The impact of large-scale deployment of mosquitoes on dengue and other -borne diseases in Rio de Janeiro and Niterói, Brazil: study protocol for a controlled interrupted time series analysis using routine disease surveillance data.

Rio de Janeiro and Niterói are neighbouring cities in southeastern Brazil which experience large dengue epidemics every 2 to 5 years, with >100,000 cases notified in epidemic years. Costs of vector control and direct and indirect costs due to the -borne diseases dengue, chikungunya and Zika were estimated to total $650 million USD in 2016, but traditional vector control strategies have not been effective in preventing mosquito-borne disease outbreaks. The method is a novel and self-sustaining approach for the biological control of -borne diseases, in which the transmission potential of mosquitoes is reduced by stably transfecting them with the bacterium ( Mel strain). This paper describes a study protocol for evaluating the effect of large-scale non-randomised releases of -infected mosquitoes on the incidence of dengue, Zika and chikungunya in the two cities of Niterói and Rio de Janeiro. This follows a lead-in period since 2014 involving intensive community engagement, regulatory and public approval, entomological surveys, and small-scale pilot releases. The releases during 2017-2019 covered a combined area of 170 km with a resident population of 1.2 million, across Niterói and Rio de Janeiro. Untreated areas with comparable historical dengue profiles and demographic characteristics have been identified as comparative control areas in each city. The proposed pragmatic epidemiological approach combines a controlled interrupted time series analysis of routinely notified suspected and laboratory-confirmed dengue and chikungunya cases, together with monitoring of -borne disease activity utilising outbreak signals routinely used in public health disease surveillance. If the current project is successful, this model for control of mosquito-borne disease through releases can be expanded nationally and regionally.