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

Background: There is renewed interest in effective measures to control Zika and dengue vectors. A synthesis of published literature with a focus on the quality of evidence is warranted to determine the effectiveness of vector control strategies. Methodology: We conducted a meta-review assessing the effectiveness of any Aedes control measure. We searched Scopus and Medline for relevant reviews through to May 2016. Titles, abstracts and full texts were assessed independently for inclusion by two authors. Data extraction was performed in duplicate and validity of the evidence was assessed using GRADE criteria. Findings: 13 systematic reviews that investigated the effect of control measures on entomological parameters or disease incidence were included. Biological controls seem to achieve better reduction of entomological indices than chemical controls, while educational campaigns can reduce breeding habitats. Integrated vector control strategies may not always increase effectiveness. The efficacy of any control programme is dependent on local settings, intervention type, resources and study duration, which may partly explain the varying degree of success between studies. Nevertheless, the quality of evidence was mostly low to very low due to poor reporting of study design, observational methodologies, heterogeneity, and indirect outcomes, thus hindering an evidence-based recommendation. Conclusions: The evidence for the effectiveness of Aedes control measures is mixed. Chemical control, which is commonly used, does not appear to be associated with sustainable reductions of mosquito populations over time. Indeed, by contributing to a false sense of security, chemical control may reduce the effectiveness of educational interventions aimed at encouraging local people to remove mosquito breeding sites. Better quality studies of the impact of vector control interventions on the incidence of human infections with Dengue or Zika are still needed. Author Summary: Various strategies for the control of mosquito-borne diseases exist and have been used for decades. The effectiveness of these control measures has been evaluated in several systematic reviews, however, their conclusions were contradicting. The current Zika outbreak in the Americas renewed the global health community’s interest in the control of Aedes transmitted diseases (dengue, yellow fever and chikungunya). We sought to provide an up to date systematic review about the effectiveness of chemical, biological, educational and integrated vector control strategies. In addition, we looked at recent primary studies that were not included in any systematic review as well as novel tools for mosquito control. This meta-review provides a comprehensive list of systematic reviews on the effect of vector control interventions on entomological parameters (most often indicators of vector density) or disease incidence. Biological control was found to achieve higher reduction of mosquito populations than chemical control. Educational campaigns are essential to reduce breeding sites and interrupt disease transmission. Integrated vector control strategies may not always increase effectiveness. The quality of the evidence was low to very low for most interventions. The effectiveness of any control strategy is setting- dependent.