Enterobius vermicularis is a small nematode This common helminthic infestation has an estimated prevalence of 40 million infected individuals in the United States.
The female nematode averages 10 mm X 0.7 mm, whereas males are smaller. All socioeconomic levels are affected. Infestation often occurs in family clusters. Infestation does not equate with poor home sanitary measures (an important point when discussing therapy).