Kleshas are a state of mind.
Trematodes or flukes are small parasitic flatworms that use vertebrates as their definitive host , and molluscs -LRB- usually freshwater snails or land snails -RRB- as their intermediate host .. Trematodes. Trematoda. flatworms. flatworms. host. Host ( biology ). To accomplish this , they have several varied life cycle stages .. life cycle. Biological life cycle. The life cycle of a typical digenean trematode can be thought to begin when its egg is immersed in water .. life cycle. Biological life cycle. digenean. digenean. Following this , a miracidium hatches , which swims to find a mollusc host .. host. Host ( biology ). mollusc. mollusc. miracidium. miracidium. The miracidia go through several stages in the mollusc host , eventually emerging as motile cercarial larvae .. host. Host ( biology ). mollusc. mollusc. The cercaria either infects vertebrates through the skin or is ingested .. cercaria. cercaria. In its vertebrate host , the cercaria matures to an adult form , the fluke , and lays eggs that are discharged with the host feces or urine .. vertebrate. vertebrate. host. Host ( biology ). cercaria. cercaria. feces. feces. urine. urine. In the presence of open water , the eggs hatch and the miracidium stage of life is reached again .. miracidium. miracidium