血吸虫是一种缐状,有吸盤、雌雄异体、复生性的吸虫,寄生在哺乳动物(主要是人)的肠系膜静脉及门脉系统的小血管内,依靠血液作营养。雌雄常合抱,雌虫在肠系膜静脉内产卵,部分虫卵逆流到肠组织内.经小溃疡至肠腔随粪便排出体外,如有机会入水,在适宜的温度和条件下孵出毛蚴,碰到钉螺蛳时即侵入其体内,发育成母胞蚴,繁殖为子胞蚴,长出尾蚴逸出,在岸旁水面游动。当农人踝腿在水田中耕作,渔夫涉水捞鱼,儿童在河中洗澡嬉戏,妇女在河滩洗澡时,尾蚴即乘机侵入皮肤或粘膜,循血流至肝到肠系膜静脉,发育为成 Schistosoma japonicum is a pincer-like, sucker, dioecious, and retroviruse fluke that parasites in the small blood vessels of the mesenteric and portal system of mammals (mainly humans) and relies on blood for nourishment. Female and male together, the female spawns in the mesenteric vein, part of the eggs countercurrent to the intestine.Through the small ulcer to the intestine with the excretion of the body, such as the opportunity to enter the water, hatch magma under the appropriate temperature and conditions, touch Incomelanoschis that invade its body, develop into mother’s egg larvae, reproduction as a child of cercariae, grow cercariae to escape, swimming in the water near the shore. When the farmer’s ankle and leg are cultivated in the paddy field, the fisherman takes water to fish and the child plays in the river. When the woman takes a bath in the river bank, the cercariae takes the opportunity to invade the skin or mucous membrane, and then flows to the liver through the bloodstream to the mesenteric vein