This is an incomplete list of organisms that are true parasites upon other organisms. For information on parasitoids, see main article: Parasitoid.
Endoparasites
(endo = within; parasites that live inside their hosts)
Plants
- Rafflesia
- Cuscuta
Parasitic worms
These can be categorized into three groups; cestodes, nematodes and trematodes. Examples include:
- Acanthocephala
- Ascariasis (roundworms)
- Cestoda (tapeworms) including: Taenia saginata (human beef tapeworm), Taenia solium (human pork tapeworm), Diphyllobothrium latum (fish tapeworm) and Echinococcosis (hydatid tapeworm)
- Clonorchis sinensis (the Chinese liver fluke)
- Dracunculus medinensis (Guinea worm)
- Enterobius vermicularis (pinworm)
- Filariasis
- Hookworm
- Loa loa
- Onchocerciasis (river blindness)
- Schistosomiasis
- Strongyloides stercoralis
- Tapeworm
- Toxocara canis (dog roundworm)
- Trichinella
- Whipworm
- Ring worm
Protozoans
- Entamoeba histolytica and Entamoeba coli - can cause Amoebiasis
- Acanthamoeba
- Balamuthia mandrillaris
- Giardia
- Cyclospora cayetanensis
- Cryptosporidium
- Toxoplasma gondii
- Leishmania - L. tropica, L. donovani, and L. mexicana are known to cause Leishmaniasis.
- Plasmodium - causes the fatal disease, Malaria. P. falciparum, P. vivax, and P. malariae are pathogenic to humans.
- Babesia
Fungi
- Gymnosporangium and other rusts
- Pyrenophora teres
- Cordyceps
Ectoparasites
(ecto = outside; parasites that live on but not within their hosts, for example, attached to their skin)
Arthropoda
- Acari
- Varroa destructor
- Cymothoa exigua
- Bed bugs
- Culicidae (mosquitoes)
- Hippoboscoidea
- Tsetse fly
- Lipoptena
- Melophagus ovinus, (sheep keds) and relatives
- Oestridae (bot flies)
- Human botfly
- Phthiraptera (Lice)
- Body louse
- Crab louse
- Head louse
- Siphonaptera (fleas)
- Tabanidae (horse flies)
- Tantulocarida
- Triatominae
- Pea crab
- Sacculina
Annelids
- Hirudinea (some leeches)
Monogeneans
Monogeneans are flatworms, generally ectoparasites on fish.
- Calydiscoides euzeti
- Lethacotyle vera
- Protocotyle euzetmaillardi
- Pseudorhabdosynochus spp.
Mollusks
- Cancellaria cooperii
- Glochidium
- Pyramidellidae
Chordates
- Cookiecutter shark
- Candiru (vampire fish of Brazil, a facultative parasite)
- Lampreys
- Male Deep sea anglers
- False cleanerfish
- Hood mockingbird
- Oxpeckers - Although oxpeckers mainly eat other parasites that feed on large mammals, oxpeckers have been observed to open new wounds and enhance existing ones in order to drink the blood of their perches. Oxpeckers also feed on the earwax and dandruffs of mammals, although less is known about the benefits of this to the mammal, it is suspected that this is also a parasitic behaviour. Some oxpecker hosts are intolerant of their presence. Elephants and some antelope will actively dislodge the oxpeckers when they land.
- Snubnosed eel
- Vampire bat
- Vampire finch
Plants
- Mistletoe
- Certain orchids
Fungi
- Corn smut
- Certain mushrooms