Authors

Discussion

Schistosomiasis control programmes map the distribution of infection prior to commencing treatment. This enables each district, or so-called ‘implementation unit’, to be categorised according to World Health Organization (WHO) prevalence thresholds which in turn determine the appropriate treatment strategy (by mass drug administration, MDA) to control schistosomiasis-related morbidity. With the vision of “a world free of schistosomiasis”, the WHO and its partners have pledged to meet the ambitious goals of controlling morbidity of schistosomiasis (<5% heavy infection prevalence) by 2020 and achieving elimination as a public health problem (<1% heavy infection prevalence) and interruption of transmission in selected regions by 2025. The guidelines for progressing through these stages are predominantly based on expert opinion. This study aims to redress this by providing empirical evidence to assist programmes in achieving the 2020 and 2025 goals by answering two key questions: 1) how long will it takes countries to reach the WHO 2020/2025 targets, and 2) how should countries best use sentinel site monitoring and evaluation data? Our analysis of the large datasets available at the Schistosomiasis Control Initiative demonstrate that countries transition from controlling morbidity to eliminating schistosomiasis as a public health problem at different rates depending on the predominant schistosome species and baseline endemicity. These results provide the first empirical comparison with WHO threshold criteria on morbidity control and elimination and question whether a one-size-fits-all approach is optimal for guiding schistosomiasis treatment strategies.