Enterobius vermicularis, also known as vermicular intestinal nematodes, looks like a white line and is about 2 cm long. It lives in children's large intestine and is sometimes excreted with children's feces. Enterobius vermicularis adults are usually parasitic in the cecum, colon, ileum, appendix and lower rectum of human body. Enterobius vermicularis is a common parasite in human intestine, and it can also be found in other vertebrates. Its life cycle is generally15 ~ 43 days.

Enterobiasis is widely distributed all over the world, and it is a common parasitic disease among children. It is often spread in groups where children live in primary schools, families and kindergartens.

Prevalence and control of pinworm;

1, pinworm is distributed worldwide, and its infection rate is closely related to the social and economic development of various countries or regions. That is to say, pinworm is common even in developed countries, and the distribution law of infection rate is generally: urban is higher than rural, and people of all ages may be infected, but the infection rate is higher in children aged 5-7.

2. The infection of pinworm is mainly spread among young children and children. The symptoms of infected children are itching in the anus and around the anus. Children or young children may scratch the itchy parts because of itching, and at the same time they will be infected with pinworm eggs, and then spread the eggs into the children's lives by touching various seats, toys or door handles, which makes other children infected.

Effective preventive measures: children are strictly forbidden to wear open-backed pants in kindergartens or other children's playgrounds. After children play, they should insist on washing their hands, and teachers and other staff should disinfect the playgrounds in time.

3. Children's collective institutions and families are clustered locally. The distribution of pinworm has the characteristics of children's collective institutions and families. The life cycle of pinworm is relatively simple, the eggs develop very rapidly, and the eggs have strong resistance during infection, so pinworm disease is widespread. Incomplete statistics show that the average infection rate of China population is 26.36%, and it is as high as 79.83% in some areas. In these cases, there are generally dozens of pinworms parasitic in the body, and the number of severely infected people can be as high as 5000 to 10000, and patients and carriers are the only sources of infection.