Parasitology is the study of parasites and as such that does not include bacterial, fungal or viral parasites. Human parasites are separated into intestinal and blood borne parasites. For a parasite to be defined as intestinal it must have an intestinal life cycle stage, though it may have life-cycle stages in the heart, blood vessels, and lungs in the humans, other animals or the environment.When an animal lives on another organism from which it receives food and shelter without any compensation to it, and then this association is called parasitism. The animal, which enjoys advantages, is...