Trypanosoma: Difference between revisions
m →External links: +Category:Protist genera |
No edit summary |
||
| Line 30: | Line 30: | ||
*''[[Trypanosoma brucei|T. brucei]]'', which causes [[African trypanosomiasis|sleeping sickness]] in humans and [[nagana]] in cattle |
*''[[Trypanosoma brucei|T. brucei]]'', which causes [[African trypanosomiasis|sleeping sickness]] in humans and [[nagana]] in cattle |
||
*''[[Trypanosoma cruzi|T. cruzi]]'', which causes [[Chagas disease]] in humans |
*''[[Trypanosoma cruzi|T. cruzi]]'', which causes [[Chagas disease]] in humans |
||
*''[[Trypanosoma congolense|T. congolense]]'', which causes [[nagana]] in |
*''[[Trypanosoma congolense|T. congolense]]'', which causes [[nagana]] in ruminant livestock, horses and a wide range if wildlife |
||
*''[[Trypanosoma equinum|T. equinum]]'', in [[South American]] horses, transmitted via [[Tabanidae]], |
*''[[Trypanosoma equinum|T. equinum]]'', in [[South American]] horses, transmitted via [[Tabanidae]], |
||
*''[[Trypanosoma equiperdum|T. equiperdum]]'', which causes [[dourine]] or [[Covering sickness]] in [[horse]]s and other [[Equidae]] |
*''[[Trypanosoma equiperdum|T. equiperdum]]'', which causes [[dourine]] or [[Covering sickness]] in [[horse]]s and other [[Equidae]] |
||
| Line 46: | Line 46: | ||
*''[[Trypanosoma rugosae|T. rugosae]]'', in amphibians |
*''[[Trypanosoma rugosae|T. rugosae]]'', in amphibians |
||
*''[[Trypanosoma sergenti|T. sergenti]]'', in amphibians |
*''[[Trypanosoma sergenti|T. sergenti]]'', in amphibians |
||
*''[[Trypanosoma simiae|T. simiae]]'', which causes [[nagana]] in |
*''[[Trypanosoma simiae|T. simiae]]'', which causes [[nagana]] in pigs. Its main reservoirs are warthogs and bush pigs |
||
*''[[Trypanosoma sinipercae|T. sinipercae]]'', in fishes |
*''[[Trypanosoma sinipercae|T. sinipercae]]'', in fishes |
||
*''[[Trypanosoma suis|T. suis]]'', which causes a different form of [[surra]] |
*''[[Trypanosoma suis|T. suis]]'', which causes a different form of [[surra]] |
||
*''[[Trypanosoma theileri|T. theileri]]'', a large trypanosome infecting ruminants |
*''[[Trypanosoma theileri|T. theileri]]'', a large trypanosome infecting ruminants |
||
*''[[Trypanosoma trigalae|T. triglae]]'', in marine [[teleost]]s |
*''[[Trypanosoma trigalae|T. triglae]]'', in marine [[teleost]]s |
||
*''[[Trypanosoma vivax|T. vivax]]'', which causes the disease [[nagana]] |
*''[[Trypanosoma vivax|T. vivax]]'', which causes the disease [[nagana]], mainly in West Africa, although it has spread to South America |
||
==Hosts and life cycle== |
==Hosts and life cycle== |
||
Revision as of 19:29, 16 December 2009
| Trypanosoma | |
|---|---|
| |
| Trypanosoma cruzi, crithidia. | |
| Scientific classification | |
| Domain: | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Order: | |
| Genus: | Trypanosoma Gruby, 1843
|
Trypanosoma is a genus of kinetoplastids (class Kinetoplastida), a monophyletic[1] group of unicellular parasitic flagellate protozoa. The name is derived from the Greek trypano (borer) and soma (body) because of their corkscrew-like motion. All trypanosomes are heteroxenous (requiring more than one obligatory host in order to complete life cycle)or are transmitted through some variation of a vector. The majority of species are transmitted by blood-feeding invertebrates but there are different mechanisms among the varying species. Trypanosomes infect a variety of hosts and cause various diseases, including the fatal disease sleeping sickness in humans. These deadly parasites mostly live in the blood and tissue fluids but can also inhabit intracellular locations in the host's body as well.
The mitochondrial genome of the Trypanosoma as well as of other kinetoplastids, known as the kinetoplast, is made up of a highly complex series of catenatated circles and minicircles and require a cohort of proteins for organisation during cell division.
