The eggs stay in the upper part of the intestine until they hatch. After they hatch, the worms move down the length of the intestine, trying to get out to lay eggs. When the children scratch their itchy bottoms, the tiny eggs can get under their fingernails. As the children move around the house, the eggs may be spread, and other family members may become infected. Sometimes adults breathe in the eggs when the bed covers are shaken.
Children easily infect each other while they are playing.
Pets do not spread pinworms, although they may carry their own kinds of worms. Because pinworms usually crawl out of the anus while a child sleeps, the tape test is an easy way to find pinworms. To do the tape test, your doctor will give you a tongue depressor with a piece of clear tape on it. Then the tape is placed sticky-side down on a glass slide. It is best to do this test right after your child wakes up in the morning, before moving around or washing.