A tapeworm is a ribbon-shaped parasite that lives in human or animal intestines. They are uncommon in developed countries. There are a number of different types which all have slightly different life cycles.
Tapeworm infection can come from animals such as pigs, sheep, cattle, fish, dogs and cats. Eating undercooked food contaminated with tapeworm cysts and eggs causes the infection.
Tapeworm eggs are shed in stools and it is possible for infection to spread from person to person through the oral/anal route.