湖北省四湖流域钉螺分布调查

目的　调查湖北省四湖流域钉螺分布，为制订钉螺控制措施提供科学依据。方法　采用回顾性调查和现况调查相结合的方法，于2016年春季对四湖流域钉螺分布现状进行调查。收集、分析2008-2018年四湖流域钉螺分布面积、人群和家畜血吸虫感染率等疫情指标，对钉螺分布面积与人畜血吸虫感染率的相关关系进行分析。结果　2016年，四湖流域的9个血吸虫病流行县（市、区）共有钉螺孳生环境16 003处，钉螺分布面积2.46亿m2；活螺平均密度0.622 5只/0.1 m2，其中以杂草型和沟渠型环境较高，分别为0.688 0只/0.1 m2和0.706 4只/0.1 m2。钉螺孳生环境中，现有螺环境（Ⅰ类环境）和历史有螺环境（Ⅱ ~ Ⅳ类环境）分别占53.03%和46.97%。旱地、滩地、水田等钉螺孳生环境改变较大，通过环境改造措施消灭钉螺的效果较好。2008-2018年，四湖流域钉螺分布面积与人群、家畜血吸虫感染率均呈正相关关系（r人群 = 0.842，P < 0.01；r家畜 = 0.695，P < 0.01）。结论　四湖流域实施以传染源控制为主的血吸虫病综合防治策略对钉螺控制效果较好，但仍面临螺情反弹的风险。

Survey of snail distribution in Four-lake Basin of Hubei Province

Objective　To investigate the distribution of Oncomelania snails in Four Lake Basin of Hubei Province, so as to provide scientific evidence for the development of snail control interventions. Methods　The snail distribution was surveyed by means of the retrospective study and cross?sectional survey in the Four Lake Basin in Spring of 2016. The data pertaining to the endemic situation of schistosomiasis were collected and analyzed in the Four Lake Basin from 2008 to 2018, and the associations of snail habitat areas with the prevalence of Schistosoma japonicum in humans and bovines were examined. Results　There were 16 003 snail habitats in the 9 schistosomiasis?endemic counties (districts) in the Four Lake Basin in 2016, covering an area of 246 million m2. The mean density of living snails was 0.622 5 snails/0.1 m2, which was relatively high in weed?type settings (0.688 0 snails/0.1 m2) and ditches (0.706 4 snails/0.1 m2). Type I (current snail habitats, 53.03%) and II/III (historical snail habitats, 46.97%) settings were predominant snail habitats. A big change was seen in snail habitats in dry farmland, marshland and paddy farmland, and environmental modification resulted in satisfactory snail control effectiveness. In addition, the area of snail habitats positively correlated with the changes in the prevalence of S. japonicum infections in humans (r = 0.842, P < 0.01) and livestock (r = 0.695, P < 0.01). Conclusions　The integrate strategy with an emphasis on the control of the source of S. japonicum infections results in remarkable snail control effectiveness in the Four Lake Basin; however, there is a risk of re?emerging snail habitats.