Any species of worm that has a flattened shape.
Two types of flatworm are parasites of humans: cestodes (tapeworms) and trematodes (flukes, schistosomes; see liver fluke; schistosomiasis).
(platyhelminth) n. any of the flat-bodied worms, including the *flukes and *tapeworms. Both these groups contain many parasites of medical importance.
Tapeworms, which are segmented Platyhelminths (Flatworms) consisting, in their adult stage, of a scolex for attachment to the gut of the final host, an unsegmented neck region and a long segmented strobila consisting of immature, mature and gravid proglottids (segments).... cestoda
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
(cestode) n. any of a group of flatworms that have a long thin ribbon-like body and live as parasites in the intestines of humans and other vertebrates. The body of a tapeworm consists of a head (scolex), a short neck, and a strobila made up of a chain of separate segments (proglottides). Mature proglottides, full of eggs, are released from the free end of the worm and pass out in the host’s stools. Eggs are then ingested by an intermediate host, in whose tissues the larval stages develop (see plerocercoid; cysticercus; hydatid). Humans are the primary hosts for some tapeworms (see Taenia; Hymenolepis). However, other genera are also medically important (see Diphyllobothrium; Dipylidium; Echinococcus).... tapeworm
n. any member of several groups of soft-bodied legless animals, including flatworms, nematode worms, earthworms, and leeches, that were formerly thought to be closely related and classified as a single group – Vermes.... worm