trichina

/tri kuy"neuh/, n., pl. trichinae /-nee/.

a nematode, Trichinella spiralis, the adults of which live in the intestine and produce larvae that encyst in the muscle tissue, esp. in pigs, rats, and humans.

[1825-35; < NL < Gk tríchina, n. use of fem. of tríchinos of hair. See TRICH-, -INE¹]

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Species (Trichinella spiralis) of parasitic nematode, found worldwide, that causes the disease trichinosis.

Trichinae (or trichinas), 0.06–0.2 in. (1.5–4 mm) long, mate in the host's small intestine. Fertilized females penetrate the intestinal wall and release larvae, which the blood carries throughout the body. The larvae grow, mature, and become encysted within muscle tissue. The digestive juices of an animal that eats the muscle tissue break down the cyst, liberating the larvae for further development; the worms mature, and the cycle begins again.

Trichina encysted in muscle

Russ Kinne-Photo Researchers/EB Inc.

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▪ worm

plural  trichinae, or trichinas 

      (species Trichinella spiralis), parasitic worm of the phylum Nematoda that causes trichinosis (q.v.), a serious disease in humans and other mammals—e.g., pigs, cats, dogs, bears, foxes, and rats. The worm, which occurs all over the world, ranges in length from 1.5 to 4 mm (0.06 to 0.2 inch).

      Mating takes place in the host's small intestine, after which the fertilized female trichinae burrow into the intestinal wall and release the larvae. The larvae, in turn, are transported by the bloodstream to all parts of the body. The worm grows within muscle tissue, requiring approximately 16 days to mature. A cyst develops around the larva's body. Further development occurs if the muscle tissue containing the encysted larva is eaten by an appropriate host; the worm matures and reproduces in the host's intestine.

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