实验采用白昼逸出尾蚴早期型和晚期型的曼氏血吸虫Sm(E)株与Sm(L)株,前者来源于人宿主,保种于光滑双脐螺体内;后者则来源于自然感染的黑家鼠。此外,还用夜间逸出尾蚴的罗氏血吸虫Sr(N)株,保种于光滑双脐螺体内。亲代杂交是将自螺体逸出的尾蚴确定性别后,各以100条按下述三种组合感染小鼠:sm♀(E)×Sr♂(N);Sm♀(L)×Sr♂(N); In the experiment, the Sm (E) and Sm (L) strains of early and late-stage Schistosoma mansoni were released during the daytime. The former was derived from human hosts and was maintained in a smooth-bodied umbilical snail. The latter was derived from naturally infected Black house mouse. In addition, Src (R) Schistosoma japonicum (C Schistosoma japonicum) strain escaped cercariae at night and maintained in a smooth, smooth-bodied umbilical snail. After the hybridization of the parental line, the cercariae escaping from the spirochetes were tested for sex and each of the 100 mice was infected with the following three combinations: sm♀ (E) × Sr♂ (N); Sm♀ (L) × Sr♂ ( N);