Towards a Framework for the Successful Implementation of Wastewater and Environmental Surveillance for Diarrhoeal Diseases in Sub-Saharan Africa

Wastewater and environmental surveillance (WES) provides a complementary approach to traditional clinical surveillance, particularly in low- and middle-income countries (LMICs) where clinical coverage is variable. WES implementation across these settings can generate comparable, reliable data to inform regional and global public-health action. We implemented a WES study in Burkina Faso, the Democratic Republic of the Congo (DRC), and Tanzania, across diverse sanitation systems. Wastewater and surface water samples were collected and analysed using culture-based methods to detect and isolate faecal indicator bacteria (FIBs), toxigenic Vibrio cholerae, and Salmonella Typhi, following shared protocols where possible. Contextual information, including available clinical surveillance data and site descriptions, was incorporated to support data interpretation. Across the three countries, a total of 112 samples of wastewater and surface water were analysed during monthly sampling campaigns from January to September 2025. The presence of faecal contamination was confirmed at 12 sampling sites across the three countries, with FIB detected at least once at each site. Presumptive S. Typhi was detected at three sites in Burkina Faso and one site in Tanzania, while V. cholerae was detected at one site in Tanzania; neither pathogen was detected at any sites in the DRC. Clinical data from Burkina Faso indicated typhoid fever cases in all corresponding catchment areas, while cholera cases were absent. In the DRC, clinical data indicated the presence of both typhoid fever and cholera cases in the vicinity of all sampling locations. Implementation challenges included laboratory capacity gaps, supply-chain delays, and incomplete adherence to harmonised protocols. Lessons learned on laboratory implementation, sampling strategies, and data management were systematically documented, and active stakeholder participation facilitated site selection, interpretation, and integration of findings. Coordinated WES can complement clinical surveillance, and the study provides a further exploration of its potential role in diarrhoeal disease surveillance to support public health action in sub-Saharan Africa.