2020年洪涝灾害后湖南省钉螺扩散情况调查

目的 开展2020年洪涝灾害后湖南省血吸虫病流行区钉螺扩散情况调查，为全省钉螺控制措施的制定提供建议。方法 采取环境抽查法和系统抽样法相结合的方式对全省41个受洪涝灾害影响的血吸虫病流行县（市、区）进行钉螺调查，通过压碎镜检法鉴定钉螺死活及血吸虫感染情况，分析钉螺扩散面积、有螺框出现率、活螺密度等螺情指标。结果 2021年钉螺调查发现，湖南省41个血吸虫病流行县（市、区）有11个县（市、区）96个环境出现钉螺扩散，扩散有螺面积1 084.09 hm²，有螺框出现率7.41%，活螺平均密度0.183 4只/0.1 m²，未发现感染性钉螺。湘江、资水、澧水和洞庭湖流域均出现螺情扩散，其中澧水流域钉螺扩散的环境数及面积最多，分别为81个、970.44 hm²（占89.52%）。扩散性质以新发环境为主，新发钉螺面积754.54 hm²（占69.60%）；扩散环境以滩地为主，扩散面积968.74 hm²（占89.36%）；植被以杂草为主，扩散面积883.76 hm²（占81.52%）。结论 2020年洪涝灾害后，湖南省血吸虫病流行区出现了较大面积的钉螺扩散，需要加大查螺灭螺、环境改造和螺情监测力度，巩固全省血吸虫病防治成果。

Investigation on the diffusion of snails after flood disaster in 2020in Hunan Province

Objective To investigate on snail spread in schistosomiasis endemic areas of Hunan Province after flood disaster in 2020 for proposals in planning the prevention and control measures throughout the province. Methods The Oncomelania snails were investigated in the schistosomiasis endemic areas affected by flood disaster in the province by environmental sampling and systematic sampling. All snail samples collected were crushed to undergo microscopic examination for determining whether they were alive or dead and status of schistosomiasis infection. In addition, the area with snail spreading, occurrence of frame with snails and density of live snails were statistically analyzed. Results Snail spread occurred in 96 environments in 11 of the 41 schistosomiasis endemic counties (cities and districts) in Hunan Province of the snail survey in 2021. The area with snail spreading, a frame with snails and density of live snails were 1 084.09 hm², 7.41%, and 0.183 4 snails/0.1m², respectively. No infected snails were found. Snail spread was seen in the basins of Xiangjiang River, Zishui River, Lishui River and Dongting Lake, and most serious in the basins along Lishui River, with a total of 81 environments that accounted for 970.44 hm² (89.52%).The diffusion nature is dominated by the newly developed environment, with the newly developed snail area of 754.54 hm² (69.60%).The diffusion environments were primarily associated with beach (968.74 hm², 89.36%), and the vegetation with snail diffusion was dominated by weeds (883.76 hm², 81.52%). Conclusion Flood disasters can increase the risk of Oncomelania snails spreading in endemic areas. In order to consolidate the achievements of schistosomiasis control in the whole province, efforts should be made to check and control snails, improve the environment and monitor the diffusion status of snails.