Trypanosoma

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Trypanosoma
Trypanosoma sp. PHIL 613 lores.jpg
Trypanosoma sp. among red blood cells.
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Phylum: Euglenozoa
Class: Kinetoplastea
Order: Trypanosomatida
Family: Trypanosomatidae
Genus: Trypanosoma
Gruby, 1843
Subgenera
Synonyms
  • CastellanellaChalmers 1918 non Pacheco & Rodrigues 1930
  • DuttonellaChalmers 1918
  • HaematomonasMitrophanow 1883
  • SchizotrypanumChagas 1909
  • TrypanozoonLühe 1906

Trypanosoma is a genus of kinetoplastids (class Trypanosomatidae [1] ), a monophyletic [2] group of unicellular parasitic flagellate protozoa. Trypanosoma is part of the phylum Euglenozoa. [3] The name is derived from the 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.

Contents

Trypanosomes infect a variety of hosts and cause various diseases, including the fatal human diseases sleeping sickness, caused by Trypanosoma brucei , [4] 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

In 1841, Gabriel Valentin found flagellates that today are included in Trypanoplasma in the blood of trout. [5] [6]

The genus (T. sanguinis) was named by Gruby in 1843, after parasites in the blood of frogs. [7]

In 1903, David Bruce identified the protozoan parasite and the tsetse fly vector of African trypanosomiasis. [8]

Taxonomy

A number of different methods demonstrate that the traditional Trypanosoma genus is not monophyletic, with the biflagellate Bodonida nested within. The American and African trypanosomes constitute distinct clades, implying that the major human disease agents T. cruzi (cause of Chagas’ disease) and T. brucei (cause of African sleeping sickness) are not closely related to each other. [9]

Phylogenetic analyses 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. [10]

Salivarians are trypanosomes of the subgenera of Duttonella , Trypanozoon , Pycnomonas and Nannomonas , which are passed to the vertebrate recipient in the saliva of the tsetse fly (Glossina spp.). [11] Antigenic variation is a characteristic shared by the Salivaria, which has been particularly well-studied in T. brucei . [12] The Trypanozoon subgenus contains the species Trypanosoma brucei , T. rhodesiense and T. equiperdum . The subgenus Duttonella contains the species T. vivax . Nannomonas contains T. congolense . [13]

Stercorians are trypanosomes passed to the recipient in the feces of insects from the subfamily Triatominae (most importantly Triatoma infestans ). [14] This group includes Trypanosoma cruzi , T. lewisi , T. melophagium , T. nabiasi , T. rangeli , T. theileri , T. theodori . [15] The subgenus Herpetosoma contains the species T. lewisi .

The subgenus Schizotrypanum contains T. cruzi [13] and a number of bat trypanosomes. The bat species include Trypanosoma cruzi marinkellei , Trypanosoma dionisii , Trypanosoma erneyi , Trypanosoma livingstonei and Trypanosoma wauwau . Other related species include Trypanosoma conorhini and Trypanosoma rangeli .[ citation needed ]

Evolution

The ancestor of modern trypanosomes absorbed a green alga around one billion years ago and co-opted some of its genetic material. This has resulted in modern trypanosomes such as T. brucei containing essential genes for the breakdown of sugars that are most closely related to plants. This difference may be used as the target of therapies. [16]

The relationships between the species have not been worked out to date. It has been suggested that T. evansi arose from a clone of T. equiperdum which lost its maxicircles. [17] It has also been proposed that T. evansi should be classified as a subspecies of T. brucei. [18]

It has been shown that T. equiperdum has emerged at least once in Eastern Africa and T. evansi at two independent occasions in Western Africa. [19]

Selected species

Species of Trypanosoma include the following:

Hosts, life cycle and morphologies

The six main morphologies of trypanosomatids. TrypanosomatidMorphologies PlainSVG.svg
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

Evidence has been obtained for meiosis in T. cruzi , and for genetic exchange. [25] 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. [26] [27] 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. [28]

Related Research Articles

<span class="mw-page-title-main">Chagas disease</span> Mammal parasitic disease

Chagas disease, also known as American trypanosomiasis, is a tropical parasitic disease caused by Trypanosoma cruzi. It is spread mostly by insects in the subfamily Triatominae, known as "kissing bugs". The symptoms change over the course of the infection. In the early stage, symptoms are typically either not present or mild, and may include fever, swollen lymph nodes, headaches, or swelling at the site of the bite. After four to eight weeks, untreated individuals enter the chronic phase of disease, which in most cases does not result in further symptoms. Up to 45% of people with chronic infections develop heart disease 10–30 years after the initial illness, which can lead to heart failure. Digestive complications, including an enlarged esophagus or an enlarged colon, may also occur in up to 21% of people, and up to 10% of people may experience nerve damage.

<span class="mw-page-title-main">African trypanosomiasis</span> Parasitic disease also known as sleeping sickness

African trypanosomiasis is an insect-borne parasitic infection of humans and other animals.

