Effectiveness of peridomestic space spraying with insecticide on dengue transmission; systematic review

OBJECTIVE: To review the evidence on effectiveness of peridomestic space spraying of insecticides in reducing wild Aedes populations and interrupting dengue transmission. METHODS: Comprehensive literature search of MEDLINE, EMBASE, LILACS, Web of Science, WHOLIS, MedCarib and CENTRAL, and a manual search of reference lists from identified studies. Duplicates were removed and abstracts assessed for selection. All field evaluations of peridomestic space spraying targeting wild adult Aedes vectors in dengue endemic countries were included. Data were extracted, and the methodological quality of the studies was assessed independently by two reviewers. RESULTS: Fifteen studies met the inclusion criteria. Outcome measures were heterogeneous, foregoing the possibility of meta-analysis. Thirteen studies showed reductions in immature entomological indices that were not sustained for long periods. The remainder showed space spray interventions to be ineffective at reducing adult and/or immature entomological indices. Only one study measured human disease indicators, but its outcomes could not be directly attributed to space sprays alone. CONCLUSION: Although peridomestic space spraying is commonly applied by national dengue control programmes, there are very few studies evaluating the effectiveness of this intervention. There is no clear evidence for recommending peridomestic space spraying as a single, effective control intervention. Thus, peridomestic space spraying is more likely best applied as part of an integrated vector management strategy. The effectiveness of this intervention should be measured in terms of impact on both adult and immature mosquito populations, as well as on disease transmission.