Improving fitness to face arboviral outbreaks in West Africa: development of community-led approaches for vector surveillance, control and risk prediction in Ouagadougou, Burkina Faso.

The mosquito Aedes aegypti holds significant global importance as the primary vector of arboviruses. Unfortunately, there are currently no vaccines or medications accessible for preventing the transmission or treating individuals infected with the viruses it transmits (dengue, chikungunya, and Zika), and vector control remains the most effective tool to protect humans. In this project we propose to develop a community-based approach for arbovirus outbreak prevention and response in Ouagadougou. An extensive plan focussing on the abundance and distribution of Ae. aegypti in different landscapes, the genetics and behaviour of its populations, the human exposure to mosquito bites, and the arboviral circulation, will be employed to model the interplay of forces governing arboviral dynamics (dengue) and develop an improved index for estimation of arbovirus transmission risk (WP1). Some areas of Burkina Faso are difficult to access, a common situation in many countries in sub-Saharan Africa. This, combined with limited resources, confines the traditional mosquito surveillance activities to small areas of the main cities, preventing any targeted mosquito control intervention in most of the country. To try to overcome this, we will include both sampling of different representative ecologies (urban, peri-urban and rural) for established surveillance methods, and also involve citizens to use a mobile app designed for digital surveillance of mosquitoes (WP2), already in use in several areas worldwide. The feasibility, effectiveness, and benefits of digital surveillance will be assessed using WP1 entomological collection results as a comparison. A large-scale cluster randomised control trial on community-based larval source management, and smaller-scale assessments of new methodologies for the control of Ae, aegypti adults in sub-Saharan Africa are proposed (WP3). Trialling of targeted indoor residual spraying, attractive toxic sugar baits, and passive emanators of volatile pyrethroids will lead to a household-randomised trial investigation of one of these adult control tools. Control methodologies will be informed by simultaneous research on the atypical nature and variability in African Ae. aegypti bionomics and how this can be predicted by development and implementation of novel genetic tools to link risk to subspecies hybridisation from WP1. Throughout, to optimise plans for integrated control, impacts of tools with cross-efficacy between Ae. aegypti and malaria mosquitoes, both existing and invasive, will be considered and explored. Capacity building is embedded throughout, with the aim of developing skills in trial design and analysis, social science, community-based programme development and implementation, genetic diagnostics and genomics, serosurveillance, entomology and statistics/modelling (7 PhD students based in Burkina Faso). Community engagement and involvement (CEI) activities (WP5) will play a crucial role throughout the project activities and have a dedicated work package supported by researchers based both in Burkina Faso and in northern partner institutes. We believe that new evidence on arbovirus epidemiology in sub-Saharan Africa and a new generation of local specialists is urgently needed to fill the skills gaps from the bottom upwards and to equip African health systems with the experience, knowledge, and motivation to respond effectively to ABV outbreaks, particularly in the ever-increasing densely populated urban areas.