<span class="mw-page-title-main">Trypanosomatida</span> Group of single-celled parasitic organisms

Trypanosomatida is a group of kinetoplastid unicellular organisms distinguished by having only a single flagellum. The name is derived from the Greek trypano (borer) and soma (body) because of the corkscrew-like motion of some trypanosomatid species. All members are exclusively parasitic, found primarily in insects. A few genera have life-cycles involving a secondary host, which may be a vertebrate, invertebrate or plant. These include several species that cause major diseases in humans. Some trypanosomatida are intracellular parasites, with the important exception of Trypanosoma brucei.

<span class="mw-page-title-main">Tsetse fly</span> Genus of disease-spreading insects

Tsetse are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus Glossina, which are placed in their own family, Glossinidae. The tsetse is an obligate parasite, which lives by feeding on the blood of vertebrate animals. Tsetse has been extensively studied because of their role in transmitting disease. They have pronounced economic and public health impacts in sub-Saharan Africa as the biological vectors of trypanosomes, causing human and animal trypanosomiasis.

<span class="mw-page-title-main">Trypanosomiasis</span> Medical condition

Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma. In humans this includes African trypanosomiasis and Chagas disease. A number of other diseases occur in other animals.

<span class="mw-page-title-main">Carlos Chagas</span> Brazilian doctor and scientist (1879–1934)

Carlos Justiniano Ribeiro Chagas, or Carlos Chagas, was a Brazilian sanitary physician, scientist, and microbiologist who worked as a clinician and researcher. Most well known for the discovery of an eponymous protozoal infection called Chagas disease, also called American trypanosomiasis, he also discovered the causative fungi of the pneumocystis pneumonia. He described the two pathogens in 1909, while he was working at the Oswaldo Cruz Institute in Rio de Janeiro, and named the former Trypanosoma cruzi to honour his friend Oswaldo Cruz.

<i>Trypanosoma brucei</i> Species of protozoan parasite

Trypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extracellular and inhabits the blood plasma and body fluids. It causes deadly vector-borne diseases: African trypanosomiasis or sleeping sickness in humans, and animal trypanosomiasis or nagana in cattle and horses. It is a species complex grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense. The first is a parasite of non-human mammals and causes nagana, while the latter two are zoonotic infecting both humans and animals and cause African trypanosomiasis.

<i>Trypanosoma evansi</i> Contagious protist

Trypanosoma evansi is a parasitic species of excavate trypanosome in the genus Trypanosoma that is one cause of surra in animals. Discovered by Griffith Evans in 1880 at Dera Ismail Khan, it is the first known trypanosome that causes infection. It is a common parasite in India and Iran and causes acute disease in camels and horses, and chronic disease in cattle and buffalo. In Pakistan, it has been found to be the most prevalent trypanosome species in donkeys. It is now established to infect other mammals, including humans.

<span class="mw-page-title-main">David Bruce (microbiologist)</span> Scottish pathologist (1855–1931)

Major-General Sir David Bruce, was a Scottish pathologist and microbiologist who made some of the key contributions in tropical medicine. In 1887, he discovered a bacterium, now called Brucella, that caused what was known as Malta fever. In 1894, he discovered a protozoan parasite, named Trypanosoma brucei, as the causative pathogen of nagana.

Trypanosoma suis is a species of excavate trypanosome in the genus Trypanosoma that causes one form of the surra disease in animals. It infects pigs. It does not infect humans.

<span class="mw-page-title-main">Animal trypanosomiasis</span> Parasitic disease of vertebrates

Animal trypanosomiasis, also known as nagana and nagana pest, or sleeping sickness, is a disease of vertebrates. The disease is caused by trypanosomes of several species in the genus Trypanosoma such as T. brucei. T. vivax causes nagana mainly in West Africa, although it has spread to South America. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy, which lead to weight loss and anemia; in some animals the disease is fatal unless treated. The trypanosomes are transmitted by tsetse flies.

<i>Trypanosoma cruzi</i> Species of parasitic euglenoids (protozoans)

Trypanosoma cruzi is a species of parasitic euglenoids. Among the protozoa, the trypanosomes characteristically bore tissue in another organism and feed on blood (primarily) and also lymph. This behaviour causes disease or the likelihood of disease that varies with the organism: Chagas disease in humans, dourine and surra in horses, and a brucellosis-like disease in cattle. Parasites need a host body and the haematophagous insect triatomine is the major vector in accord with a mechanism of infection. The triatomine likes the nests of vertebrate animals for shelter, where it bites and sucks blood for food. Individual triatomines infected with protozoa from other contact with animals transmit trypanosomes when the triatomine deposits its faeces on the host's skin surface and then bites. Penetration of the infected faeces is further facilitated by the scratching of the bite area by the human or animal host.

