Threadworms, also known as pinworms, are tiny parasitic worms that infect the large intestine of humans.
Threadworms are a common type of worm infection in the UK, particularly in children under the age of 10.
The worms are white and look like small pieces of thread. You may notice them around your child's bottom or in their faeces.
They don't always cause symptoms, but people often experience itchiness. It can be worse at night and disturb sleep.