Construction and application of the surveillance system for schistosomiasis transmission risk in Sichuan Province

: [摘要] 目的 构建四川省血吸虫病传播风险监测体系, 为推进全省消除血吸虫病进程提供技术保障。方法 在四川 省11个市 (州) 63个血吸虫病流行县 (市、区) 设立血吸虫病传播风险监测区, 开展野粪、发热病人、家畜和野生动物血吸 虫感染监测, 重点环境疫水和螺情监测, 以及钉螺输入扩散、漂浮物携带钉螺、生态湿地钉螺孳生风险监测。结果 2015–2018 年, 四川省共检测野粪 1 636 份, 发现血吸虫阳性野粪3份, 阳性率为0.18%; 监测各类家畜 3 995 头 (只) 、野鼠59 只, 未发现血吸虫感染动物。2018年共监测发热病人49 414人, 发现血清学检测阳性493人; 其中445人进行了粪检, 未 查出粪检阳性病人。2010–2018 年, 共设立哨鼠疫水监测点 93个, 投放哨鼠3 994只, 发现血吸虫感染阳性哨鼠1只。2015–2018年, 共调查重点环境4 156处、1 998.46 hm2, 查出有螺环境668 处 (占16.07%)、有螺面积 193.26 hm2; 2017–2018 年监测有植物引种的钉螺输入可疑环境497处, 发现有螺环境65处、钉螺2 673只; 2017–2018年设立打捞漂浮物监测点 593个, 打捞漂浮物共9 191.39 kg, 检获携带钉螺186只; 2013–2015年对4个湿地环境进行风险监测, 发现2个湿地有钉 螺孳生。各环境监测查获的钉螺经检测均未发现血吸虫感染。结论 四川省已成功构建敏感有效的血吸虫病传播风险 监测体系, 但局部地区仍然存在血吸虫病传播风险。今后应继续落实以传染源控制为主的血吸虫病综合防治措施, 加强钉螺监测与控制, 强化湿地生态区的血吸虫病传播风险监测与防控。. METHODS: The surveillance sites for schistosomiasis transmission risk were assigned in 63 endemic counties (districts) of 11 cities (prefectures) in Sichuan Province. During the period from 2015 through 2018, wild feces contamination, the sources of Schistosoma japonicum infections (fever patients, livestock and wild animals), water infectivity in key settings, snail distribution in key settings, and snail breeding risk (snail importation and spread, floating debris carrying snails and snail breeding in ecological wetlands) were monitored in the surveillance sites. RESULTS: From 2015 to 2018, a total of 1 636 wild faces were detected in Sichuan Province, and 3 faces were positive for S. japonicum, with a 0.18% positive rate; among 3 995 livestock and 59 wild mice monitored, no S. japonicum infection was detected. A total of 49 414 fever patients were monitored in 2018, and 493 were seropositive for S. japonicum infection; then, 445 seropositives were subjected to stool examinations, and no egg-positives were found. From 2010 to 2018, a total of 93 sentinel sites were assigned, and 3 994 sentinel mice were placed for monitoring the water infectivity, with one S. japonicum-infected mouse detected. Between 2015 and 2018, a total of 4 156 key settings were investigated covering an area of 1 998.46 hm2, and 668 settings were detected with snails (16.07%), covering an area of 193.26 hm2; 497 suspected settings with a likelihood of snail importation with plant introduction were monitored from 2017 to 2018, and 65 settings with snails were found with 2 673 snails captured; 593 sites were assigned to collect the floating debris from 2017 to 2018, and 9 191.39 kg floating debris were collected with 186 snails captured; 4 wetlands were monitored for the risk of schistosomiasis transmission from 2013 to 2015, and snail breeding was found in 2 wetlands. No S. japonicum infection was identified in snails captured from all surveillance sites. CONCLUSIONS: A sensitive and effective schistosomiasis transmission risk surveillance system has been successfully established in Sichuan Province. There is still a risk of schistosomiasis transmission risk in local areas of Sichuan Province. Therefore, the integrated schistosomiasis control measures with emphasis on the control of the source of S. japonicum infections should be further intensified, and snail monitoring and control and monitoring and control of schistosomiasis in wetlands should be also intensified.