Helminth Taxonomy

Medically Important Parasitic Diseases - Lifecycles

     WHO Training Manual on Diagnosis of Intestinal Parasites
   Medically important Helminths    
  Medically important Protozoa     

There is no real consensus on the taxonomy of the helminths, differing textbooks showing different  groupings, particularly with the nematodes. The term 'Helminth' itself contains a number of phyla, many of which are completely unrelated (for example the Annelids are much more closely related to the Arthropods than the Platyhelminths, and the Nematodes appear to be even more distantly related). However, for convenience sake the term is still used to describe four groups with superficial similarities, the phyla Annelida (Trematodes), Platyhelminths (Digeneans and Cestodes), Nematoda and Acanthocephala. A fifth group, the phylum Pentastomida (the Tongue worms) are not usually included here, but a very brief description of them is given at the end of this page, as some older authorities do include them with the helminths. The following taxonomy of the Helminths is that generally used, and is shown with particular reference to the schistosomes. The two most important phyla in terms of parasites infecting man are the Platyhelminths, and the Nematodes.

For more information of the true phylogenetic relationship between these organisms, see the University of Arizona's 'Tree of Life' pages, or the University of California Museum of Paleontology Phylogeny Pages.
 

Click on the species name to see an image.

• Class Turbellaria
  • Order Neorhabdocoela
    • Temnocephala sp.
• Class Monogenea (the monogenetic trematodes)
  • Subclass Monopisthocotylea
    • Gyrodactylus sp.
    • Tetraonchus sp.
  • Subclass Polyopisthocotylea
    • Microcotyle sp.
    • Octomacrum sp.
    • Polystoma sp.
    • Polystomoides sp.
    • Rajonchocotyle sp.
• Class Trematoda
  • Subclass Aspidogastrea
    • Aspidogaster sp.
    • Cotylaspis sp.
  • Subclass Digenea (the digenetic trematodes)
    • Order Paramphistomiformes
      • Family Microscaphidiidae
        • Dictyangium sp.
      • Family Notocotylidae
        • Notocotylus notocotylus
      • Family Paramphistomidae
        • Megalodiscus temperatus
        • Watsonius sp.
        • Zygocotyle lunata
    • Order Hemiuriformes
      • Family Azygiidae
        • Proterometra sp.
    • Order Echinostomatiformes
      • Family Echinostomatidae
        • Echinostoma sp.
      • Family Fasciolidea
        • Fasciola hepatica (sheep liver fluke)
        • Fascioloides magna (giant liver fluke)
        • Fasciolopsis buski (giant intestinal fluke)
      • Family Rhopaliasidae
        • Rhopalias sp.
    • Order Strigeiformes
      • Family Brachylaemidae
        • Leucochloridium sp.
        • Postharmostomum helicis
        • Urogonimus dryobatae
      • Family Bucephalidae
        • Rhipidocotyle sp.
      • Family Diplostomatidae
        • Diplostomulum sp.
        • Uvulifer ambloplitis ("black spot" in fish)
      • Family Strigeidae
        • Cotylurus sp.
      • Family Schistosomatidae (the schistosomes or blood flukes)
        • Schistosoma sp.
    • Order Opisthorchiformes
      • Family Cryptogonimidae
        • Acetodextra sp.
        • Allochanthochasmus sp.
      • Family Opisthorchiidae
        • Clonorchis sinensis (the oriental or Chinese liver fluke)
        • Metorchis conjunctus (North American liver fluke)
      • Family Heterophyidae
        • Apophallus sp.
        • Heterophyes heterophyes (intestinal fluke)
        • Metagonimus yokogawai (the smallest human intestinal fluke)
    • Order Lepocreadiiformes
      • Family Lepocreadiidae
        • Apocreadium sp.
    • Order Plagiorchiformes
      • Suborder Plagiorchiata
        • Family Allocreadiidae
          • Allocreadium sp.
          • Crepidostomum sp.
        • Family Auridistomidae
          • Auridistomum sp.
        • Family Cephalogonimidae
          • Cephalogonimus sp.
        • Family Dicrocoeliidae
          • Conspicuum sp.
          • Dicrocoelium dendriticum (the lancet fluke)
          • Lutztrema sp.
          • Platynostomum sp.
          • Zonorchis sp.
        • Family Haematoloechidae
          • Haematoloechus medioplexus (frog lung fluke)
        • Family Lecithodendriidae
          • Loxogenes sp.
          • Parabascus sp.
        • Family Lissorchiidae
          • Lissorchis fairporti
          • Triganodistomum sp.
        • Family Macroderoididae
          • Alloglossidium corti
        • Family Microphallidae
          • Microphallus sp.
        • Family Plagiorchiidae
          • Styphlodora sp.
        • Family Pleorchiidae
          • Pleorchis sp.
        • Family Prosthogonimidae
          • Prosthogonimus macrorchis
        • Family Telorchiidae
          • Telorchis sp.
      • Suborder Troglotremata
        • Family Troglotrematidae
          • Paragonimus westermani (human lung fluke)
• Class Cestoidea
  • Subclass Cestodaria
    • Gyrocotyle sp.
  • Subclass Eucestoda (the tapeworms)
    • Order Caryophyllidea
      • Glaridacris catastomus
    • Order Cyclophyllidea
      • Choanotaenia sp.
      • Dipylidium caninum (cucumber tapeworm)
      • Echinococcus granulosus
      • Echinococcus multilocularis
      • Hymenolepis spp.
      • Hymenolepis diminuta
      • Hymenolepis (Vampirolepis) nana (dwarf tapeworm)
      • Mesocestoides sp.
      • Moniezia expansa
      • Multiceps serialis
      • Taenia spp. (pork and beef tapeworms of humans)
      • Taenia pisiformis (canine tapeworm)
      • Taenia serialis
    • Order Proteocephalata
      • Corallobothrium sp.
      • Ophiotaenia sp.
      • Proteocephalus sp.
    • Order Pseudophyllidea
      • Bothriocephalus sp.
    • Diplogonoporus grandis
    • Diphyllobothrium latum (broad fish tapeworm)
    • Haplobothrium sp.
    • Ligula intestinalis
    • Triaenophorus crassus
    • Order Tetraphyllidea
    • Order Trypanorhyncha

