Trichinella spiralis

Trichinella spiralis The worm that causes trichinosis. Trichinella spiralis larvae can infest pigs and wild game. It hibernates in muscle tissue within a protective cyst. When a human or an animal eats meat that contains infective Trichinella cysts, the acid in the stomach dissolves the hard covering of the cyst and releases the worms. The worms pass into the small intestine and become mature within 1 or 2 days. After the adult worms mate, the females lay eggs. Eggs develop into immature worms, travel through the arteries, and are transported to muscles. Within the muscles, each worm curls into a ball and encysts (becomes enclosed in a capsule). Infection occurs when these encysted worms are consumed in meat, continuing the cycle. Also known as pork tapeworm. See also trichinosis.