<P> Trematodes are any parasitic flatworm of the class Trematoda, especially a parasitic fluke . While consisting of two suckers, one being ventral and one being oral . They have a tegument covering which helps them with absorption and protection from the environment . </P> <P> The life cycle of a typical trematode begins when the egg is immersed in water or from the adult worms in the definitive host . Some trematode eggs hatch in water, others are eaten by the first intermediate host and hatch within that host, so there are many different routes that a trematode could take to infect a host . Following this, the miracidium, which is free - swimming ciliated larva that a parasite moves from the egg to host stage, hatches which then also goes to find the mollusc host as the first intermediate host . This is where either a rediae or sporocyst will form depending on the host and if there is competition between the two . This eventually forms into a motile cercariae . The cercariae then either infects vertebrates through the skin of a host or is ingested and aims to locate the second intermediate host . When in the vertebrate host, the cercariae can then form into an adult, metacercariae or mesocercariae, depending on the life cycle, or is rejected through feces or urine . Then the metacercariae and second intermediate host has to be ingested by the definitive host for the life cycle to be completed . </P> <P> While the details vary with each species, the general life cycle stages are: </P>

Miracidium is a larval stage in the development of