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Gastro-intestinal system
When people refer to worms, they are usually talking about threadworms (Enterobius vermicularis), also known as pinworm. Threadworms get their name because they look like small pieces of white thread. The mature female worm can be about 10mm in length, while the mature male worm is about half this length. The worms live in the intestines as parasites, absorbing their nourishment from the person who carries them. Threadworms are not usually harmful, but they are very irritating and cause itching around the anus, particularly at night which can disturb sleep.

Threadworms are the most common type of worm infestation in the UK, estimated to affect about 20 out of every 100 people in the general community, and as many as 65 out of every 100 people living in close communities such as boarding schools and nursing homes. Adults and children can have worms, but they are more common in children. Although often a cause of embarrassment, worms are a common complaint and can affect anyone of any social status.

Roundworm (Ascaris lumbricoides) and tapeworm infestations (Taenia solium and Taenia saginata do occur in the UK but they are much rarer than threadworm infestations and are usually picked up when travelling abroad in developing countries where standards of hygiene may be poor. One rare but notorious type of roundworm from dogs (Toxocara canis) can cause a disease known as toxocariasis. It can affect the eyes, brain, lungs and liver of those who become infected by coming into contact with the eggs of the roundworm from the faeces of dogs who carry the roundworm. This is why it is critical to keep dogs away from playgrounds and other children's play areas.

As roundworm and tapeworm infestations are rare in the UK, this article will be confined to the description of threadworms.
Mature female threadworms leave the intestines, usually at night when the person is sleeping, to lay their eggs around the person's anus. As the eggs are laid, the female threadworm also deposits a sticky mucus which irritates the area. When the person scratches to relieve the itch, eggs are picked up on the fingers and beneath the finger nails. If the hands and nails are not washed properly, the eggs can be easily transferred back to the mouth and swallowed. The eggs hatch in the intestine, grow into mature adults within a few weeks, which lay more eggs to repeat the cycle.

In addition, if the person does not wash his or her hands properly after going to the toilet, the eggs are easily transferred to other people either through direct person to person contact, or indirectly through touching objects. This is why threadworm is more common in children than adults because children play closely with other children, often putting their fingers and toys in each other's mouth.

The most common symptom of threadworms is itching around the anus where the eggs are laid. In females, the area around the vagina may also itch. In a child, a reliable sign of threadworm is if the child keeps scratching his or her bottom, particularly at night. Sometimes it is possible to see the threadworms in the child's faeces or coming out of the child's bottom.

The aim of treatment is to get rid of the threadworms and prevent re-infestation. The medicines used are called anthelmintics, of which, the most widely used are piperazine and mebendazole.

Piperazine paralyses the threadworms, but does not kill them. Consequently, it is taken together with senna, a laxative that stimulates bowel movements and clears the worm from the intestine while it is paralysed. The dose should be repeated after 14 days to prevent reinfestation.

Mebendezole inhibits the threadworm's uptake of glucose from the intestines, therefore killing rather than paralysing the worm. It is considered to be more effective than piperazine and works after a single dose.

All members of the family should be treated, even if no symptoms are present. It may be advisable to repeat the treatment two weeks later to ensure that worms developing from eggs at the time of the first dose are eliminated before they develop into mature adults.

Both piperazine and mebendezole should be avoided during pregnancy as they may cause malformations in the unborn baby.

When to see your pharmacist
Do not be embarrassed to talk to your pharmacist if you think you or members of your family have threadworms. Threadworm infestations are very common and there is no social disgrace in having them.

Preparations containing either mebendezole or piperazine are available from your pharmacy without the need for a prescription. However, it is important when purchasing these products that you let the pharmacist know the ages of the people in your family, whether anybody is pregnant or breast feeding, or if anybody has any other illnesses or taking any other medications. Children under 2 years of age should not be given mebendezole. Children under 3 months of age or those with kidney disease, liver disease or epilepsy should not be given piperazine. If you are pregnant, your pharmacist will advise you to see your doctor.
When to see your doctor
If over-the-counter treatments do not seem to have got rid of the threadworms, you should see your doctor. If you are pregnant or breast-feeding and think you have worms, you should see your doctor first, as over-the-counter medicines are not suitable for you. If you have recently returned from abroad and have developed any pains in your stomach or noticed any change in your bowel habits, you should also see your doctor as you may have another type of worm infestation.
Living with worms
All members of the family should improve personal hygiene, ensuring that hands and nails are washed thoroughly every time they go to the toilet and before eating. Surfaces should be cleaned thoroughly and children should be discouraged from putting their hands in their mouth, biting their nails or sucking their thumb. Bed linen and underwear should be changed regularly and items such as flannels and towels should not be shared. Bathing or showering in the morning will help remove the eggs that have been laid overnight.
Useful Tips
  • Wear underclothes at night and change underwear daily
  • Keep finger nails short
  • Encourage thorough hand-washing, especially under the nails
  • Shower the area around the bottom daily to wash away eggs
  • Children can be made to wear cotton gloves at night to stop eggs being transferred from the bottom to the mouth


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