Wikipedia

Trypanosoma

Trypanosoma is a genus of kinetoplastids (class Trypanosomatidae[1]), a group of unicellular parasitic flagellate protozoa under the phylum Euglenozoa.[2] The name is derived from the Ancient Greek trypano- (borer) and soma (body) because of their corkscrew-like motion. Most trypanosomes are heteroxenous (requiring more than one obligatory host to complete life cycle) and most are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. Trypanosoma equiperdum is spread between horses and other equine species by sexual contact. They are generally found in the intestine of their invertebrate host, but normally occupy the bloodstream or an intracellular environment in the vertebrate host.

Trypanosoma
Trypanosoma sp. among red blood cells.
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Discoba
Phylum: Euglenozoa
Class: Kinetoplastea
Order: Trypanosomatida
Family: Trypanosomatidae
Subfamily: Trypanosomatinae
Genus: Trypanosoma
Gruby, 1843
Subgenera
Synonyms
  • Castellanella Chalmers 1918 non Pacheco & Rodrigues 1930
  • Duttonella Chalmers 1918
  • Haematomonas Mitrophanow 1883
  • Schizotrypanum Chagas 1909
  • Trypanozoon Lühe 1906

Trypanosomes infect a variety of hosts and cause various diseases, including the fatal human diseases sleeping sickness, caused by Trypanosoma brucei,[3] and Chagas disease, caused by Trypanosoma cruzi.

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 catenated circles and minicircles and requires a cohort of proteins for organisation during cell division.

History

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In 1841, Gabriel Valentin found flagellates that today are included in Trypanoplasma in the blood of trout.[4][5]

The genus (T. sanguinis) was named by Gruby in 1843, after parasites in the blood of frogs.[6]

In 1903, David Bruce identified the protozoan parasite and the tsetse fly vector of African trypanosomiasis.[7]

Taxonomy

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Many past phylogenetic analyses using the 18S (small subunit) ribosomal RNA (SSU rRNA) sequence have indicated a non-monophyletic Trypanosoma (as "traditionally defined") with the biflagellate Bodonida nested within. These methods suggest an ancient split between a branch containing all Salivarian trypanosomes and a branch containing all non-Salivarian lineages. The latter branch in turn splits into a clade containing bird, reptilian and the Stercorarian trypanosomes infecting mammals, and a clade with a branch of fish trypanosomes and a branch of reptilian or amphibian lineages.[8][9]

However, analyses using both the combination of the glyceraldehyde phosphate dehydrogenase gene with SSU rRNA, of whole genomes, and of the kinetoplast (mitochondrial) genome indicate that Trypanosoma (again, as "traditionally defined") is, indeed, monophyletic. This is in spite of the distinctness of the clades formed by T. cruzi (cause of Chagas' disease) and T. brucei (cause of African sleeping sickness).[10][11][12][13] The division into the Salivaria and the Stercoria remains valid as each can be assigned to a clade in these analyses.[13]

Evolution

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The overall evolution of the group follows the general structure of the groups and subgenera.[13] Of interest is how the trypanosomes became parasistic in the first place, how it became dixenous (parasitizes two hosts), and how it came to affect vertebrates, mammals, and then humans in particular. The emergence of parasitism is dated back to the origin of the order Trypanosomatida, which includes both both the trypanosomes and the Leishmania; Bodo saltans is a reasonably close relative to the common ancestor of this group.[19] The emergence of a dixenous lifestyle from a monoxenous ancestor has happened at least three times, in Phytomonas, in vertebrate-infecting Trypanosoma, and in vertebrate-infecting Leishmania/Porcisia/Endotrypanum.[13]

The Salivaria split from the rest of the trypanosomes about 150 million years ago (Mya). They were probably mainly living in the guts of insects, until the appearance of tsetse flies gave them access to mammalian blood. On the other hand, the common ancestor of the T. cruzi clade (~Schizotrypanum) appeared about 84 million years ago, not long before the diversification of bats, which is thought to have contributed to the diversification of the group and ultimately a trypanosome that infects many different types of mammals.[13]

Selected species

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Species of Trypanosoma include the following:

Hosts, life cycle and morphologies

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The six main morphologies of trypanosomatids.