Trypanosoma have evolved a strategy for avoiding a host’s immune response by implementing antigen variation. Antigen variation[2] is the process of a parasite changing its surface protein. Particularly, trypanosomes use the antigen variation of variant surface glycoprotein (VSGs). The parasite produces and covers its own plasma membrane with host VSGs. As the parasite attacks the host’s antibodies, it changes its expression to the new VSGs and masks itself from the body's natural defense mechanisms against foreign particles. This strategy allows the parasite to regularly switch to different VSGs and continue to thrive in its host. This contributes to trypanosome pathogenesis because as soon as the host's immune system responds to current VSGs, the parasite quickly switches to another type of glycoprotein.
There has been research[3] done to study the mechanism of antibody clearance from the parasite. It was found that Ig-VSG immune complexes are arranged to the posterior end where these complexes undergo Endocytosis. The researchers found the hydrodynamic flow that acts on swimming trypanosomes cause directional movement of the Ig-VSG immune complex in the plane of plasma membrane shifts to the end. The Ig-VSG complex shifts aided by hydrodynamic forces help to protect the trypanosomes against the host’s immune system.
In addition, two life cycle forms of Trypanosoma brucei are easy to culture and are genetically pliable.
Selected species
Species of Trypanosoma include the following:
- T. ambystomae in amphibians
- T. avium, which causes trypanosomiasis in birds
- T. boissoni, in elasmobranch
- T. brucei, which causes sleeping sickness in humans and nagana in cattle
- T. cruzi, which causes Chagas disease in humans
- T. congolense, which causes nagana in ruminant livestock, horses and a wide range if wildlife
- T. equinum, in South American horses, transmitted via Tabanidae,
- T. equiperdum, which causes dourine or Covering sickness in horses and other Equidae
- T. evansi, which causes one form of the disease surra in certain animals (a single case report of human infection in 2005 in India[4] was successfully treated with suramin[5])
- T. everetti, in birds
- T. hosei in amphibians
- T. levisi, in rats
- T. melophagium, in sheep, transmitted via Melophagus ovinus
- T. paddae, in birds
- T. parroti, in amphibians
- T. percae, in the fish species Perca fluviatilis
- T. rangeli, believed to be nonpathogenic to humans
- T. rotatorium, in amphibians
- T. rugosae, in amphibians
- T. sergenti, in amphibians
- T. simiae, which causes nagana in pigs. Its main reservoirs are warthogs and bush pigs
- T. sinipercae, in fishes
- T. suis, which causes a different form of surra
- T. theileri, a large trypanosome infecting ruminants
- T. triglae, in marine teleosts
- T. vivax, which causes the disease nagana, mainly in West Africa, although it has spread to South America
Hosts and life cycle
Trypanosoma undergo a complex life cycle which includes several different morphological forms. For example, Trypanosoma brucei is transmitted between mammalian hosts through a tsetse fly vector and undergoes a series of morphological and metabolic changes to adapt to these very different environments.
References
- ^ Hamilton PB, Stevens JR, Gaunt MW, Gidley J, Gibson WC (2004). "Trypanosomes are monophyletic: evidence from genes for glyceraldehyde phosphate dehydrogenase and small subunit ribosomal RNA". Int. J. Parasitol. 34 (12): 1393–404. doi:10.1016/j.ijpara.2004.08.011. PMID 15542100.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Schmidt, G.D., Roberts, L.S. Foundations of Parasitology.
{{cite book}}: Cite has empty unknown parameter:|4=(help); Text "8th ed. New York (NY)" ignored (help); Text "McGraw-Hill; 2009" ignored (help); Text "page68" ignored (help)CS1 maint: multiple names: authors list (link) - ^ Engstler M., Pfohl, T., Herminghaus, S., Boshart, M. Wiegertjes, G., Heddergott, N. and Overath,P. "Hydrodynamic Flow-Mediated Protein Sorting on the Cell Surface of Trypanosomes". Cell. 131 (3.).
{{cite journal}}: Text "Accessed 2009 Nov 25." ignored (help); Text "Available from: http://www.ncbi.nlm.nih.gov/sites/entrez." ignored (help); Text "year 2007" ignored (help)CS1 maint: multiple names: authors list (link) - ^ "A new form of human trypanosomiasis in India. Description of the first human case in the world caused by Trypanosoma evansi". Wkly. Epidemiol. Rec. 80 (7): 62–3. 2005. PMID 15771199.
- ^ Joshi PP, Chaudhari A, Shegokar VR; et al. (2006). "Treatment and follow-up of the first case of human trypanosomiasis caused by Trypanosoma evansi in India". Trans. R. Soc. Trop. Med. Hyg. 100 (10): 989–91. doi:10.1016/j.trstmh.2005.11.003. PMID 16455122.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link)
External links
- Trykipedia, Trypanosomatid specific ontologies
- Tree of Life: Trypanosoma
 | This eukaryote-related article is a stub. You can help Wikipedia by expanding it. |
 | This medical article is a stub. You can help Wikipedia by expanding it. |