The life cycle of Schistosoma species (S. mansoni, S. japonicum, and S. haematobium) begins when eggs are shed in host feces or urine. In water, these eggs hatch into miracidia, which infect freshwater snails and develop into sporocysts. The snails then release free-swimming, infective cercariae that penetrate human skin, losing their tails to become schistosomulae. These larvae enter the bloodstream, mature in the liver's portal blood, and migrate to mesenteric venules (S. mansoni and S. japonicum) or the bladder's venous plexus (S. haematobium) to lay eggs.