2008-2010年安徽省巢湖地区血吸虫病流行因素监测与疫情预警

目的了解安徽省血吸虫病潜在流行区巢湖地区血吸虫病流行因素动态变化,为该地区可能发生的突发疫情提供预警信息。方法 2008-2010年在巢湖东南沿岸的巢湖市居巢区设立固定监测点和流动监测点,采用血清学、病原学方法调查当地居民、流动人口及家畜血吸虫感染情况;在危险地带和可疑环境开展钉螺分布情况调查;在通江河道调查钉螺扩散情况;采用螺笼放养法,对钉螺在巢湖生存繁殖的可能性进行实验研究。结果 2008年采用间接血凝试验（IHA）检测当地居民301人,未发现阳性者;2008-2010年分别检测渔、船民等流动人口321、362人和306人,阳性率分别为3.74%、4.97%和2.94%;对血检阳性者进行粪检,阳性率分别为66.67%、50%和55.56%。采用塑料杯顶管孵化法分别检测当地及从疫区购进的家畜91头和92头,均未发现阳性。在危险地带共调查97.8hm^2,可疑环境调查193.62hm^2,均未发现钉螺;钉螺扩散调查表明,钉螺可通过漂浮物携带方式向巢湖扩散;现场放养实验表明,钉螺不仅可在巢湖生存,而且可以产卵繁殖。结论巢湖地区已发现血吸虫病输入性传染源;外源性钉螺向巢湖扩散并在湖区生存繁殖的可能性较大。因此,需加强对输入性传染源的监测与管理,并阻止钉螺向巢湖扩散,以降低血吸虫病在该地区传播的风险。

Surveillance and forecast of schistosomiasis transmission in Chaohu Lake area in Anhui Province, 2008-2010

Objective To understand the dynamic changes of the potential prevalent factors of schistosomiasis in Chaohu Lake area so as to provide forecast information on the outbreak of schistosomiasis in the area. Methods From 2008 to 2010, fixed and mobile surveillance sites in potential endemic areas of Juchao District in Chaohu City, which was located in the southeast side of Chaohu Lake, were selected, and the schistosomiasis infection situation of local people, mobile population and livestock were investigated by immunological assays and/or stool examinations. The distribution of Oncomelania snails was surveyed in risk areas and suspicious areas, the spreading patterns of Oncomelania snails were observed in rivers that directly connected with the Yangtze River, and the Oncomelania snails were raised in the cages on the beaches of Chaohu Lake and a control area, and their survival and reproduction capacity was observed. Results In 2008, a total of 301 local people were screened by IHA, and there were no positives. From 2008 to 2010, a total of 321, 362 and 306 mobile population were examined by IHA, respectively, and the positive rate of antibody were 3.74%, 4.97% and 2.94%, respectively. The antibody positives were tested by stool examinations, and the positive rates were 66.67%, 50% and 55.56%, respectively. A total of 91 local livestock and 92 livestock from endemic areas were examined respectively by the miracidium hatching method, and there were no positives. A total of 97.8 hm^2 risk areas and 193.62 hm^2 suspicious areas in the potential endemic area were surveyed respectively, but no Oncomelania snails were found. The investigation results on snail spreading patterns indicated that snails could spread into Chaohu Lake by adsorbing on floating debris. The field study revealed that Oncomelania snails could survive and reproduce in the Lake. Conclusions The imported infectious sources of schistosomiasis have been found in Chaohu Lake area, and the higher possibility of imported Oncomelania snails spreading into the Lake and surviving and reproducing in the lake is predicted. Therefore, effective measures should be taken to decrease the risks of schistosomiasis transmission in the potential endemic area.