Another name for a tapeworm infection is taeniasis. It is caused by a parasite that lives in the bowels of cows or pigs. The infection passes to humans by eating undercooked or raw beef or pork. It is more common in areas where there is poor sanitation. Tapeworms live inside your bowels. You may not have any signs. You may not know that you have them until you see parts of the tapeworms in your stools. If tapeworm eggs are swallowed, they may move in the body to your brain, eyes, or heart. This may be very serious. Treating a tapeworm early can lower the chance of you having problems later on.