Environmental methods for dengue vector control - A systematic review and meta-analysis

Abstract

Background: Vector control remains the primary method to prevent dengue infections. Environmental interventions represent sustainable and safe methods as there are limited risks of environmental contamination and toxicity. The objective of this study is to perform a systematic review and meta-analysis of the effectiveness of the following environmental methods for dengue vector control.

Methodology/principal findings: Following the PRISMA guidelines, a systematic literature search was conducted using the databases PubMed, EMBASE, LILACS, the Cochrane Library and Google Scholar. Quality assessment was done using the CONSORT 2010 checklist. For the meta-analysis the difference-in-differences (DID) and the difference-of-endlines (DOE) were calculated according to the Schmidt-Hunter method for the Breteau index (BI) and the pupae per person index (PPI). Nineteen studies were eligible for the systematic review, sixteen contributed data to the meta-analysis. The following methods were evaluated: (a) container covers with and without insecticides, (b) waste management and clean-up campaigns, and (c) elimination of breeding sites by rendering potential mosquito breeding sites unusable or by eliminating them. Study quality was highest for container covers with insecticides, followed by waste management without direct garbage collection and elimination of breeding places. Both, systematic review and meta-analysis, showed a weak effect of the interventions on larval populations, with no obvious differences between the results of each individual method. For the meta-analysis, both, container covers without insecticides (BI: DID -7.9, DOE -5) and waste management with direct garbage collection (BI: DID -8.83, DOE -6.2) achieved the strongest reductions for the BI, whereas for the PPI results were almost opposite, with container covers with insecticides (PPI: DID -0.83, DOE 0.09) and elimination of breeding places (PPI: DID -0.95, DOE -0.83) showing the strongest effects.

Conclusions: Each of the investigated environmental methods showed some effectiveness in reducing larval and pupal densities of Aedes sp. mosquitoes. However, there is a need for more comparable high-quality studies at an adequate standard to strengthen this evidence.

Fig 1. Flow diagramme.

Diagramme describing the paper selection process based on the PRISMA flow diagramme.

Fig 2

A1: Forest Plot of container covers without insecticides for the outcome Breteau Index. A2: Forest Plot of container covers without insecticides for the outcome Pupae per Person Index. B1: Forest Plot of container covers with insecticides for the outcome Breteau Index. B2: Forest Plot of container covers with insecticides for the outcome Pupae per Person Index. Fig 2C1: Forest Plot of waste management with direct garbage collection for the outcome Breteau Index. C2: Forest Plot of waste management with direct garbage collection for the outcome Pupae per Person Index. D1: Forest Plot of waste management without direct garbage collection for the outcome Breteau Index. D2: Forest Plot of waste management without direct garbage collection for the outcome Pupae per Person Index. E1: Forest Plot of elimination of breeding places for the outcome Breteau Index. E2: Forest Plot of elimination of breeding places for the outcome Pupae per Person Index. For each category, the difference-in-differences and the difference-of-endlines are presented. *Result was not included in summary measurement. **Result differs from publication. ***Method was implemented in a subsample as a second additional intervention.