Discussion

The design of control programmes for schistosomiasis are based upon reproducible epidemiological patterns, in which children carry the major burden of infection, regardless of level of exposure to the parasite, with development of partial immunity being apparent in older adolescents and adults. The rate at which this immunity develops within populations is proposed to increase with force of transmission. The current models of schistosome infection dynamics on which the long-term success of control programmes is predicted, often lack relevant immunity parameters, highlighting the continuing need for good quality immuno-epidemiological data. The targets of anti-schistosome immunity, and how these relate to the slow development of immunity will be discussed in the context of force of transmission, along with the potential implications for control programme success.