Threadworms, also known as pinworms, are tiny, white parasitic worms that infect the large intestine of humans. Pinworms are thin and white, measuring about 1/4 to 1/2 inch (about 5 to 13 millimeters) in length.
Threadworms are a common type of worm infection in the UK, particularly in children under the age of 10.
While the infected person sleeps, female pinworms lay thousands of eggs in the folds of skin surrounding the anus. Most people infected with pinworms have no symptoms, but some people experience anal itching and restless sleep.
How threadworms are spread
Threadworms lay their eggs around an infected person’s anus (bottom), usually at night. Along with the eggs, the worm also secretes a mucus that causes itching.
If the eggs get stuck on the person’s fingertips when they scratch, they can be transferred to their mouth or on to surfaces and clothes. If other people touch an infected surface, they can then transfer the eggs to their mouth.
It’s not always possible to prevent a threadworm infection, but you can significantly reduce your risk by always maintaining good hygiene and encouraging children to do the same.
Children should wash their hands regularly, particularly after going to the toilet and before mealtimes. Kitchen and bathroom surfaces should be kept clean.
If your child is infected, encouraging them not to scratch the affected area around their anus or vagina will help prevent reinfection and reduce the risk of the infection spreading to others.