• Class Aphasmida (=Enoplea)
  • Order Dioctophymatida
    • Family Dioctophymatidae
      • Dioctophyme renale
    • Family Eustrongylidae
      • Eustrongylides tubifex
  • Order Trichurida
    • Family Capillaridae
      • Capillaria hepatica
      • Capillaria philippinensis
    • Family Trichinellidae
      • Trichinella spiralis (trichinosis, trichinellosis)
    • Family Trichuridae
      • Trichuris spp. (whipworms)
• Class Rhabditae
  • Order Rhabditidae
    • Strongyloides stercoralis
  • Order Strongylida
    • Family Ancylostomidae
      • Ancylostoma spp. (hookworms)
      • Necator americanus (hookworms)
      • Placoconus (= Arthrocephalus) sp.
    • Family Angiostrongylidae
      • Angiostrongylus cantonensis
    • Family Trichostongyloidae
      • Cooperia spp.
      • Haemonchus spp.
      • Nematodirus spp.
      • Obeliscoides cuniculi
      • Ostertagia spp.
      • Trichostongylus spp.
  • Order Ascaridida
    • Ascaris spp. (human and pig roundworms)
    • Toxocara canis (canine roundworms)
    • Baylisascaris procyonis
    • Anisakis spp.
  • Order Oxyurida
    • Enterobius vermicularis (pinworms)
    • Cosmocerella sp.
  • Order Spirurida
    • Suborder Spirurina
      • Family Onchocercidae
        • Brugia malayi (brugian filariasis, elephantiasis)
        • Dirofilaria immitis (canine heartworm)
        • Loa loa (African eye worm)
        • Onchocerca volvulus (onchocerciasis, river blindness)
        • Wuchereria bancrofti (bancroftian filariasis, elephantiasis)
      • Family Rhabdochonidae
        • Spinitectus sp.
    • Suborder Camallanina
      • Family Camallanidae
        • Camallanus oxycephalus
      • Family Dracunculidae
        • Dracunculus medinensis (guinea worm, fiery serpent)
        • Philometra cylindracea

• Class Archiacanthocephala
  • Macrocanthorhynchus hirudinaceus
  • Moniliformis sp.
• Class Palaeacanthocephala
  • Order Echinorhynchida
    • Leptorhynchoides sp.
    • Pomphorhynchus sp.
    • Echinorhynchus sp.
  • Order Polymorphida
    • Plagiorhynchus sp.
    • Polymorphus minutus

• Class Hirudinea (leeches)
  • Order Rhynchobdellida
    • Family Glossiphoniidae
      • Placobdella sp.