Flukes (Trematodes) Introduction
The immature eggs are discharged from human feces and reach fresh water, hatching after 3-7 weeks and forming miracidia. Upon contact with host snails, the miracidia penetrate the soft tissues and form sporocysts, first- and second-generation rediae, and, lastly, cercariae. The cercariae encyst on various plants such as water caltrop, water chestnut, lotus (on the roots), water bamboo, and other aquatic vegetables. Humans are infected by consuming these raw vegetables. In the human duodenum, the metacercariae attach to the walls and become adult worms in approximately 3 months.