Investigation and analysis of present situation of historical oncomelania environment in Dongtai, Jiangsu

Abstract

Objective To understand the distribution of historical oncomelania environment in Dongtai City, and we provide scientific basis for making scientific and effective surveillance and control of schistosomiasis at the stage of eliminating the target.

Methods The current situation of the historical oncomelania environment in the whole city was investigated, and the information of the historical oncomelania situation and the previous situation of oncomelania control were recorded. For all verified registered environments, conduct on-site verification of oncomelanias and record the environmental evolution. The database was established and statistical analysis was carried out. Meanwhile, Google Earth was used to mark and manage the landmarks.

Results The historical oncomelania environment in Dongtai City is distributed in 224 villages of 14 towns. There are 39 133 historical oncomelania environments in Dongtai City, with a historical oncomelania area of 22 284.99 hm ². Among them, Touzao town has the largest environmental number and area, with 12 297 in number and 8 080.856 4 hm ² in area, accounting for 31.42% and 36.26% of the city’s total respectively. The environmental evolution is mainly of class II and class III. The environmental number and area account for 97.68% and 61.38% of the total. The environmental types are mainly ditches and ponds, with the environmental number and area accounting for 88.59% and 27.48% of the total respectively. Oncomelania were found in 12 historical oncomelania environments, covering an area of 2.4 hm ², which is a recurrence of oncomelanias in 5-25 years. There were 11 ditches and 1 pond, there was no significant difference in the recurrence of different environmental types (χ ²=1.704, P=0.192).

Conclusion Dongtai City has a large area and wide distribution of historical oncomelania environment,and most of them are still suitable for oncomelania breeding. In areas where schistosomiasis is eliminated, more efforts should be made to improve the environment, remoulding the breeding environment of Oncomelania. At the same time, oncomelania condition and disease monitoring should still be the focus of the work in this area.

Abstract

摘要： 目的 掌握东台市历史有螺环境分布现状, 为消除达标阶段如何制定科学有效的血吸虫病监测与控制提供科学依据。 方法 对全市历史有螺环境进行现状调查, 记录历史螺情信息和既往查灭螺情况。对所有已经核实登记的环境, 进行现场螺情核实, 记录环境演变情况。建立数据库并进行统计分析, 同时采用Google Earth进行地标文件标注管理。 结果 东台市历史有螺环境分布在14个镇场224 村。现存历史有螺环境39 133个, 历史有螺面积22 284.99hm2, 其中环境数和面积最大的均为头灶镇, 数量12 297个, 面积8 080.856 4 hm2, 分别占全市总数的31.42%和36.26%。环境演变以Ⅱ类、Ⅲ类为主, 环境数、环境面积占总数的97.68%、61.38%, 环境类型以沟渠、堰塘为主, 环境数及面积分别占总数的88.59%, 27.48%。发现历史有螺环境复现12处, 面积2.4 hm2, 为5~25年的历史有螺环境复现。其中沟渠11个和堰塘1个, 不同环境类型钉螺复现差异无统计学意义 ( χ2=1.704, P=0.192) 。 结论 东台市历史有螺环境面积较大、分布较广, 且大多数仍以适合钉螺孳生的环境存在。血吸虫病消除地区仍需要加大进一步环境改造力度, 彻底改造钉螺孳生环境, 同时螺情及病情监测仍应作为该地区的工作重点。