Begins with an egg, found in faeces, sputum, or urine of definitive host. Can be non-embryonated (immature) or embryonated (ready to hatch). Hatch in environment (water) or within a host (typically mollusc).
Miracidium (pleural: miracidia): hatchling, a free-swimming ciliated larvae. No mouth, cannot eat, therefore need to find a host quickly if hatch in the environment.
Grow and develop within intermediate host into an elongated sac-like structure called a sporocyst.
Cercaria (plural: cercariae): larval form of trematode (develops within geminal cells of sporocyst). May or may not have swimming tail. Motile cercaria finds and settles in a host where it will become either depending on the species, an:
adult (fully developed mature stage capable of sexual reproduction)
metacercariae (cercaria encysted and resting, only when there are 3 intermediate host cycles) or
mesocercariae (encysted stage either on vegetation or in a host tissue on the 2nd intermediate host. Parasite able to infect definitive host by consuming 2nd intermediate host that has metacercariae on/in it)
Life-cycle stages of Schistosoma Japonicum
Schistosoma spp, Exposure to fresh water (skin penetration)
Lung / tissue flukes
Paragominas spp. (lung fluke), raw or undercooked crab or other crustaceans
Fasciolia (liver fluke), watercress
Fasciolopsis, metagonimus etc.