2020 年云南省血吸虫病传播风险评估结果分析

目的 评估云南省 2020 年的血吸虫病传播风险,为制定防治方案和措施提供依据。 方法 选取云南省巍山、弥渡、大理、宁蒗 4 个县(市)作为风险评估对象,每县(市)选择 2 个流行乡镇,每个乡镇选取 1 个行政村开展评估工作。 整理分析 2018—2020 年评估村的血吸虫病疫情和防治资料;2020 年对评估村进行现场螺情和野粪调查,综合评估血吸虫病传播风险。 结果 疫情资料显示,7 个被评估村 2018—2020 年均未查到病人、病畜和感染性钉螺。 现场钉螺调查结果显示,历史有螺环境系统抽样捕获活螺 10 只,有螺框出现率为 6. 52%(3 / 46),活螺平均密度为 0. 22 只 / 0. 11 m2;环境抽查 3 248 框,捕获活螺 2 只。 现有螺环境系统抽样捕获活螺 1 082 只,有螺框出现率为 4. 01%(297 / 7 413),活螺平均密度为 0. 15 只 / 0. 11 m2;环境抽查 2 627 框,捕获活螺 31 只。 捡获的活螺进行 LAMP 检测,结果均为阴性。 共捡获野粪 261 份,其中牛粪 54 份(20. 69%)、狗粪 129 份(49. 43%)、马属动物(驴、骡)粪 33 份(12. 64%)、猪粪 7 份(2. 68%)、羊粪 21 份(8. 05%)、人粪 17 份(6. 51%),经顶管孵化法均未检出阳性。被评估县风险等级为Ⅲ级。 结论 当前云南省血吸虫病传播处于低风险状态,但家畜存栏数量大、家畜散放、野粪种类和数量较多、历史有螺环境钉螺复现等情况依然存在,提示今后需继续加强实施综合防治措施,建立完善的风险评估及监测机制,巩固防治成果。

Analysis of the risk assessment result of schistosomiasis transmission in Yunnan Province in 2020

Objective To evaluate the transmission risk of schistosomiasis in Yunnan Province in 2020 for evidence to formulate prevention and control measures against this infection. Methods Four counties (cities),including Weishan,Midu, Dali and Ninglang of Yunnan Province,were included to undergo risk assessment in 2020. The evaluation was performed in one administrative village selected from each township. The data on schistosomiasis prevalence and control were obtained from 2018 to 2020 in the counties involved in assessment. Field survey was conducted on the snail prevalence and infection in the wild feces in sampled villages. Then the results were comprehensively evaluated for the risks of schistosomiasis transmission. Results The epidemiological data showed that no patients,infected animals or infected snails were detected in the 7 villages assessed between 2018 and 2020. In the field survey site,only 10 living snails were captured by systematic sampling in areas with snail prevalence in history. The occurrence rate of snail was 6. 52% (3 / 46) for individual frame,and the average density of living snails was 0. 22 snails / 0. 11 m2,2 living snails were captured in 3 248 frames by environmental sampling. Totally,1 082 living snails were captured by systematic sampling in the environment with snails. The total occurrence rate of frames with living snails was 4. 01%(297 / 7 413),and the average snail density was 0. 15 / 0. 11 m2,31 living snails were captured in 2 627 frames by environmental sampling. LAMP detection showed negative results in all snails obtained. No positive infection was detected by miracidium hatching test in a total of 261 aliquots of wild feces,including 54 aliquots of cow feces (20. 69%),129 dog feces (49. 43%),33 equine feces ( donkey and mule) (12. 64%),7 pig feces (2. 68%),21 sheep feces (8. 05%) and 17 human feces (6. 51%). The risk level of each assessment county is level Ⅲ. Conclusion The risk of schistosomiasis transmission was concluded at lower level in Yunnan Province in current study,yet certain unfavorable aspects still exist,including large number of livestock in stock,free ranged livestock,complex and large quantity of wild feces as well as reemergence of Oncomelania hupensisin historical snail environment. These findings suggest that it is essential to further strengthen the prevention and control measures and develop perfect risk assessment and monitoring mechanisms in order to consolidate the previous efforts.