Tapeworms are parasites that can live in people's intestines (bowel). They belong to a class of worms called cestoda, so are known medically as cestodes.
Tapeworms tend to be flat, segmented and ribbon-like. Humans can catch them by touching contaminated stools and placing their hands near their mouth, by swallowing food or water containing traces of contaminated stools, or by eating raw contaminated pork, beef or fish (see Causes for more information).
If a tapeworm grows in your intestine, you will need treatment to get rid of it. Some adult worms grow 15-30 feet in length.
You may not know you have a tapeworm infection as it does not always cause symptoms, or symptoms may be mistaken for another illness. A tapeworm infection typically causes stomach pain and sometimes vomiting and diarrhoea (see Symptoms for more information).
Types of tapeworm
The tapeworms that most commonly infect humans include:
- the pork tapeworm (Taenia solium),
- the beef tapeworm (Taenia saginata),
- the fish tapeworm (Diphyllobothrium latum),
- the dwarf tapeworm (Hymenolepis nana), and
- the dog tapeworm (Echinococcus granulosus).
Some types of tapeworm, such as the pork tapeworm and the dog tapeworm, can cause other illnesses. This happens when tapeworm larvae (newly hatched eggs) settle in places outside a person's intestine.
How common are they?
Tapeworm infections are most commonly seen in developing countries. In the UK, tapeworm infections in people are rare, although some types are found more often than others. For example, in 2005:
- there were 71 reports of infection with the beef and pork tapeworms in England and Wales (although some may have become infected abroad), and
- there were 11 cases of hydatid disease (caused by infection with the dog tapeworm) reported in England and Wales.
Outlook
The beef tapeworm lives only in your intestines and infection with it is easily treated with tablets.
However, infection with other tapeworms or tapeworm larvae can lead to complications (see Complications page). Larvae infections are more difficult to treat because the larvae will have settled in other parts of your body outside your intestines.
