Ascaris lumbricoides What Is Ascaris lumbricoides? Ascaris lumbricoides — commonly known as the human roundworm — is a large intestinal nematode parasite that inhabits the small intestine. It belongs to the family Ascarididae and is closely related to roundworms found in pigs. These worms are among the largest intestinal paras/tes affecting humans, with females reaching up to 35–40 cm in length. A defining feature is their mouth, which contains three prominent lips. What Is A
