Lv Shang-Biao, He Ting-Ting, Hu Fei, Li Yi-Feng, Yuan Min, Xie Jing-Zi, Li Zong-Guang, Li Shi-Zhu, Lin Dan-Dan
Jiangxi Provincial Institute of Parasitic Diseases, Nanchang 330096, China.
National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China.
Trop Med Infect Dis. 2023 Apr 30;8(5):259. doi: 10.3390/tropicalmed8050259.
Flooding is the main natural factor in snail diffusion, and it has a negative impact on schistosomiasis transmission. There are few studies on the spread and migration of snails following a flood; therefore, we aimed to investigate the influence of flooding on snail diffusion and explore the characteristics and laws of snail diffusion in Jiangxi Province. By using a retrospective survey and cross-sectional survey, the data on snail spreading in Jiangxi Province from 2017 to 2021 were collected. The distribution, nature, and area of snail spread were systematically analyzed in combination with the hydrological situation, types of region, and types of flood. From 2017 to 2021, a total of 120 snail-spread environments were found, including in 92 hilly areas and in 28 lake areas. The areas caused by flood and by other means numbered 6 and 114, respectively. The proportions of recurrence, expansion, and first-time occurrences were 43.42%, 38.16%, and 18.42%, respectively, and the 14 new snail environments were only distributed in the hilly areas. With the exception of 2018, the ratio of snail-spread areas in the hilly region was higher than that in lake region in other years. The average density of live snails was 0.0184-1.6617 no./0.1 m and 0.0028-0.2182 no./0.1 m in the hilly region. Among the 114 environments affected by floods, 86 consisted of hilly environments, including 66 spreading environments affected by rainstorm floods, and 20 rainstorm debris flow environments. There were 28 lake areas, of which 10 were in the Jiangxi section of Yangtze River and were affected by rainstorm floods. Snail spread following flooding has a certain 'lag effect,' and = simple annual changes in hydrological characteristics have little effect on the diffusion of snails or on their density = in the affected environment, but it is more closely related to local floods. The hilly environments are more susceptible to floods than the lake region, and the risk of snail spread is much higher in the hilly than in the lake region.
洪水是钉螺扩散的主要自然因素，对血吸虫病传播有负面影响。关于洪水后钉螺的扩散和迁移的研究较少；因此，我们旨在调查洪水对钉螺扩散的影响，并探索江西省钉螺扩散的特征和规律。通过回顾性调查和横断面调查，收集了2017年至2021年江西省钉螺扩散的数据。结合水文情况、地区类型和洪水类型，对钉螺扩散的分布、性质和面积进行了系统分析。2017年至2021年，共发现120个钉螺扩散环境，其中92个在丘陵地区，28个在湖区。由洪水和其他方式导致的扩散环境分别为6个和114个。复发、扩大和首次出现的比例分别为43.42%、38.16%和18.42%，14个新的钉螺环境仅分布在丘陵地区。除2018年外，其他年份丘陵地区钉螺扩散面积的比例高于湖区。丘陵地区活螺平均密度为0.0184 - 1.6617只/0.1平方米，湖区为0.0028 - 0.2182只/0.1平方米。在受洪水影响的114个环境中，86个为丘陵环境，其中66个为暴雨洪水影响的扩散环境，20个为暴雨泥石流环境。有28个湖区，其中10个在长江江西段，受暴雨洪水影响。洪水后钉螺扩散有一定的“滞后效应”，水文特征的简单年度变化对受影响环境中钉螺的扩散或密度影响较小，但与当地洪水关系更为密切。丘陵环境比湖区更容易受到洪水影响，丘陵地区钉螺扩散的风险远高于湖区。
