Epidemic surveillance of schistosomiasis after blocking its transmission in Jiaxing

objective The study was designed to analyze the results of epidemic surveillance on schis- tosomiasis from 1995 to 2005 in Jiaxing after its epidemic transmission was blocked and to find out the potential epidemic tendency of schistosomiasis in the region for providing scientific evidence for the surveillance on schistosomiasis.Methods Surveillance data on schistosomiasis from 1995 to 2005 in Jiaxing were collected and statistically analyzed.Results An accumulative area of 115 695 590 m~2 was examined for oncomelania in the 11 years.143 snail sites with an area of 497 590 m~2 were reexamined in 5 counties/cities for 10 consecutive years beginning from 1996,and 45 735 alive snails were dis- sected under microscope with no infected snails found.Seroimmunologic tests were conducted for a total of 752 211 patients in the 11 years.There were 18 034 positive patients found,of whom 9485 cases had negative stool tests.Seroimmunologic tests were done for 6921 suspected cases and positive results found in 1189 cases,for whom stool tests were done and 3 of them including 2 acute and 1 chronic schistosomiasis cases were positive.The 3 cases were all of floating population from outside epidemic ar- eas.Conclusion The achievements of schistosomiasis control and prevention has been consolidated. However,the mildly rebounding snail situation and the existing input infection sources indicate a risk of local prevalence.Thus,the surveillance on snail situation and floating population from outside epidemic areas should be emphasized.