四川省湿地血吸虫病流行因素监测

目的　调查四川省湿地血吸虫病流行因素，为湿地血吸虫病防控提供科学依据。方法　选取四川省人工和自然湿地，收集相关资料，开展常规钉螺调查、人群血吸虫病病情调查、钉螺漂浮扩散试验、问卷调查、疫水测定和回顾性调查等。结果　2015年四川省梅湾水库湿地上、下游活螺平均密度分别为0.003只/0.1 m2和2.033只/0.1 m2，广汉金雁湖活螺密度为0.08只/0.1 m2，广汉马牧河活螺密度为0.21只/0.1㎡，西昌邛海湿地公园建设前活螺密度为0.02只/0.1 m2。人工模拟钉螺漂浮扩散试验显示，钉螺最远漂移距离为2 000 m；8.80%（41/466）的湿地人群有接触疫水行为。投放哨鼠690只，解剖677只，未发现血吸虫感染阳性哨鼠。回顾性调查发现，丹棱梅湾水库建设造成血吸虫病疫情扩散；广汉金雁湖建成5年后出现钉螺，入湖沟渠发现血吸虫感染性钉螺。结论　四川省部分湿地有钉螺分布，对于自然形成湿地应以保护湿地、生态环境灭螺为主，防止钉螺输入；对于人工修建湿地，存在随水系漂浮输入钉螺的可能性，建议工程建设时彻底灭螺。两类湿地都要开展长期系统血吸虫病监测。

Surveillance of epidemic factors of schistosomiasis in wetlands in Sichuan Province

Objective　To investigate the epidemic factors of schistosomiasis in wetlands in Sichuan Province, so as to provide scientific evidence for the prevention and control of schistosomiasis in wetlands. Methods　The artificial and natural wetlands were selected from Sichuan Province, and the relevant data regarding wetlands were collected. Routine snail survey, investigation on human morbidity due to schistosomiasis, snail diffusion experiments, questionnaire survey, determination of water infectivity and retrospective survey were conducted. Results　In Sichuan Province, the mean densities of living snails were 0.003 snails/0.1 m2 and 2.033 snails/0.1 m2 in the upper and lower reaches of the Meiwan Reservoir wetlands, 0.08 snails/0.1 m2 in the Jinyan Lake of Guanghan City, 0.21 snails/0.1 m2 in Muhe River of Guanghan City, and 0.02 snails/0.1 m2 prior to the construction of Qionghai wetland park in Xichang City in 2015. Artificial simulation experiments showed that the largest distance of snail diffusion in water was 2 000 m. There were 8.80% (41/466) of subjects that lived neighboring wetlands, worked in wetlands and visited wetlands having infested water contact behaviors. A total of 690 sentinel mice were assigned, and no Schistosoma japonicum infection was detected in the 677 mice dissected. Retrospective survey showed that the construction of the Meiwan Reservoir caused the spread of schistosomiasis in Dailing County, and snails were found in the ditches entering the Jinyan Lake and in Jinyan Lake areas 5 years following the construction of the Jinyan Lake in Guanghan City, with S. japonicum?infected snails detected in the ditches entering the Jinyan Lake. Conclusions　O. hupensis snails are found in some wetlands in Sichuan Province. Protection of wetlands and snail control with environmental improvements are recommended for the prevention of snail importation in natural wetlands, while in artificial wetlands, thorough snail control is recommended during the construction of the wetlands because of the likelihood of snail importation via water systems. In addition, both natural and artificial wetlands require long?term systematic surveillance of schistosomiasis.