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以1、5、10、20和40只5组不同数量的血吸虫毛蚴分别感染单只阴性钉螺后,对钉螺感染率、感染螺的逸蚴率,逸蚴量及存活时间等进行观察,结果进一步证实了钉螺感染率的高低与毛蚴数量的多少呈相一致的趋势。感染螺的尾蚴逸出率具有明显的季节性变化。观察的250只感染螺在4,064次逸蚴中,共逸出尾蚴287,213条,平均每螺每次逸蚴70.67条。每只感染螺在本次观察的整个生存期间中逸蚴数平均为1148.85±96.29条,最多为8.079条。5组感染螺平均逸蚴数之间无显著差别。感染螺的存活时间从毛蚴入侵螺体时计算,平均为214.25±9.89d,最长为936d(相当2年零7个月);从初次逸蚴时计算,平均为118.28±9.94d,最长为839d。各组感染螺的平均存活时间亦无显著差别。94.8％的感染螺均在开始逸蚴后1年内死亡。
After inoculating a single negative snail with 5, 10, 20, and 40 different numbers of 5 groups of Schistosoma japonicum, the infection rates of snails, the rates of larvae, the larvae of larvae and their survival time were observed. The results were further analyzed Confirmed the snail infection rate level and the number of miracidia consistent with the trend. The infection rate of cercariae spirochetes has obvious seasonal changes. A total of 287,213 cercariae were found in 4,064 larvae, with an average of 70.67 larvae per larvae. Each infected snail in this observation of the entire life of the Central larvae in an average of 1148.85 ± 96.29, a maximum of 8.079. There were no significant differences among the five groups in mean number of infected larvae. The survival time of infected snails was 214.25 ± 9.89d and the longest was 936 days (equivalent to 2 years and 7 months) when invading the spirochete. The mean value was 118.28 ± 9.94d from the first larvae, the longest For 839d. There was no significant difference in the average survival time of infection group in each group. 94.8% of the infected snails died within 1 year after the larva was started.