Roundworms

What are roundworms?

Human roundworms (Ascariasis) is an infection caused by a worm called Ascaris lumbricoides. This worm mainly infects the intestines (guts), but other parts of the body can be affected.

Roundworms occur mostly in moist, warm, tropical countries. Children are more commonly affected than adults. Travellers to areas where it is common may become infected.

The life of a roundworm

An adult worm is about the same size and shape as a common earthworm. If you have worms in your gut, the female worm lays many tiny eggs. You pass these out with the stools (motions or faeces). Soil and water supplies may become contaminated with eggs in areas of poor sanitation.

The eggs may survive for years in moist soil. In the soil the eggs develop into larvae (tiny young worms). Larvae can get into human guts if you eat them with contaminated food. They are tiny and pass into the blood stream and are carried to the lungs.

In the lungs, the larvae develop further to about the size of a pinhead. The larvae then travel up the airways to the back of the mouth and are swallowed with saliva. These more developed larvae then grow in the guts into adult worms. An adult worm can live up to two years and lay many eggs. It then dies and is passed out with the stools.

In areas where roundworms are common, children can be continuously infected. As some worms die and are passed out in the stools, others may be growing to take their place.

What are the symptoms of roundworms?

• Many affected people have no symptoms.
• Heavy roundworm infection in children can cause nutritional problems resulting in poor growth and poor general wellbeing.
• Some affected people may develop one or more of the following:
  • high temperature (fever)
  • tiredness
  • allergic rash (urticaria)
  • abdominal (tummy) pains
  • feeling sick, vomiting and/or diarrhoea
  • nerve problems
• The larvae in the lungs can sometimes cause symptoms such as wheeze, cough, and other chest problems.
• Occasionally, roundworms cause a severe illness. For example, large numbers of worms can cause a blockage in the intestines. In some people roundworms cause serious infections to the liver or pancreas, or serious allergy symptoms.

What is the treatment for roundworms?

Treatments are usually easy and work well. The medicines kill or paralyse the worms which are then passed out of the guts with the stools.

• Mebendazole is the usual medicine used for children aged over one year, and for adults who are not pregnant or breastfeeding. It comes as a tablet or drink. You take a dose twice a day for three days. (Note: mebendazole is recommended in UK guidelines for treatment from the age of one year. However, strictly speaking, it is not licensed for use in children younger than two years of age).
• Piperazine is an alternative. This comes in a sachet and is added to a drink. A single large dose is taken. Children from three months onwards can take piperazine, but it should not be taken if you have epilepsy or liver disease.
• Other medicines such as albendazole, levamisole, and ivermectin are used in countries where roundworms are common. They are not often used in the UK unless under the advice of a specialist.
• For pregnant or breast feeding women and new-born babies - your doctor will advise.

Can roundworms be prevented?

Hygiene

In countries where roundworms are common, roundworms may be prevented by eating only cooked food and by avoiding green vegetables and salads. It is best if children do not play in areas of poor sanitation, or where human faeces is used as fertiliser. Always wash hands before eating or preparing food, and after going to the toilet or changing nappies.

Medication

If there is a high risk of infection, piperazine may be advised as a regular treatment once a month for up to three months. For example, if you stay in an area known to be contaminated, or if you travel abroad to 'at risk' areas.