Retrospective investigation for endemic situation of schistosomiasis in Zhejiang Province

OBJECTIVE: To analyze the changing rules of schistosomiasis endemic situation before and after reaching the criteria of schistosomiasis transmission controlled or transmission interrupted in Zhejiang Province, so as to provide scientific evidence for schistosomiasis control. METHODS: Xiuzhou District and Zhuji City were selected and investigated retrospectively to collect schistosomiasis epidemiological information 10 years before they reached the criteria of transmission controlled and the subsequent years until 2008. The database of retrospective investigation was established for analyzing the trends and rules of changes of Oncomelania hupensis snail status and schistosome infection status of cattle and human. RESULTS: The snail status and schistosome infection kept a steady declining before reaching the criteria of transmission controlled, and there were positive correlations between the area of living snails and the infection rates of human and animal in two places (r(human) = 0.764, P < 0.01, r(catlle) = 0.709, P < 0.01; r(huma) = 0.775, P < 0.01, r(catlle) = 0.676, P < 0.01); No local infection person and animal except residual snails, and found 7 cases of imported infection source were found after reaching the transmission interruption. CONCLUSION: The epidemic status of schistosomiasis in zhejiang is stable after reaching the criteria of transmission interruption, and residual snail are easy to re-found and spread under some certain conditions, and some imported cases were found sometimes, which may increase the risks for re-emergence of schistosomiasis. The integrated solidification strategy with emphasis on control of residual snails and imported cases should be taken in the areas of transmission interruption in the future.