Small intestine
It is approximately 1.5 cm in diameter in newborns after 35 weeks of gestational age, and 2.5–3 cm (1 inch) in diameter in adults. On abdominal X-rays, the small intestine is considered to be abnormally dilated when the diameter exceeds 3 cm. On CT scans, a diameter of over 2.5 cm is considered abnormally dilated. The surface area of the human small intestinal mucosa, due to enlargement caused by folds, villi and microvilli, averages 30 square meters.
Gastrodiscoides
Humans are now considered as the accidental host because humans are not the primary requirement for the life cycle; pigs are recognised as the principal definitive host. Infection causes a helminthic disease called gastrodiscoidiasis. It is a digenetic trematode with a complex life cycle involving asexual reproduction in an intermediate host, presumably aquatic snails, and sexual reproduction in the vertebrate host. As a hermaphrodite, eggs are produced by self-fertilisation and are released along the fæces of the host. Eggs measure ~146 by 66 μm, are rhomboidal in shape, transparent, and green in colour. Each egg contains about 24 vitelline cells and a central unembryonated ovum. Eggs in a wet environment hatch into miracidia in 9–14 days.