Trypanosoma congolense
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Blood smear from a dog with Trypanosoma congolense |
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| Trypanosoma congolense | ||||||||||||
| Broden , 1904 |
Trypanosoma congolense is a type of unicellular parasite within the genus of the trypanosomes , whichoccurs in Africaas a pathogen of the nagana , an animal disease in ruminants . The parasite istransmittedby tsetse flies .
Discovery and Description
Trypanosoma congolense was first described in 1904 by the Belgian doctor Alphonse Broden and named after the place where it was found, the colony of the Belgian Congo .
The protozoa has a single flagellum in all cell forms , which runs on the cell surface under a relatively inconspicuous undulating membrane to the front end of the cell, but in contrast to other trypanosomes does not become a free-swinging flagellum. The cells also have a medium-sized kinetoplast, a collection of deoxyribonucleic acid within a large mitochondrion . The parasite occurs in mammals in a trypomastigote cell shape up to 18 µm long. Besides trypomastigotes, epimastigotes are also observed in insects; these differ in the position of the flagellum base relative to the beginning of the cell.
Within the genus Trypanosoma , Trypanosoma vivax is classified in the subgenus Nannomonas . Within the species, three subgroups are distinguished based on biochemical and genetic characteristics:
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Trypanosoma congolense
- "Riverine forest"
- "Savannah"
- "Kenya coast / kilifi"
The Trypanosoma congolense - "Tsavo" group is assigned to the species Trypanosoma simiae , which also belongs to the subgenus Nannomonas , according to molecular analyzes . The genetic differences within the species Trypanosoma vivax are greater than in Trypanosoma brucei or the entire subgenus Trypanozoon ; however, the current taxonomy does not reflect these differences, which would justify splitting into several species.
Distribution and host animals
Trypanosoma congolense occurs almost exclusively in Africa south of the Sahara, in the range of the tsetse flies. The parasite is the main Nagana pathogen in East Africa, while Trypanosoma vivax dominates in West Africa .
Trypanosoma congolense can infect many pets, including cattle, domestic horses, sheep, goats, camels, pigs, and dogs. Many wildlife can be reservoir hosts. The most important vector is the tsetse fly; mechanical transmission by other insects outside the tsetse area appears to play only a minor role epidemiologically, if at all.
Life cycle
Trypanosoma congolense has a complex life cycle with host changes between mammals and insects. In mammals, the trypomastigote parasite multiplies mainly in the blood, but also in intercellular tissue fluids. In tsetse flies, after ingesting parasites with a meal of blood, they multiply in both the midgut and the proboscis . Epimastigote parasites multiply in the proboscis and later transform into metacyclic trypomastigote forms which can re-infect a mammal.
literature
- Ian Maudlin, PH Holmes, Michael A. Miles (Eds.): The Trypanosomiases . CABI Publishing, Wallingford 2004, ISBN 085199475X
Individual evidence
- ↑ Steverding D. The history of African trypanosomiasis. In: Parasite Vectors. 2008 Feb 12; 1 (1): 3. PMID 18275594
- ^ A b Gibson W. Resolution of the species problem in African trypanosomes. In: Int J Parasitol. 2007 Jul; 37 (8-9): 829-38. PMID 17451719
