Modeling the dynamics and control of Schistosoma japonicum transmission on Bohol island, the Philippines.

We have investigated a mathematical model for the transmission of Schistosoma japonicum in the infested region of northeastern Bohol island in the Philippines. The development of transmission models is important for planning control strategies. Since S. japonicum has a complicated mode of transmission, the rates of transmission among its hosts cannot be measured directly by field observation. Instead, they have been estimated through model analysis. The model takes into account the seasonal variations and includes a function of control measures. In 1981, a project to eliminate schistosomiasis started on Bohol island. The prevalence decreased dramatically and has kept low level less than 1%. The simulations based on the model predicted that there is little probability of resurgence of an epidemic in the northeastern endemic villages of Bohol island due to the fact that the project has attained a high coverage of selective mass treatment based on stool examination accompanied by a successful snail control operation.