A parasite is a plant or an animal that lives on, or with, or inside a larger species extracting nutrients. In some cases, the parasite can harm the host and in other situations, it is completely harmless. There are three types of parasites namely ectoparasites, endoparasites and mesoparasites.
Ectoparasites include parasites that survive outside the host and induce itching and rashes in that area. Endoparasites include parasites that survive inside the body of the host, usually in bloodstreams, muscles, digestive system and so on. Mesoparasites include parasites that enter the host through an opening of the body and embeds themselves partially on the host.
Parasitic infections can be caused by a wide variety of organisms – from protozoa, and helminths to arthropods. For instance, giardia is an intestinal infection caused by the giardia parasite.