Worms Dr Trisha Macnair There are a number of different types of worm infection in the UK.

In this article

What are worms? Symptoms

Causes and risk factors Treatment and recovery

There are many different types of worm infection, but the most common in the UK generally cause only minor illnesses. These include:

Threadworms - also known as pinworms - are the most common parasitic worms in the UK. They're tiny (about 1cm long), pale, thin worms that look like cotton threads and thrive in the intestines.

Roundworms - also known asnematodes, are larger, some look more like garden worms and also live in the intestines. They are less common than threadworms.

Tapeworms – also known as cestode, are long ribbon-like worms that can be caught from undercooked meat and fish and contaminated water.

Other worms - tapeworms and flukes - are also occasionally problematic in the UK.

The main symptom of threadworms is itching around the anus or vulva

The main symptom of threadworms is itching around the anus or vulva. This is worse at night when the worms come to the skin surface to lay eggs. The worms may also be seen on faeces.

Round worms usually do not cause any symptoms although they the toxocara canis worm can lead to visual problems when they migrate to the eye and cause inflammation and scarring of the retina. The worms may also move to the lungs, causing a cough and asthma, and lead to swelling in other body organs.

Tapeworms may cause vague abdominal symptoms. They may become encysted in muscle, skin, heart, eye and brain.

Threadworms are usually passed on by poor hygiene. Children easily pick up threadworms from each other through contact with skin or objects contaminated with the eggs of worms. These enter the mouth and grow into adult worms in the gut. Poor hygiene, particularly not washing hands after using the toilet, is a major factor in the spread of infection.

Exposure to cat and dog faeces can cause toxocara worm infections. Pregnant women and children should steer clear of litter trays and always wash their hands after contact with pets.

Tapeworms can be caught from pets and occasionally when children accidentally swallow a dog flea infected with the worm.

Threadworms can be diagnosed by seeing the worms in or on faeces, or by collecting a sample of their eggs by pressing a small strip of sticky tape to the skin around the child's anus as soon as they wake in the morning.

Anti-parasitic drugs are used to treat threadworms, and a single dose may be all that is needed. All the family should be treated at the same time.

Toxocara worms can be diagnosed using a blood test, but need specialist investigation and treatment. Anti-parasitic drugs are used for this and other worm infections.

Careful hygiene can reduce the risk of worm infections. Pets should be wormed regularly and the garden kept clear of faeces. Children should wash their hands after playing with animals and be taught not to put soil into their mouths.

This article was last medically reviewed by Dr Orlena Kerek in March 2009