Trypanosomatid

Trypanosomes in the blood smear of a patient with African trypanosomiasis

The trypanosomatid are a group of unicellular flagellates within the group of Kinetoplastea, which are characterized by a single flagellum and live consistently as parasites. Many trypanosomatid only multiply in insects; some species undergo a change of host between insects as a vector and a vertebrate host or a plant host.

The trypanosomatid belong to the Leishmania and Trypanosoma important pathogens for leishmaniasis, Chagas disease and African trypanosomiasis in humans and for animal diseases nagana and surra. Also, some plant pests of the genus Phytomonas among the trypanosomatid.

Features

All trypanosomatid have a single flagellum, which can be reduced to the extent that they are not visible in the light microscope ( amastigote form). Furthermore, there is a single large mitochondrion a kinetoplast, a visible by staining accumulation of mitochondrial DNA. Many species show a change of form, in which the cell shape throughout the life cycle changes significantly. This is true for both the cell size as well as the position of the flagellum base ( trypomastigote, epimastigot, promastigote ) relative to the cell end.

Distribution and hosts

Representatives of the trypanosomatid are found worldwide. All species live as parasites. Some species parasitize only in a class of living creatures, mostly insects; this includes the genera Blastocrithidia, Crithidia, Herpetomonas, Leptomonas and Rhynchoidomonas. The genus Phytomonas undergoes a change of host between insects and plants as a vector, while Endotrypanum, Leishmania and Trypanosoma between insects change ( in aquatic trypanosomes also leeches ) and vertebrates.

System

The first description of an order nor under the name Trypanosomata, which was based on the type genus Trypanosoma, comes from the British marine biologist William Saville -Kent ( 1845-1908 ).

The trypanosomatid include the Neobodonida the Parabodonida and Eubodonida to Metakinetoplastina, a ribosomal RNA, defined on the basis of sequence comparisons within the group Kinetoplastea. In contrast to the other members of the trypanosomatid are exclusively parasites with only a single flagellum. Within the trypanosomatid eleven genera currently be distinguished.

  • Trypanosomatid Kent, 1880 Genus Blastocrithidia Laird, 1959
  • Crithidia Leger, 1902
  • Genus Endotrypanum Mesnil & Brimont, 1908
  • Genus Herpetomonas Kent, 1880
  • Genus Leishmania Ross, 1903
  • Genus Leptomonas Kent, 1880
  • Genus Phytomonas Donovan, 1909
  • Genus Rhynchoidomonas Patton, 1910
  • Genus Sauroleishmania Ranque, 1973
  • Genus Trypanosoma Gruby, 1843
  • Genus Wallaceina Podlipaev et al. 1,990

While the trypanosomatid itself and the genera Leishmania, Trypanosoma and Phytomonas regarded as monophyletic, the other genera are probably paraphyletic. The proliferation exclusively in insects is considered to be original; the host exchange between insects and vertebrates is probably appeared several times within the trypanosomatid.

Excavate Euglenozoa Kinetoplastid Unicellular organism Animal trypanosomiasis
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