This is the appearance of pinworm, Enterobiasis is prone to self-repeated infection, so it should be treated again 2-4 weeks after treatment 1 The second disease is caused by adult worms of intestinal nematodes parasitizing the cecum, appendix, colon and lower ileum. When the worms are seriously infected, they can also parasitize the upper small intestine or even the stomach and esophagus, and attach themselves to the intestinal mucosa or remain in a free state in the intestinal cavity with the help of the cephalic labial flap. Adults feed on intestinal contents, tissues or blood. After mating, the uterus of female worms is full of eggs and migrate to the lower ileum. When people sleep, some female worms migrate to the anus. Due to the change of temperature and humidity and the stimulation of oxygen outside the door, a large number of ovulated eggs are adhered to the perianal skin, and most of the females after ovulation die of dryness, but a few females can creep from the anus and return to the intestinal cavity. If they enter the vagina, uterus, fallopian tube, urethra or abdominal cavity and other parts, ectopic parasites can be the only host of pinworm, and pinworm infection is the only source of infection. There are two kinds of self-infected females at night. Occasionally crawling anus lays eggs on the surrounding skin, causing strange itching. Children scratch with their fingers and get infected with eggs. When eating or sucking, they swallow worms, hatch in the stomach and duodenum, and finally develop into adult worms in the lower small intestine and large intestine. If the nymphs hatch in the anus, the larvae can crawl into the anus and invade the large intestine, causing retrograde infection. These two ways of self-infection aggravate the infection, and the unhealed foreign infection can be infected through food toys contaminated with eggs, or by inhaling flying eggs through the nose and mouth and swallowing them. This is the main way of collective and family transmission.