Dynamic aspects of morbidity and acquired immunity in schistosomiasis control

In schistosomiasis control, rational planning of chemotherapy programmes is complicated by the dynamic interactions between treatment and levels of acquired immunity and morbidity in the community. In this paper, mathematical models that address the development of acquired immunity and the prevalence of morbidity are incorporated within an age-structured transmission framework to explore some of the dynamic complexities of long-term chemotherapy programmes. As well as illustrating some of the potential problems inherent in predicting the consequences of control measures, the model provides insights into the dynamics of schistosomiasis transmission and the parameters that need to be measured to further improve the design of community-based control programmes.