Intestinal parasites are parasites that can infect the gastro-intestinal tract of humans and other animals. They can live throughout the body, but most prefer the intestinal wall. Means of exposure include: ingestion of undercooked meat, drinking infected water, and skin absorption. The two main types of intestinal parasites are those helminths and protozoa that reside in the intestines (not all helminths and protozoa are intestinal parasites). An intestinal parasite can damage or sicken its host via an infection which is called helminthiasis in the case of helminths.