Pinworms

What are pinworms?

The most common type of human worm infection in Australia is pinworm. Other names for this parasite include threadworm and Enterobius vermicularis, or the common term ‘worms’.

Children are more likely to pick up an infection than an adult, probably because of children’s tendency to put their fingers in their mouths. However, once a child is infected, other members of their household are also likely to get pinworms unless strict hygiene practices are observed. Infection can happen to anyone, regardless of a child’s home hygiene.

Despite the unsavoury reputation, a pinworm infection is relatively harmless and can be easily treated.

Worms require a host in order to survive. In the case of pinworms, the human acts as the host.

Life cycle of a pinworm

Infections begin when pinworm eggs are eaten, usually directly through contaminated hands or indirectly through contaminated food, bedding, clothing or other articles. The eggs then travel to the gut where they hatch and mature. A grown pinworm is yellowish white, slender and about one centimetre long.

Around 4 weeks after ingestion, the adult female moves down the gut and exits the body via the anus to lay a batch of eggs on the surrounding skin, often at night. The worm then dies, her reproductive mission complete.

The eggs may cause intense itching, especially at night, so children can easily reinfect themselves by scratching the anus and scraping eggs under their fingernails. These eggs can then be transferred to the mouth and the whole life cycle of the pinworm starts again.

The eggs can survive on surfaces or objects (such as furniture, kitchen surfaces and toothbrushes) for up to 2 weeks in the right conditions and can infect other people if transferred to the mouth or food.

Household pets cannot be infected with pinworms or pass them on to humans.

Symptoms of pinworm

Pinworm infections often produce no symptoms but, when they occur, symptoms can include:

• itchy bottom, especially at night
• reduced appetite
• feeling mildly unwell
• inflammation of the vagina
• adult worms can sometimes be seen in the faeces, and eggs may be seen clinging to the skin around the anus
• irritability and behavioural changes.

Treatment for pinworm infection

Your doctor might want to perform a test to make sure the problem is a pinworm infection. This is done by collecting the eggs from around the anus using sticky tape first thing in the morning.

Medication is available to kill the worms and this is usually prescribed for the person who is infected and all other members of the household. One dose may be followed up with a second dose 2 weeks later to take care of any surviving worms.

Although the medication is safe for humans, you should consult your doctor or chemist before commencing treatment.

Preventing another pinworm infection

Suggestions to prevent another infection during treatment include:

• All family members should wash their hands and nails thoroughly with soap and water, particularly after going to the toilet, after changing nappies, before preparing food and before eating food.
• Discourage scratching of the bottom and nail biting.
• Keep fingernails short.
• Daily bathing and showering.
• Wash all sheets, bed linen, pyjamas and sleepwear in hot water to kill any pinworm eggs.
• Clean toilet seats and potties regularly with disinfectant (remember to store the disinfectant out of reach of children).
• All family members should take the medication, regardless of whether they are experiencing symptoms.

Where to get help

• Your GP (doctor)
• Pharmacist
• NURSE-ON-CALL Tel. 1300 606 024 – for expert health information and advice (24 hours, 7 days)
• Maternal and Child Health Line Tel. 13 22 29 (24 hours, 7 days)