移民建镇单退与双退地区血吸虫病疫情动态观察

Epidemic dynamics of schistosomiasis after relocating people to build township in river beach regions

目的了解单退型（退人不退耕）和双退型（退人退耕）移民建镇项目实施对血吸虫病流行的影响。方法在两个已实施了单退型和双退型移民建镇项目的血吸虫病流行村，于2002～2005年进行螺情、滩地污染、人畜血吸虫感染等连续4年的纵向观察。结果单退点江心村感染性钉螺平均密度逐年下降；野粪阳性率和牛感染率分别由2002年的11．86％、14．29％降至2005年的8．17％、7．23％，但两者差异无统计学意义（P〉0．05）；该村4年的人群感染率在3．05%～4．83％间波动。双退点江洲村滩地除2005年外，前3年均检获阳性螺；人群粪检阳性率2003年（1．54％）较2002年（3．11％）下降了50．50％（P〈0．05），其后2年徘徊在1％左右。两村人群粪检阳性率2002年差异无统计学意义（江心村：4．83％，江洲村：3．11％，P〉0．05），其后3年江洲村均低于江心村（P均〈0．05）。结论双退点血吸虫病疫情近期有所下降，而单退点无明显变化。

Objective To understand the influences of the flood protection program-relocating people to build township on schistosomiasis transmission in endemic areas. Methods Two villages, Jiangxin with resettlement but remaining arable lands, and Jiangzhou with resettlement and converting cultivated land back to forest or grassland, were selected as pilot fields. Four-year （2002- 2005） successive survey was carried out to monitor snail situation, the contamination of marshland by wild faeces, and the schistosomiasis prevalence in human and cattle, etc. Results At Jiangxin, there was a descending tendency of the density of infected snails year by year. The hatching positive rate of wild faeces and bovine infection rate of schistosome decreased from 11.86%, 14.29% of 2002 to 8.17%, 7.23% of 2005, respectively, but with no statistical significances. The human infection rate of schistosome of Jiangxin fluctuated （3.05 % -4. 83 % ） with no significance among four years. At Jiangzhou, the density of infected snails fell down to zero in 2005, and the human infection rate significantly declined from 3.11% of 2002 to 1.54% of 2003,and swung around 1% at the latter 2 years. There was no statistical significance of the human infection rate of schistosome between Jiangxin and Jiangzhou in 2002 （Jiangxin ： 4. 83 %, Jiangzhou ： 3.11%, P 〉 0. 05）, but the former was statistically higher than the latter from 2003-2005. Conclusions There is no obvious variation of the schistosome epidemicity at Jiangxin after resettlement but remaining arable land, while the epidemicity of Jiangzhou, after resettlement and converting cultivated land to forest or grassland, declines in some degree.