The effectiveness of mosquito-proof storm drains on adult mosquito and mosquito larvae abundance: protocol of the IDAlErt storm drAin randomiSed controlled trial (IDEAS) in Barcelona, Spain

Abstract Background: Climate change is creating newly habitable environments in European cities for mosquitoes of the Aedes and Culex genera, known vectors of arboviruses such as dengue and West Nile. Urban infrastructure interventions can be effective adaptation measures for future-proofing cities, although empirical evidence of their effectiveness is scarce. The Agència de Salut Pública de Barcelona (ASPB) is structurally modifying urban storm drains in 2023 in Barcelona, Spain, to prevent the accumulation of stagnant water necessary for Aedes and Culex mosquito reproduction. Methods: In partnership with ASPB, we are conducting the IDEAS randomised controlled trial (RCT) in Barcelona to investigate the effects of mosquito-proofing storm drains on the abundance of adult Aedes albopictus and Culex pipiens mosquitoes encompassing and in the vicinity of drains. Using a parallel-arm design, we have randomised 44 drains to receive mosquito-proofing modification (intervention) or not (control). The primary outcome is the combined counts of total adult Ae.albopictus and Cx.pipiens mosquitoes captured using an entomological aspirator. Secondary outcomes include the presence and total counts of mosquito larvae in water samples. We are measuring these outcomes weekly at each drain starting on 26 June 2023 until no mosquitos are detected. Results: We will quantify outcomes comparing mosquito-proofed and control drains using generalised linear mixed models. We will also conduct stratified analyses by species, sex, and sensitivity analyses, including environmental and sociodemographic factors. Conclusion: Our trial is motivated by the importance of testing urban infrastructure interventions to inform investments for future-proofing European cities against climate change-driven proliferation of infectious disease vectors. Trial registration: This trial is registered as a trial in Open Science Framework Registry. Registration DOI https://doi.org/10.17605/OSF.IO/JZQAH