Tapeworms are parasites that sometimes infest pigs, cattle, and fish.
They can be passed on to a human who eats infested pork, beef, or fish that has not been adequately cooked. Once in the intestines, a tapeworm can anchor itself by embedding its head end into the intestinal wall. The tapeworm then absorbs food and may grow to more than 10 metres long. Segments of the worm break off and are excreted in stools. If the worm remains in the intestines, it often causes symptoms such as weight loss, occasional abdominal pain, loss of appetite, and irritation around the anus.