Family doctor

Overview

• A tapeworm (Taenia) is an infestation of the digestive tract with the tapeworm parasite
• A tapeworm can come from a cow, pig, sheep, dog, cat and other animals
• Tapeworm eggs are passed in the stools of a person who is infected and spread through water or surfaces contaminated with feces
• People with tapeworms can reinfect themselves
• Tapeworm eggs hatch in the intestine and develop in cysticerci (cysts) in the muscles, brain, other organs or eyes

What is it?

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.

In the case of the pork tapeworm (t.solium), eggs hatch in the stomach and the larvae travel through the stomach lining to the bloodstream and can develop into cysts in other parts of the body (e.g. brain and under the skin). This causes a disease known as cysticercosis.

One species of tapeworm (e.granulosus) usually confines itself to dogs (gut) and sheep (where the cysts can cause hydatid disease). If the eggs of this worm are ingested by humans, they can lead to hydatid cysts around the body (usually in the liver).

Infection is more common in rural areas and developing countries with poor hygiene.

What are the symptoms?

Symptoms of tapeworm infection differ according to the location of cysts formed in the body. And symptoms may not occur for months, or even years after infection. In some cases, there are no symptoms.

A tapeworm in the intestine may cause mild stomach upset or diarrhoea. In some cases segments of the tapeworm can detach and appear in feces. Other possible symptoms include unexplained weight loss, anaemia, weakness, fatigue, and malnutrition.

Cysticerci in muscles may cause no symptoms but can form lumps under the skin.

Cysts in the eyes are rare, but they can float in the eye and cause blurred vision. In rare cases an eye infection can cause detachment of the retina.

Cysticerci in the brain or spinal cord (neurocysticercosis) can cause headaches and seizures. Other less common symptoms include confusion, loss of balance, and swelling of the brain. The disease can be fatal in some cases.

Diagnosis involves taking a patient history which includes information about travel movements and eating habits. Blood tests are used to help diagnose the infection and stool specimens collected over several days may also be necessary for laboratory diagnosis.

An MRI or CT brain scan is usually required for diagnosing neurocysticercosis.

What is the treatment?

In most cases the infection is treated with anti-parasitic and anti-inflammatory drugs.

Surgery may be required for cysts in the eyes that are not cured with pharmaceutical treatment.

Some cases of tapeworm infection are not treated such as when the larvae is considered dead or when there is only one cyst.

How can they be prevented?

• Avoid eating raw or undercooked meat
• Be extra careful with handling and eating food in developing countries
• Drink only bottled or boiled water in developing countries

Getting help

Seek advice from your doctor if you suspect you have come in contact with a tapeworm or are suffering from any symptoms.