n. (pl. metacercariae) a mature form of the *cercaria larva of a fluke. Liver fluke metacercariae are enveloped by thin cysts and develop on various kinds of vegetation.
The common liver fluke. In tropical regions this species is replaced by F. gigantica. Like all trematodes, their intermediate hosts are aquatic snails. Infection occurs when the infective metacercariae are ingested on vegetation in swampy areas. Normal final (definitive) hosts are sheep, cattle and various wild animal species. Humans can acquire fascioliasis if they eat contamiated water cress etc.... fasciola hepatica
n. any of the parasitic flatworms belonging to the group Trematoda. Adult flukes, which have suckers for attachment to their host, are parasites of humans, occurring in the liver (liver flukes; see Fasciola), lungs (see Paragonimus), gut (see Heterophyes), and blood vessels (blood flukes; see Schistosoma) and often cause serious disease. Eggs, passed out with the host’s stools, hatch into larvae called *miracidia, which penetrate an intermediate snail host. Miracidia give rise asexually to *redia larvae and finally *cercariae in the snail’s tissues. The released cercariae may enter a second intermediate host (such as a fish or crustacean); form a cyst (*metacercaria) on vegetation; or directly penetrate the human skin.... fluke
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