Humans as Definitive Host Hermaphroditic adult fluke releases eggs into human lung ⑧Infected crayfish is Adult fluke eaten by human,and (7.5-12 mm long metacercaria develops Metacercaria into adult fluke (0.25-0.5mm) In crayfish,cercaria encysts to produce metacercaria Sexual reproduction Eg9s● ②Eggs reach water Definitive host after being excreted in feces Intermediate host Cercaria leaves ④Free-swimming miracidium snail and enters enters snail Miracidium develops crayfish in egg and hatches from egg Cercaria Intermediate host Redia Inside snail,miracidium develops into redia,which reproduces asexually Cercaria Asexual Miracidium to produce rediae:several (0.5 mm long) reproduction (0.8mm long) cercaria develop within redia Figure 12.26 Humans as Definitive Host Figure 12.26