[Study on the re-emerging situation of schistosomiasis epidemics in areas already under control and interruption]

To study the current situation and the cause of schistosomiasis resurgence in order to provide reference for formulation of control strategy.

Data in 1999 - 2003 and baseline data in some areas were collected and analyzed retrospectively.

Resurgence was seen in 6.15% (16/260) of the areas and one farm where transmission of schistosomiasis had been interrupted and 33.33% (21/64) of the areas already under control. Snails appeared to have been rebounded only in six counties (farm) while in thirty two counties that rebound was seen in both snails and disease prevalence. Tendency of increase in the total numbers of patients, acute patients and cattle with schistosomiasis, areas with snails were seen from 1999 to 2003.

Environmental, ecological, societal factors such as flood, acequia, lack of expenditure and lack of incentives at work etc. contributed to the resurgence of epidemics in those areas that criteria had been reached. Surveillance and supervision on the sources of infection and snail diffusion, especially in the areas where the transmission of schistosomiasis had already been under control.