2020年洪涝灾害对长江芜湖段钉螺分布的影响

目的 分析2020年洪涝灾害对芜湖市钉螺分布的影响,为制定芜湖市“十四五”血防规划和精准防控措施提供科学依据。方法 采取系统抽样结合环境抽查的方法,调查芜湖市历史有螺环境、现有螺环境和可疑钉螺环境钉螺分布情况,对捡获的钉螺压碎镜检,了解钉螺死活及血吸虫感染情况,统计活螺密度等指标。结果 芜湖市历史有螺面积为14 475.24 hm²,现有钉螺境面积为4 588.72 hm²,其中湖沼型及山丘型有螺面积分别为4 210.32 hm²和 378.40 hm²。全市平均活螺框出现率为14.59%,平均活螺密度为 0.50只/0.1 m²。全市钉螺孳生环境 2 745处（块）,其中湖沼型和山丘型分别为491处（块）和2 254处（块）,分别占17.89%和82.11%。现有钉螺面积主要分布于滩地和沟渠环境,分别占现有钉螺面积的92.51%和6.29%,还有部分钉螺分布于塘堰、水田等环境。在全部历史有螺环境中,以Ⅱ类、Ⅲ类环境（目前仍具备钉螺孳生基本条件）居多,共1 739处（块）（占63.35%）。全市未发现血吸虫感染性钉螺,新发现和复现钉螺面积268.21 hm²。结论 芜湖市钉螺分布点多面广,钉螺多分布于滩地,易受洪涝灾害的影响,本次调查在3个县（市、区）的30处（块）滩地环境出现钉螺扩散。要加强灾后螺情监测,并将Ⅱ类、Ⅲ类环境作为螺情监测的重点区域,及早发现、识别和评估血吸虫病传播风险,降低洪涝灾害对血吸虫病防治进程的影响,促进血吸虫病消除进程。

Influence of flood disaster on Oncomelania snail distribution in Wuhu section of Yangtze River in 2020

Objective To analyze the impact of the flood disaster on the distribution of Oncomelania snails in 2020 in Wuhu City, to provide scientific basis for formulating the "14th Five-Year Plan" for schistosomiasis control and precise prevention and control measures in Wuhu City. Methods Systematic sampling combined with environmental spot check was used to investigate the distribution of snails in the historical snail's environment, existing snail's environment and suspected snail's environment in Wuhu City. The collected snails were crushed and examined by microscope to understand the death and life of snails and the infection of Schistosoma japonicum, and the density of live snails and other indicators were counted. Results The historical area of snails was 14 475.24 hm² in Wuhu City, and the existing area of snails was 4 588.72 hm², including 4 210.32 hm² for lake type and 378.40 hm² for hill type snails. The average occurrence rate of live snails was 14.59%, and the average density of live snails was 0.50 snails/0.1 m² in Wuhu City. There were 2 745 snail breeding environments, of which 491 were lake type and 2 254 are hill type, accounting for 17.89% and 82.11% respectively. The existing snail area was mainly distributed in the beaches and ditches, accounting for 92.51% and 6.29% of the existing snail area respectively. Some snails were distributed in ponds, paddy fields and other environments. Among all the historical snail habitats, the majority were class Ⅱ and class Ⅲ environments (which still have the basic conditions for snail breeding at present), with a total of 1 739 sites (blocks), accounting for 63.35% of the total environment. No schistosomiasis infected snails have been found, and the newly discovered and recovered snails cover an area of 268.21 hm² in Wuhu City. Conclusions The distribution of snails is extensive in Wuhu City, and snails are mostly distributed in beaches, which are vulnerable to the impact of flood disasters. The spread of Oncomelania snails is found in 30 marshlands in 3 counties in this survey. It is necessary to continue to strengthen snail monitoring after disasters, and take class Ⅱ and class Ⅲ environments as key areas for snail monitoring, so as to find, identify and evaluate the risk of schistosomiasis transmission as soon as possible, to avoid or reduce the impact of flood disasters on the process of schistosomiasis control, and promote the process of schistosomiasis elimination.