vector control studies. To advance evidence-based policy making, the quality of evidence on vector control interventions -specifically the Malaria incidence House screening Socio-economic status (conf ounder)…”

Public Health Interventions for Aedes Control in the Time of Zikavirus– A Meta-Review on Effectiveness of Vector Control Strategies

“…All eight reviews [16–23] reported on the effects of chemical control on entomological indices and 4/8 [16–18, 22] on dengue incidence. Chemical control included insecticide spraying, insecticide treated curtains, nets and screens, and larvicide application (particularly temephos).…”

“…Wilson and colleagues reviewed the effect of insecticide treated nets (1 study), curtains (3 studies) and screens (1 study) on entomological indices and of insecticide treated screens on dengue seroconversion [22]. Four studies had contemporary control groups (RCTs) and one was pre-post design.…”

Use of Insecticide-Treated Nets Among Pig Owners Living in Japanese Encephalitis Endemic Areas of Northern Myanmar

“…The systematic review and meta-analysis identified clear evidence that ITNs have the potential to reduce pathogen transmission and morbidity from a vectorborne disease where vectors enter a house [12]. However, the use of ITNs is related to many factors.…”

“…There is also no established surveillance system in place [8]. Therefore, insecticide-treated bednets (ITNs) are one of the most effective methods to prevent mosquito-borne zoonotic disease including JE [10][11][12][13] in this country. Previous research studies identified several factors related to the use of ITNs: these include socio-demographic factors, availability of bed nets, knowledge, and attitudes towards mosquito-borne diseases [14][15][16][17].…”