Abstract:

Objective To explore the influencing factors of the formation of large?scale Oncomelania snail situation in Maogang Town，so as to provide the scientific evidence for improving snail surveillance in Shanghai. Methods The data about the geography，construction and use of floodgate，and snail status of Maogang Town and its surrounding areas，as well as the meteorology and hydrology of Songjiang District were collected and reviewed，and the factors influencing the formation of snail status were analyzed. Results The condition of water，soil and temperature in Maogang Town was suitable for snail breeding. By 1993，75% （18/24）of the mouths flowing to Huangpu River and its branches had been built. From 1991 to 2001，the average annual precipi? tation of Songjiang District was 7.44% higher than the usual condition. There were two basin?wide floods occurring in 1991 and 1999，respectively. The occurrence of tides reaching or exceeding the warning level（3.50 m）of Mishidu hydrology station was positively correlated with the rainfall in the flood season（between June and September，r = 0.903，P < 0.01） . Snails were found in some adjacent areas surrounding Maogang Town，and the snail situation peak occurred in early 1990s. In 2002，a large scale area （26.67 hm2 ）of snail habitats was detected，which was mainly distributed in the west of Maogang Town in the upstream of the Huangpu River. Conclusions The formation of large?scale snail?breeding area in Maogang Town probably is the result of the combined action of the construction and use of floodgates，increasing rainfall，floods，tides that frequently surpass warning level of Huangpu River and the snail status of upstream areas. It is necessary to pay more attention to the data collection，analysis and utili? zation about schistosomiasis?related natural and social factors. In addition，regular snail surveys are suggested in schistosomiasis non?endemic areas adjacent to snail?infested area.

Key words: Oncomelania snail； Schistosomiasis；Retrospective investigation； Influencing factor；Maogang Town

摘要：

目的 探索上海市松江区泖港镇大规模螺情形成的影响因素， 为改进上海市的螺情监测工作模式提供科学依据。方法 收集并查阅泖港镇地理、 水闸建设与利用以及松江区气象、 水文等资料， 了解泖港镇及周边地区螺情， 分析泖港镇大面积钉螺生成的原因。结果 泖港镇具备钉螺孳生所必需的水、 土壤、 温度等基本条件， 至1993年该镇通黄浦江及其支流的75%的河口已建成水闸； 1991-2001年松江区年均降水量较常年多7.44%； 1991年和1999年各发生了1次流域性洪水； 米市渡水文站达到或超过警戒水位 （3.50 m） 次数与汛期 （6-9月） 降水量呈正相关 （r = 0.903， P < 0.01）。该镇毗邻地区有钉螺发现， 并于20世纪90年代初期出现1次钉螺高峰。2002年泖港镇发现大面积钉螺孳生 （26.67 hm2 ）， 钉螺主要分布于黄浦江上游的泖西片圩。结论 泖港镇大规模螺情形成可能是水闸的建设与使用、 降水量增多、 洪水、 黄浦江潮位频繁超警戒水位和上游地区螺情综合作用的结果。建议有必要加强血吸虫病相关自然和社会因素资料收集、 分析和利用；在与有螺地区毗邻的非流行地区定期开展螺情监测。

关键词: 钉螺； 血吸虫病； 回顾性调查； 影响因素； 泖港镇