Surveillance for schistosomiasis 20 years after blocking its spread in Tongxiang, Zhejiang

Objective To understand the schistosomiasis situation in Tongxiang 20 years after its spread was blocked and provide evidence to keep the gain of schistosomiasis control. Methods Descriptive epidemiological analysis was conducted on the surveillance data of schistosomiasis in Tongxiang from 1994 to 2003. Results One imported acute schistosomiasis case and 1 chronic schistosomiasis case were etiological confirmed. Only 1 snail belt was found in a village in 2003 with an area of 7164 m2 and snail density of 0.056/0.11 m2, no positive snails were found. Totally 207 523 residents received serological detection, in which 4173 were antibody positive (2.01%). From 1994 to 2003, a total of 147 462 residents received serological detection, in which 3850 were antibody positive (2.61%). From 2004 to 2013, a total of 60 061 residents received serological detection, in which 323 were antibody positive (0.54%). The difference in antibody positive rate between two periods had statistical significance (2=2350.93, P0.001). Conclusion Schistosomiasis is under control in Tongxiang. No indigenous case was detected, but imported case was reported. It is necessary to strengthen the surveillance for schistosomiasis in people from endemic areas to keep the gain of schistosomiasis control in Tongxiang.