<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> 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>
miracidium is a larval stage in the development of
miracidium is a larval stage in the development of
trematode
trematode