Studies on Immunopathological, Epidemiological Analysis and Control of Schistosomiasis Japonica in the Endemic Area Around Dong-Ting Lake.

为分析洞庭湖地区血吸虫病流行情况，选择洞庭湖区血吸虫病低流行阶段(A)、低流行阶段(B)和高流行阶段(C)三种疫源地。两个病源地(A)和(B)的患病率分别为20.6%和18.9%，而C病源地的患病率约为50%。在疫源地(A)和(B)中，农业从业人员的阳性率较高，而疫源地(C)的渔民和小学生粪检阳性率较高。每个粪便的产卵量与症状之间的关系非常显著。该病在牛、猪、狗、猫等家畜中也有较高的患病率。应强调在控制措施下对感染动物进行管理的必要性。我们调查了吡喹酮治疗患者血清抗体的变化。结果表明，治疗成功后，抗体滴度显著下降。用ELISA法和Western-blotting法检测血清抗体，对评价治疗效果和进行血清流行病学分析具有重要意义。我们研究了中国地区血吸虫病患者血清中的Ig G独特型，以评价体外抗独特型T细胞免疫应答。感染血清中功能独特型的出现具有异质性，其独特型活性与治疗和血吸虫卵抗体滴度无关。这些结果表明，独特型活动可能提供独一无二的信息，反映日本血吸虫病的临床差异。为达到媒介钉螺控制的目的，调查了钉螺的原虫寄生虫，但没有发现致病原虫。试验了几种农用药物对钉螺的杀灭效果。结果表明，百威和三溴沙兰可能是一种潜在的灭螺药物。

To analyze the epidemiological situation, three kinds of schistosomiasis foci, the areas in low prevalent phase (A) and (B) and the area in high prevalent phase (C) in the endemic area around the Dong-ting Lake, were selected. Prevalences of the disease were 20.6% and 18.9% in the two foci (A) and (B), respectively, but about 50% in the focus (C). In the foci (A) and (B), the positive rate was high among the people engaged in agriculture, whereas fishermen and pupils in the focus (C) were highly positive on faecal examination. The relation between the number of eggs per faeces and the symptoms was clearly significant. The disease was also found at high prevalence rate in some domestic animals such as cattle, pigs, dogs and cats. The need for managing the infected animals under the control measures should be stressed.We investigated the change of serum antibodies in patients treated with Praziquantel. The data suggested that the successful treatment resulted in remarkable decrease of the antibody titer. The tests for serum antibody by highly specific techniques such as ELISA and Western-Blotting seemed useful for evaluation of the effect of the treatment and for seroepidemiological analysis.We studied IgG idiotypes in sera of schistosomiasis patients in China for evaluating anti-idiotypic T cell response in vitro. There was a heterogeneity in appearance of functional idiotypes in infected sera, and the idiotypic activities were independent of treatment and antibody-titers to schistosome egg. Those results suggest that idiotypic activities might give an unique information showing the clinical difference of schistosomiasis japonica.For the purpose of vector snail control, protozoan parasites of the snail were investigated but the pathogenic ones were not found. Molluscicidal effects of some agricultural drugs were tested on the snials. The results suggest that Cartap and Tribromosalan seem to be potential molluscicides for the control of the snails