四川省血吸虫病流行区钉螺现况调查

Investigation on current distribution of Oncomelania snails in schistosomiasis-endemic areas of Sichuan Province

目的了解四川省钉螺分布现状,为制定全省消除血吸虫病策略、实施精准血防措施提供科学依据。方法按照《全国钉螺调查方案》和《四川省钉螺调查方案》要求,2016–2017年对四川省现有钉螺环境、历史有螺环境和可疑钉螺孳生环境,采用系统抽样法进行螺情调查,并对调查结果进行分析。结果 2016–2017年四川省共调查血吸虫病流行区的88 346处环境,共查出有螺环境19 314处,有螺面积4 829.25 hm^2,未发现血吸虫感染性钉螺。全省共设钉螺调查框3 017 915框,发现活螺框1 041 417框,共捕获活螺1 791 115只,全省平均活螺框出现率为34.51%,平均活螺密度为0.59只/0.1 m2。查出的现有钉螺环境分布于9个流行市(州)的54个流行县(市、区)、377个乡(镇)、1 704个流行村。有钉螺分布的环境类型以沟渠型为主(占70.22%),植被类型以杂草为主(占66.45%)。全省首次发现钉螺和首次发现血吸虫感染性钉螺的年份分别是1913年和1956年,最近一次查见感染性钉螺年份为2008年。结论四川省适宜钉螺孳生的环境仍较多,今后应加强钉螺监测和控制工作。

Objective To understand the current distribution of Oncomelania snails in Sichuan Province,so as to provide scientific evidence for formulating the schistosomiasis elimination strategy and implementing the precision schistosomiasis control measures in the province.Methods According to the National Scheme on Oncomelania hupensis Snails in China and the Scheme on Oncomelania hupensis Snails in Sichuan Province,snail surveys were performed in current snail habitats,historical snail habitats and suspected snail habitats using systematic sampling in Sichuan Province from 2016 to 2017,and the survey results were analyzed.Results From 2016 to 2017,a total of 88 346 settings were surveyed in schistosomiasis-endemic areas of Sichuan Province,and 19 314 settings were detected with snails,covering an area of 4 829.25 hm^2,with no Schistosoma japonicum infection identified in snails.A total of 3 017 915 frames were investigated in Sichuan Province,and 1 041 417 frames were found to have living snails,with totally 1 791 115 living snails captured.The mean density of living snails was 0.59 snails/0.1 m2,and the mean percentage of frames with living snails was 34.51%in Sichuan Province.The current snail habitats were mainly distributed in 1 704 villages,377 townships,54 counties(districts)of 9 cities(prefectures)across the schistosomiasis-endemic areas of Sichuan Province.Snail habitats were mainly found in ditches(70.22%),and weeds were the predominant vegetation in snail habitats(66.45%).Snails were firstly discovered in Sichuan Province in 1913,and S.japonicum-infected snails were firstly identified in 1956,with the latest identification of S.japonicum-infected snails in 2008.Conclusion There are many settings suitable for snail breeding in Sichuan Province,and snail monitoring and control should be intensified in the future.