There are several types of worms that can cause problems in humans, including threadworms (also known as pinworms), roundworms, tapeworms, whipworms and hookworms. Threadworms are the only type of worm infection that is commonly seen throughout Australia.

What are the symptoms of threadworm infection?

Usually the symptoms have a sudden onset, often at night. The tell-tale signs of worms include:

  • an itchy bottom;
  • disturbed sleep;
  • irritability;
  • tiredness; and
  • lack of interest in eating.

It’s also possible to have no symptoms with a mild infection. Sometimes, worms can be seen on the outside of bowel motions or around the anus.

How do people become infected with threadworms?

The worms are caught by accidentally ingesting their eggs, which then hatch and infect the intestine. The mature worms travel to the area around the anus, where they lay their eggs (this is what causes the itchy bottom).

Infection can be through direct contact between individuals. Self re-infection is also common, and results from the microscopic eggs sticking to the fingers or lodging under the fingernails after scratching the anal area, and then being re-ingested. Also, because the eggs may survive for several weeks, infection may be through contact with contaminated objects such as clothing or bedding.

It should be noted that threadworms cannot be caught from pets.

How is a worm infection diagnosed?

If you think you or your child has worms, you should see your doctor, who may do tests to diagnose the condition and identify the type of worm involved. Your doctor may recommend a tape test to diagnose threadworms, which involves pressing a clear piece of adhesive tape against the anal skin and then examining the tape under the microscope for any eggs. If another type of worm infection is suspected, you may need to give a stool sample, so that any worms or eggs can be found and identified.

How are worms treated?

Fortunately treatment for threadworms is easy. Many anti-worm preparations, for example pyrantel (e.g. Anthel, Combantrin) and mebendazole (e.g. Vermox) can be bought over-the-counter at pharmacies, but some are only available on prescription, such as albendazole (Zentel). Some anti-worm medicines are unsuitable for pregnant women or children aged less than 12-24 months. Suspensions are available for children not old enough to take tablets. Your doctor will advise you on the most appropriate treatment for you.

Other types of worms can also usually be effectively treated with oral medications — your doctor will prescribe treatment based on the type of worm infection and your symptoms.

What can you do to help prevent re-infection with threadworms?

Doctors advise treating the whole family if one member has threadworms, even if others have no symptoms. This is because the worms spread very easily and re-infection is common. You should also take care to prevent re-infection by:

  • washing your hands thoroughly before eating food and after the toilet;
  • scrubbing underneath your fingernails and keeping them short, as eggs may lodge under the nails;
  • having a daily morning bath/shower to help wash the eggs away;
  • disinfecting the toilet seat daily for the week after treatment; and
  • washing bed linen and towels in hot water.

If children scratch themselves in their sleep, get them to wear underpants and pyjamas to bed to help prevent anus-to-mouth transfer.

When should you seek medical advice?

You should seek medical advice if:

  • you have recently returned from overseas, especially Asia or Africa;
  • there is blood in your faeces;
  • you have abdominal pain;
  • there is accompanying diarrhoea or vomiting;
  • you have experienced a large weight loss;
  • you are pregnant;
  • the skin around the anal area is broken due to scratching; or
  • the worms are in a child who is under 6 months old.

Last Reviewed: 23/11/2009



1. Worms [revised June 2006]. In: eTG complete [Internet]. Melbourne: Therapeutic Guidelines Limited; 2009 Nov. (Accessed 2009 Nov 26.)