Two different types of trypanosomes exist, and their life cycles are different, the salivarian species and the stercorarian species.[citation needed]

Stercorarian trypanosomes infect insects, most often the triatomid kissing bug, by developing in the posterior gut followed by release into the feces and subsequent depositing on the skin of the vertebrate host. The organism then penetrates and can disseminate throughout the body. Insects become infected when taking a blood meal.[citation needed]

Salivarian trypanosomes develop in the anterior gut of insects, most importantly the Tsetse fly, and infective organisms are inoculated into the host by the insect bite before it feeds.[citation needed]

As trypanosomes progress through their life cycle they undergo a series of morphological changes as is typical of trypanosomatids. The life cycle often consists of the trypomastigote form in the vertebrate host and the trypomastigote or promastigote form in the gut of the invertebrate host. Intracellular lifecycle stages are normally found in the amastigote form. The trypomastigote morphology is unique to species in the genus Trypanosoma.[citation needed]

Meiosis

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Evidence has been obtained for meiosis in T. cruzi, and for genetic exchange.[27] T. brucei is able to undergo meiosis within the salivary glands of its tsetse fly host, and meiosis is considered to be an intrinsic part of the T. brucei developmental cycle.[28][29] An adaptive benefit of meiosis for T. crucei and T. brucei may be the recombinational repair of DNA damages that are acquired in the hostile environment of their respective hosts.[30]

