摘要
吸虫（吸虫纲）是不分节的、有2个吸口的片状蠕虫。感染是人畜共患病（传入动物病）；人类由于进食被污染的食物而意外感染。在一些地区有大量人被感染。淡水螺是这些感染的中间宿主。吸虫是雌雄同体，因此即使轻度感染也产卵。成虫不复制；重度感染由大量或重复食入传染性后囊蚴引起。因此，典型的患者并非旅行者而是当地人（如难民）。注意酱油、浸酸、发酵和酒精腌泡都不能杀死鱼或甲壳类动物上的后囊蚴，而这些是亚洲和其他地区传统饮食的一部分。
Flukes （trematodes） are unsegmented, leaf-shaped worms with two suckers. The infections are zoonoses （diseases of animals）; humans are accidentally infected by eating contaminated foods. In some areas, huge numbers of individuals are infected. In all of these infections, freshwater snails are intermediate hosts. The flukes are hermaphrodites, so even light infections produce eggs. The adults do not replicate; heavy infections are caused by heavy or repeated ingestion of infective metacercariae. Thus, the typical patient is not a tourist but an indigenous individual （e.g. a refugee）. Note that soy sauce, pickling, fermenting and alcohol marinades do not kill the metacercariae on fish and crustaceans, which are a traditional part of the diet in Asia and elsewhere.
