n. a genus of large tropical parasitic *flukes that are particularly prevalent in the Far East. The adults of P. westermani live in the human lungs, where they cause destruction and bleeding of the tissues (see paragonimiasis). However, they may also be found in other organs of the body. Eggs are passed out in the sputum and the larvae undergo their development in two other hosts, a snail and a crab.
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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