Epidemiology and control of marshland-type schistosomiasis

对中国湖滩型日本血吸虫病流行区进行了流行病学分析。本次合作研究项目的目的是了解研究地区血吸虫病的流行模式，确定感染的危险因素，并制定有效的防治对策。我们在湖南省仁江村进行了调查，该村人口规模为1144人，该村位于扬子江边很长一段时间。采集居民血、尿标本，检测抗体滴度、人类白细胞抗原和肿瘤坏死因子-α作为遗传标志物，以及血清IV型胶原和间质金属蛋白酶-2水平。按WHO标准对日本血吸虫感染所致肝纤维化进行超声诊断，随机抽查500名居民，连续两年检测180人，阳性率为26.8%，提示既往有日本血吸虫感染史。SEROP…(A)男性、(B)成人和(C)农民的阳性率显著升高。本组人群的水接触率明显较高，18个月内再感染率明显较高。虽然我们研究了该村钉螺中间宿主的栖息地，但由于该村面积太小(1.48平方公里)，我们没有观察到钉螺分布强度与血清阳性率之间的显著相关性。我们试图建立新的方法来评估流行病学参数，检测尿中血吸虫抗原和抗血吸虫抗体，以及检测与肝纤维化程度相关的血清参数。我们观察到尿液抗体水平与血清抗体水平显著相关。血清IV型胶原和基质金属蛋白酶-2水平也与肝纤维化程度相关。这些结果表明，由于易于操作和成本效益，它们在流行病学研究中可能有用。较少

Epidemiological analysis was done in an endemic area of marshland-type achistosomiasis japonica in China. The aim of this cooperative research project was to characterize endemic patterns of schistosomiasis in the studied area, to identify risk factors for the infection, and to develop effective countermeasure for this disease. We did survey in Rinjiang village, Hunan Province, of which population size was 1,144, and the village is located a long with the Yangzhi river. We collected blood and urine samples from residents, and tested for antibody titers, HLA and TNF-alpha as genetic markers, and serum level of type IV collagen and mesenchimal metaroproteinase-2 (MMP-2). Hepatic fibrosis induced by Schistosoma japonicum infection was diagnosed ultrasonographically based on the criteria of WHO.We tested 500 residents randomly, and 180 were tested consecutively in the two years.Of the tested subjects, 26.8% were seropositive for S.japonicum, indicating past infection of the parasite. Serop … More ositive rate was significantly elevated in (a) males, (b) adults and (c) farmers. Individuals belong to this group showed significantly high water-contact, and at the same time reinfection rate in these 18 months was significantly high in this group. Although we studied habitant areas of the intermediate snail hosts in this village, we did not observed significant association between seropositive rate and intensity of snail distribution possible because the village was too small (1.48km^2).We tried to develop new method for evaluating epiodemiological parameters ; detection of schistosome antigens and anti-schistosome antibodies in urine and detecting serum parameters correlated with degree of hepatic fibrosis. We observed that antibody level in urine showed significant association with that of serum antibody. Serum levels of type IV collagen and MMP-2 were also correlated with degree of hepatic fibrosis. Those results suggests their probable usefulness in epidemiological study because of the easy handling and cost-effectiveness. Less