Trypanosoma equiperdum

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Trypanosoma equiperdum
Trypanosoma (248 09) Trypanosoma equiperdum.jpg

Trypanosoma equiperdum

Systematics
without rank: Euglenozoa
without rank: Kinetoplastea
without rank: Metakinetoplastina
without rank: Trypanosomatida
Genre : Trypanosomes ( Trypanosoma )
Type : Trypanosoma equiperdum
Scientific name
Trypanosoma equiperdum
Doflein , 1901

Trypanosoma equiperdum is a type of unicellular parasite from the genus of the trypanosomes , which occurs as a pathogen causing the malaise , a cover disease in horses . In contrast to all other pathogenic trypanosomes, the parasite is not transmitted by insects, but almost exclusively during mating .

Discovery and Description

The first description of trypanosomes in the blood of a horse suffering from the sore disease comes from the year 1896 by J. Rouget, a doctor at the military hospital in Algiers. Of Franz Theodor Doflein the pathogen was Trypanosoma equiperdum called; the epithet equiperdum is made up of the Latin words equus (horse) and perdere (to spoil).

The unicellular organism has a single flagellum , which runs on the cell surface under an undulating membrane to the front end of the cell and becomes a free-floating flagellate there. The cells also have a small kinetoplast, a collection of deoxyribonucleic acid within a large mitochondrion ; this can be absent in some isolates. The parasite only occurs in a trypomastigote cell form. The parasite cannot be distinguished microscopically from Trypanosoma brucei or Trypanosoma evansi .

Trypanosoma equiperdum is classified in the subgenus Trypanozoon . All representatives of this subgenus, which in addition to Trypanosoma equiperdum also include Trypanosoma evansi and Trypanosoma brucei , are very similar not only microscopically but also in terms of their molecular properties. Trypanosoma equiperdum different from Trypanosoma brucei practically only by partial absence of kDNA- Maxi Circles , which occur in the kinetoplasts many copies of mitochondrial DNA . Deletions in the mitochondrial DNA mean that Trypanosoma equiperdum cannot reproduce in tsetse flies , since genes encoded by the mitochondrial DNA are essential for the oxidative energy metabolism , which is required by trypanosomes for reproduction in tsetse flies. In mammals, trypanosomes are limited to glycolysis for energy production.

Detailed molecular investigations came to the conclusion that Trypanosoma equiperdum is not monophyletic , but rather represents a group of multiple spontaneous mutations of Trypanosoma brucei ; from this it was deduced that classification as a separate species was not justified. It has been proposed to classify the parasites as a subspecies of Trypanosoma brucei with the designation Trypanosoma brucei equiperdum .

Distribution and host animals

The parasite was originally found in horses around the world. Today it is considered extinguished in Central Europe, North America and Australia. In recent years, diseases from Botswana, Ethiopia, Kyrgyzstan, Namibia, Pakistan, Russia and South Africa have repeatedly been reported to the World Organization for Animal Health . The only natural hosts are horses, mules, and donkeys. Dogs, rabbits and rodents can be infected experimentally.

Life cycle

Trypanosoma equiperdum has the simplest life cycle of all trypanosomes. Reproduction takes place exclusively in mammals, there is no change in shape as with other trypanosomes. The transmission takes place from horse to horse during the mating act. However, there are also indications of transmission from the mare to the foal. After mating, the parasites multiply in the tissues of the urinary and reproductive system, but from there they also temporarily enter the bloodstream. The number of parasites in the blood is low compared to other trypanosomes, which makes parasite detection extremely difficult.

Individual evidence

  1. ↑ J. Rouget: Contribution al'étude you trypanosome of mammifères In: Annales de l'institut Pasteur. Vol. 10. 1896, pp. 716–728 (online)
  2. ↑ Franz Theodor Doflein: The protozoa presented as parasites and pathogens from a biological point of view. Jena: Gustav Fischer, 1901, pp. 66–68 (online)
  3. ↑ A. Schnaufer, GJ Domingo, K. Stuart: Natural and induced dyskinetoplastic trypanosomatids: how to live without mitochondrial DNA. In: Int J Parasitol. 32 (9), 2002 Aug, pp. 1071-1084. PMID 12117490
  4. ↑ DH Lai, H. Hashimi, ZR Lun, FJ Ayala, J. Lukes: Adaptations of Trypanosoma brucei to gradual loss of kinetoplast DNA: Trypanosoma equiperdum and Trypanosoma evansi are petite mutants of T. brucei. In: Proc Natl Acad Sci US A. 105 (6), 2008 Feb 12, pp. 1999-2004. PMID 18245376
  5. ↑ Maling disease at the World Organization for Animal Health

literature

  • Ian Maudlin, PH Holmes, Michael A. Miles (Eds.): The Trypanosomiases . CABI Publishing, Wallingford 2004, ISBN 0-85199-475-X .
  • R. Brun, H. Hecker, ZR Lun: Trypanosoma evansi and T. equiperdum: distribution, biology, treatment and phylogenetic relationship (a review). In: Vet Parasitol. 79 (2), 1998 Oct, pp. 95-107. PMID 9806490
  • F. Claes, P. Büscher, L. Touratier, BM Goddeeris: Trypanosoma equiperdum: master of disguise or historical mistake? In: Trends Parasitol. 21 (7), 2005 Jul, pp. 316-321. PMID 15923142