S. mansoni, S. haematobium, S. japonicus. Use water snail as intermediate host (can also have secondary host)
Egg dropped in faeces and mature in soil. they are ingested and hatch in intestine. they penetrate the gut wall and migrate to liver then heart then lung. they grow and are then coughed up and swallowed.10-30cm adult can escape from any orifice though larval migration causes most morbidity.
Th2 (IL-4,5 & 13) and Eosinophil driven. Hyperresponsiveness