Schistosomiasis - assessing progress towards the 2020 and 2025 global goals

BACKGROUND: With the vision of "a world free of schistosomiasis", the World Health Organization (WHO) has set ambitious goals, by 2020 and 2025, for, respectively, the control and elimination as a public health problem (EPHP) of this debilitating disease. As these milestones become imminent and if programmes are to succeed, it is crucial to gather quantitative evidence to support the existing universal approach of WHO programmatic guidelines. METHODS: Multi-year cross-sectional data were collated and analysed from nine national schistosomiasis control programmes – eight in sub-Saharan Africa, and Yemen. Data were analysed by Schistosoma species (Schistosoma mansoni, S. haematobium), number of treatment rounds, overall prevalence and prevalence of heavy-intensity infection. RESULTS: All but one country programme achieved control of morbidity targets for both schistosome species considerably sooner than current WHO guidelines project. Programmes with low baseline endemicity levels were more likely to reach control and EPHP targets. Intra-country variation was seen in the relationship between overall prevalence and that of heavy-intensity infection, and between treatment rounds, highlighting the challenges of using one metric to define control in all epidemiological settings. CONCLUSIONS: If countries follow the current guidelines, many programmes would need to continue beyond 2020. Our results suggest the need of a reduced timeframe from baseline to the next programmatic decision point (i.e. <5 years, rather than the proposed 5-10 years). This has important implications for national programmes, determining impact and resource allocations as well as indicating when to re-assess to determine the next treatment strategy.