Lo C T, Cross J H
Zhonghua Min Guo Wei Sheng Wu Xue Za Zhi. 1975 Dec;8(4):241-52.
Echinostoma revolutum from Taiwan was studied in lymneid snails at 29 +/- 0.5 degrees C. Given 3-5 miracidia, 95% of Lymnaea ollula and 40% of Lymnaea swinhoei became positive; the prepatent periods were 18 and 25 days, respectively. The following are based on the observations in Lymnaea ollula: The time required for miracidial penetration was about one hour. The sporocysts developed only in the ventricle of the snail but mother rediae developed in the heart and other organs. Mature daughter rediae were not found in the heart cavity. The sporocysts reached the ventricle within 3 days. Mother rediae were released after 6 days and daughter rediae after 8 days. Given 5 miracidia, 1-3 sporocysts reached the heart and 2-20 mother rediae were found per snail. The number of mature daughter rediae was usually 100-200 although more than a thousand may develop in a snail. The sporocysts and mother rediae attained maximal size 9 days postinfection and started degeneration 13 days postinfection. Daughter rediae were largest at the beginning of cercarial emergence and decreased in size thereafter. Simultaneous production of daughter rediae and cercariae by the mother redia was seen only once in this snail mature cercariae were obtained in 10 days postinfection. The cercariae emerged from a small area of mantle collar near the posterior corner of shell aperture. They were negatively phototactic and positively geotactic. An estimation showed that each snail shed about 350 cercariae a day. The cercariae reached the pericardial cavity of snail in one hour via the renal orifice and metacercariae were seen 4-5 hours after exposure. The infectivity of cercariae at various times after shedding, as expressed by cyst recovery rates, were: 51.6%, O-hr old; 76.1%, 2-hr; 68% 4-hr; 32%, 6-hr; 3%, 8 and 10-hr. Cyst recovery rates were not different within the dosage of 50-500 cercariae per snail. Most metacercariae recovered 1-2 days after cercarial exposure were viable; only 5 among 6,533 cysts were dead.
对来自台湾的卷棘口吸虫在29±0.5摄氏度的椎实螺中进行了研究。给予3 - 5个毛蚴，95%的奥氏椎实螺和40%的斯氏椎实螺呈阳性；潜伏期分别为18天和25天。以下是基于对奥氏椎实螺的观察结果：毛蚴穿透所需时间约为1小时。子胞蚴仅在螺的心室中发育，但母雷蚴在心脏和其他器官中发育。在心腔内未发现成熟的子雷蚴。子胞蚴在3天内到达心室。母雷蚴在6天后释放，子雷蚴在8天后释放。给予5个毛蚴，1 - 3个子胞蚴到达心脏，每只螺中发现2 - 20个母雷蚴。成熟子雷蚴的数量通常为100 - 200个，尽管一只螺中可能发育出超过一千个。子胞蚴和母雷蚴在感染后9天达到最大尺寸，并在感染后13天开始退化。子雷蚴在尾蚴逸出开始时最大，此后尺寸减小。在这种螺中，母雷蚴同时产生子雷蚴和尾蚴仅出现过一次；在感染后10天获得成熟尾蚴。尾蚴从壳口后角附近的一小片外套膜领处逸出。它们具有负趋光性和正趋地性。一项估计表明，每只螺每天排出约350个尾蚴。尾蚴在1小时内通过肾孔到达螺的心包腔，暴露后4 - 5小时可见囊蚴。以囊蚴回收率表示，尾蚴排出后不同时间的感染力分别为：0小时龄，51.6%；2小时，76.1%；4小时，68%；6小时，32%；8小时和10小时，3%。在每只螺50 - 500个尾蚴的剂量范围内，囊蚴回收率没有差异。大多数在尾蚴暴露后1 - 2天回收的囊蚴是活的；在6533个囊蚴中只有5个死亡。
