- A genus of large, heavy-bodied roundworms parasitic in the small intestine; abundant in humans and many other vertebrates. [G. askaris, an intestinal worm]- A. equorum SYN: Parascaris equorum.- A. lumbricoides a large roundworm of humans, one of the commonest human parasites (8–12 inches in length); various symptoms such as restlessness, fever, and sometimes diarrhea are attributed to its presence, but usually it causes no definite symptoms; the similar species, A. suum (or A. lumbricoides suum) is very common in swine, but is not readily transmitted to humans, and vice versa; the types are morphologically and immunologically similar but apparently are host-adapted types, considered distinct species or races.
* * *as·ca·ris 'as-kə-rəs n1) cap a genus of Ascaridae comprising nematode worms having a 3-lipped mouth, resembling earthworms in size and superficial appearance, and including one (A. lumbricoides) parasitic in the human intestine2) pl as·car·i·des ə-'skar-ə-.dēz ASCARID
* * *n.a genus of parasitic nematode worms. A. lumbricoides, widely distributed throughout the world, is the largest of the human intestinal nematodes - an adult female measures up to 35 cm in length. Eggs, passed out in the stools, may be transmitted to a new host in contaminated food or drink. Larvae hatch out in the intestine and then undergo a complicated migration, via the hepatic portal vein, liver, heart, lungs, windpipe, and pharynx, before returning to the intestine where they later develop into adult worms (see also ascariasis).
* * *As·ca·ris (asґkə-ris) [L., from Gr. askaris] a genus of large intestinal nematode parasites of the family Ascarididae.
Medical dictionary. 2011.