How do kids get pen worms?

Pin worms: Pin works have a human to human transmission(feco oral).The eggs are present on the anus and through person to person get ingested. The eggs are hardy and can remain viable in a moist environment for up to three weeks. Please see the graphic for the life cycle. The most common symptoms is anal itching and it is usually diagnosed by "scotch tape method" to look under the microscope.

Parasite: Infection occurs from touching the perianal area due to itching at night and swallowing the egg from clothing beddings and thumb sucking DX by looking for threadlike worms around anus at night only.

They swallow the egg: How you may ask? Well, kids tend to play in the dirt, and if that dirt gets under their fingernails, and it will, and if the dirt happens to have the pinworm eggs in the soil, when the child puts their fingers in their mouth or eats something without washing their hands, the egg (which is too small to see without magnification) gets ingested and hatches in the intestine, and out comes the pinworm.