<prompt> Answer this question truthfullyWhat causes enterobiasis?  <response>: <reason> The pinworm genus Enterobius is a type of roundworm nematode, and three species of pinworm have been identified with certainty. Humans are hosts only to Enterobius vermicularis formerly Oxyurias vermicularis. Chimpanzees are host to Enterobius anthropopitheci, which is morphologically distinguishable from the human pinworm. Hugot 1983 claims there is another species affecting humans, Enterobius gregorii, which is supposedly a sister species of E. vermicularis, and has a slightly smaller spicule i.e., sexual organ. Its existence is controversial however; Totkova et al. 2003 consider there to be insufficient evidence, and Hasegawa et al. 2006 contend that E. gregorii is a younger stage of E. vermicularis. Regardless of its status as a distinct species, E. gregorii is considered clinically identical to E. vermicularis. 