page_title: Trematode life cycle stages
section_title: Representations of life cycles of several different trematode species
hierarchical_section_title: Trematode life cycle stages / Representations of life cycles of several different trematode species
caption_attribution_description: Lifecycle stages of a typical trematode, Schistosoma japonicum.
context_page_description: Trematodes are parasitic flatworms of the class Trematoda, specifically parasitic flukes with two suckers: one ventral and the other oral. Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions.
  The life cycle of a typical trematode begins with an egg. Some trematode eggs hatch directly in the environment, while others are eaten and hatched within a host, typically a mollusc. The hatchling is called a miracidium, a free-swimming, ciliated larva. Miracidia will then grow and develop within the intermediate host into a sac-like structure known as a sporocyst or into rediae, either of which may give rise to free-swimming, motile cercariae larvae. The cercariae then could either infect a vertebrate host or a second intermediate host. Adult metacercariae or mesocercariae, depending on the individual trematode's life cycle, will then infect the vertebrate host or be rejected and excreted through the rejected host's faeces or urine.
caption: Life cycle stages of a digenean human parasite, Schistosoma japonicum
exif: {}