When decisions to intervene in different schistosomiasis severity states are taken in isolation, inefficiencies are unavoidable due to failure to take account of the synergy between community and facility level options. To date no studies have been conducted of the sequential nature of decision-making processes in schistosomiasis. The main aim of this study is to develop a methodology that could be used to compute the costs and health benefits of alternative strategies for ameliorating the burden of illness from schistosomiasis, with a view to determine that strategy which would produce the greatest excess of benefits over cost. In other words, the goal is to develop a conceptual framework that could be used to map out the most efficient path of options for intervention across a spectrum of schistosomiasis states - asymptomatic, mild, moderate, severe, and very severe.

A cost-utility decision analysis (CUDA) model was developed and applied to the population living within the schistosomiasis endemic region of Kenya covered by the Mwea Irrigation Scheme. Both primary and secondary level options were included in the analysis.

The main findings are as follows. Strategies involving treatment at the community level were generally superior to non-treatment community strategies. The selective population praziquantel chemotherapy (SPCPS) was found to be the optimal strategy. Mollusciciding strategies are the most cost-effective among the non-treatment strategies. The results of the sensitivity analyses were, however, mixed. The inconclusive nature of the results indicates that firm policy conclusions cannot be made on the basis of current epidemiological information, and more research is urgently required to establish both the validity and reliability of the health-related quality of life (HRQoL), and the Delphi technique (DT) measurements used in the study.