References

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  1. ↑ "WHO - The parasite". WHO. Archived from the original on September 29, 2016. Retrieved 8 March 2019.
  2. ↑ "Taxonomy of African Trypanosoma species". msu.edu. Retrieved 2019-03-28.
  3. ↑ Büscher, Philippe; Cecchi, Giuliano; Jamonneau, Vincent; Priotto, Gerardo (2017). "Human African trypanosomiasis". The Lancet. 390 (10110): 2397–2409. doi:10.1016/s0140-6736(17)31510-6. ISSN 0140-6736.
  4. ↑ Leadbeater, B.S.C & McCready, S.M.M. (2000). The Flagellates. Unity, diversity and evolution. Ed.: Barry S. C. Leadbeater and J. C. Green Taylor and Francis, London, p. 12.
  5. ↑ Valentin, G. (Gabriel) (1841). Ueber ein Entozoon im Blute von Salmo fario. Wellcome Library.{{cite book}}: CS1 maint: date and year (link)
  6. ↑ Gruby, D. 1843. Recherches et observations sur une nouvelle espéce d'haematozoaire, Trypanosoma sanguinis. Comptes Rendus de l'Académie des Sciences, 17: 1134–1136, .
  7. ↑ Ellis, H. (March 2006). "Sir David Bruce, a pioneer of tropical medicine". British Journal of Hospital Medicine. 67 (3): 158. doi:10.12968/hmed.2006.67.3.20624. PMID 16562450.
  8. ↑ The molecular phylogeny of trypanosomes: evidence for an early divergence of the Salivaria. Jochen Haag, Colm O'hUigin and Peter Overath, Molecular and Biochemical Parasitology, 1 March 1998, Volume 91, Issue 1, Pages 37–49, doi:10.1016/S0166-6851(97)00185-0
  9. ↑ Environmental kinetoplastid-like 18S rRNA sequences and phylogenetic relationships among Trypanosomatidae: Paraphyly of the genus Trypanosoma. Helen Piontkivska and Austin L. Hughes, Molecular and Biochemical Parasitology, November 2005, Volume 144, Issue 1, Pages 94–99, doi:10.1016/j.molbiopara.2005.08.007
  10. ↑ 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.
  11. ↑ Leonard, G; Soanes, DM; Stevens, JR (July 2011). "Resolving the question of trypanosome monophyly: a comparative genomics approach using whole genome data sets with low taxon sampling". Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases. 11 (5): 955–9. doi:10.1016/j.meegid.2011.03.005. PMID 21419879.
  12. ↑ Deschamps, P.; Lara, E.; Marande, W.; Lopez-Garcia, P.; Ekelund, F.; Moreira, D. (1 January 2011). "Phylogenomic Analysis of Kinetoplastids Supports That Trypanosomatids Arose from within Bodonids". Molecular Biology and Evolution. 28 (1): 53–58. doi:10.1093/molbev/msq289.
  13. 1 2 3 4 5 6 Kaufer, A; Stark, D; Ellis, J (18 September 2019). "Evolutionary Insight into the Trypanosomatidae Using Alignment-Free Phylogenomics of the Kinetoplast". Pathogens (Basel, Switzerland). 8 (3). doi:10.3390/pathogens8030157. PMID 31540520.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  14. ↑ "salivarian". Retrieved 8 March 2019 – via The Free Dictionary.
  15. ↑ Sex and evolution in trypanosomes. Wendy Gibson, International Journal for Parasitology, 1 May 2001, Volume 31, Issues 5–6, Pages 643–647, doi:10.1016/S0020-7519(01)00138-2
  16. 1 2 Dihydrofolate reductases within the genus Trypanosoma. J.J. Jaffe, J.J. McCormack Jr and W.E. Gutteridge, Experimental Parasitology, 1969, Volume 25, Pages 311–318, doi:10.1016/0014-4894(69)90076-9
  17. ↑ Prevention, CDC-Centers for Disease Control and (2 May 2017). "CDC - Chagas Disease - General Information". www.cdc.gov. Retrieved 8 March 2019.
  18. ↑ Soomro, Samiullah; Tuangpermsub, Siwaporn; Ngamprasertwong, Thongchai; Kaewthamasorn, Morakot (26 July 2025). "A comprehensive genetic and phylogenetic study of Trypanosoma spp. in bats and sand flies from shared habitats in Thailand". Parasites & Vectors. 18 (1). doi:10.1186/s13071-025-06934-5.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  19. ↑ Jackson, AP; Otto, TD; Aslett, M; Armstrong, SD; Bringaud, F; Schlacht, A; Hartley, C; Sanders, M; Wastling, JM; Dacks, JB; Acosta-Serrano, A; Field, MC; Ginger, ML; Berriman, M (25 January 2016). "Kinetoplastid Phylogenomics Reveals the Evolutionary Innovations Associated with the Origins of Parasitism". Current biology : CB. 26 (2): 161–172. doi:10.1016/j.cub.2015.11.055. PMID 26725202.
  20. ↑ Carnes J, Anupama A, Balmer O, Jackson A, Lewis M, Brown R, Cestari I, Desquesnes M, Gendrin C, Hertz-Fowler C, Imamura H, Ivens A, Kořený L, Lai DH, MacLeod A, McDermott SM, Merritt C, Monnerat S, Moon W, Myler P, Phan I, Ramasamy G, Sivam D, Lun ZR, Lukeš J, Stuart K, Schnaufer A (2015) Genome and phylogenetic analyses of Trypanosoma evansi reveal extensive similarity to T. brucei and multiple independent origins for dyskinetoplasty. PLoS Negl Trop Dis 9(1):e3404. doi: 10.1371/journal.pntd.0003404
  21. 1 2 Cuypers B, Van den Broeck F, Van Reet N, Meehan CJ, Cauchard J, Wilkes JM, Claes F, Goddeeris B, Birhanu H, Dujardin JC, Laukens K, Büscher P, Deborggraeve S (2017) Genome-wide SNP analysis reveals distinct origins of Trypanosoma evansi and Trypanosoma equiperdum. Genome Biol Evol doi: 10.1093/gbe/evx102
  22. ↑ Sazmand, Alireza; Joachim, Anja (2017). "Parasitic diseases of camels in Iran (1931–2017) – a literature review". Parasite. 24. EDP Sciences: 1–15. doi:10.1051/parasite/2017024. ISSN 1776-1042. PMC 5479402. PMID 28617666. S2CID 13783061. Article Number 21. p. 2
  23. ↑ World Health, Organization (2005). "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. PMID 15771199.
  24. ↑ 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.
  25. ↑ Bernal XE, Pinto CM (2016), "Sexual differences in prevalence of a new species of trypanosome infecting túngara frogs", Int J Parasitol Parasites Wildl, 5 (1): 40–47, Bibcode:2016IJPPW...5...40B, doi:10.1016/j.ijppaw.2016.01.005, PMC 4781969, PMID 26977404
  26. ↑ Batista JS, Rodrigues CM, García HA, Bezerra FS, Olinda RG, Teixeira MM, Soto-Blanco B (2011). "Association of Trypanosoma vivax in extracellular sites with central nervous system lesions and changes in cerebrospinal fluid in experimentally infected goats". Veterinary Research. 42 (63): 1–7. doi:10.1186/1297-9716-42-63. PMC 3105954. PMID 21569364.
  27. ↑ Messenger LA, Miles MA (2015). "Evidence and importance of genetic exchange among field populations of Trypanosoma cruzi". Acta Trop. 151: 150–5. doi:10.1016/j.actatropica.2015.05.007. PMC 4644990. PMID 26188331.
  28. ↑ Peacock L, Ferris V, Sharma R, Sunter J, Bailey M, Carrington M, Gibson W (2011). "Identification of the meiotic life cycle stage of Trypanosoma brucei in the tsetse fly" (PDF). Proc. Natl. Acad. Sci. U.S.A. 108 (9): 3671–6. Bibcode:2011PNAS..108.3671P. doi:10.1073/pnas.1019423108. PMC 3048101. PMID 21321215.
  29. ↑ Gibson W (2015). "Liaisons dangereuses: sexual recombination among pathogenic trypanosomes". Res. Microbiol. 166 (6): 459–66. doi:10.1016/j.resmic.2015.05.005. hdl:1983/1ecb5cba-da25-4e93-a3cb-b00a0477cb23. PMID 26027775. S2CID 9594154.
  30. ↑ Bernstein H, Bernstein C, Michod RE (2018). Sex in microbial pathogens. Infection, Genetics and Evolution volume 57, pages 8-25. https://doi.org/10.1016/j.meegid.2017.10.024
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