Parasite
A parasite is an Organism that lives in or on the living tissue of a host organism at the expense of that host. The Biological interaction between the host and the parasite is called Parasitism. Parasitism is a type of Symbiosis, by one definition, although another definition of symbiosis excludes parasitism, since certain types of DNA, such as transposable elements and B chromosomes, may also be considered as parasites of the host Genome.
Examples
- Endoparasites (endo = within; parasites that live inside their hosts)
- Plants
- Animals
- Acanthocephala
- Candiru (Vampire fish of Brazil)
- Clonorchis sinensis (the Chinese liver fluke)
- Cymothoa exigua
- Dracunculiasis (Guinea Worm Disease)
- Enterobius vermicularis
- Strepsiptera
- Strongyloides stercoralis
- Fungi (such as Ringworm)
- Gymnosporangium and other rusts
- Protists (Protozoa)
- Malaria (a common blood disease caused by Plasmodium)
- Sleeping sickness, Chagas disease and Leishmania, caused by Kinetoplastid protists of the Trypanosoma and Leishmania genera.
- Balantidium coli (the only ciliated protozoan to infect humans)
- Giardia lamblia (the most common intestinal protozoan in the United States)
- Entamoeba histolytica (causes Amebiasis, common in developing countries)
- Ectoparasites (ecto = outside; parasites that live on but not within their hosts, for example, attached to their skin)
- Plants
- Animals
- Hirudinea (some leeches)
- Phthiraptera (Lice)
- Siphonaptera (Fleas)
- Acarina (Ticks)
- Tantulocarida
Many lifeforms are parasitic only during a part of their lifecycle. Many cuckoos, for example, are brood parasites: their young are parasitic on the host species, but adult cuckoos fend for themselves.