Paratransgenesis is a technique that attempts to eliminate a pathogen from vector populations through transgenesis of a symbiont of the vector. The goal of this technique is to control vector-borne diseases. The first step is to identify proteins that prevent the vector species from transmitting the pathogen. The genes coding for these proteins are then introduced into the symbiont, so that they can be expressed in the vector. The final step in the strategy is to introduce these transgenic symbionts into vector populations in the wild. One use of this technique is to prevent mortality for humans from insect-borne diseases. Preventive methods and current controls against vector-borne diseases depend on insecticides, even though some mosquito breeds may be resistant to them. There are other ways to fully eliminate them. “Paratransgenesis focuses on utilizing genetically modified insect symbionts to express molecules within the vector that are deleterious to pathogens they transmit.” The acidic bacteria Asaia symbionts are beneficial in the normal development of mosquito larvae; however, it is unknown what Asais symbionts do to adult mosquitoes.

<span class="mw-page-title-main">Nifurtimox</span> Anti-parasitic medical drug

Nifurtimox, sold under the brand name Lampit, is a medication used to treat Chagas disease and sleeping sickness. For sleeping sickness it is used together with eflornithine in nifurtimox-eflornithine combination treatment. In Chagas disease it is a second-line option to benznidazole. It is given by mouth.

<span class="mw-page-title-main">Trypanothione synthase</span> Class of enzymes

In enzymology, a trypanothione synthase (EC 6.3.1.9) is an enzyme that catalyzes the chemical reaction

<i>Trypanosoma congolense</i> Protozoan parasite, cause of nagana

Trypanosoma congolense is a species of trypanosomes and is the major pathogen responsible for the disease nagana in cattle and other animals including sheep, pigs, goats, horses and camels, dogs, as well as laboratory mice. It is the most common cause of nagana in east Africa, but is also a major cause of nagana in west Africa. This parasite is spread by tsetse flies. In its mammalian host, Trypanosoma congolense only lives in blood vessels, and causes in particular anaemia.

Trypanosoma rangeli is a species of hemoflagellate excavate parasites of the genus Trypanosoma. Although infecting a variety of mammalian species in a wide geographical area in Central and South America, this parasite is considered non-pathogenic to these hosts. T. rangeli is transmitted by bite of infected triatomine bugs of the Reduviidae family, commonly known as barbeiro, winchuka(vinchuca), chinche, pito ou chupão.

Wendy Gibson is Professor of Protozoology at University of Bristol, specialising in trypanosomes and molecular parasitology.

<span class="mw-page-title-main">Variant surface glycoprotein</span>

Variant surface glycoprotein (VSG) is a ~60kDa protein which densely packs the cell surface of protozoan parasites belonging to the genus Trypanosoma. This genus is notable for their cell surface proteins. They were first isolated from Trypanosoma brucei in 1975 by George Cross. VSG allows the trypanosomatid parasites to evade the mammalian host's immune system by extensive antigenic variation. They form a 12–15 nm surface coat. VSG dimers make up ~90% of all cell surface protein and ~10% of total cell protein. For this reason, these proteins are highly immunogenic and an immune response raised against a specific VSG coat will rapidly kill trypanosomes expressing this variant. However, with each cell division there is a possibility that the progeny will switch expression to change the VSG that is being expressed. VSG has no prescribed biochemical activity.

The Sleeping Sickness Commission was a medical project established by the British Royal Society to investigate the outbreak of African sleeping sickness or African trypanosomiasis in Africa at the turn of the 20th century. The outbreak of the disease started in 1900 in Uganda, which was at the time a protectorate of the British Empire. The initial team in 1902 consisted of Aldo Castellani and George Carmichael Low, both from the London School of Hygiene and Tropical Medicine, and Cuthbert Christy, a medical officer on duty in Bombay, India. From 1903, David Bruce of the Royal Army Medical Corps and David Nunes Nabarro of the University College Hospital took over the leadership. The commission established that species of blood protozoan called Trypanosoma brucei, named after Bruce, was the causative parasite of sleeping sickness.

References

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  2. ↑ 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.
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  4. ↑ Büscher, Philippe; Cecchi, Giuliano; Jamonneau, Vincent; Priotto, Gerardo. "Human African trypanosomiasis". The Lancet. 390 (10110): 2397–2409. doi:10.1016/s0140-6736(17)31510-6. ISSN   0140-6736.
  5. ↑ 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.
  6. ↑ Valentin, G. 1841. Ueber ein Entozoon im Blute von Salmo fario. Müller's Archiv, p. 435.
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  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. ↑ 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
  11. ↑ "salivarian" . Retrieved 8 March 2019– via The Free Dictionary.
  12. ↑ 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
  13. 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
  14. ↑ Prevention, CDC-Centers for Disease Control and (2 May 2017). "CDC - Chagas Disease - General Information". www.cdc.gov. Retrieved 8 March 2019.
  15. ↑ "Stercoraria" . Retrieved 8 March 2019– via The Free Dictionary.
  16. ↑ Whitfield, John (2003). "Sleeping sickness bug swallowed a plant". Nature. doi:10.1038/news030127-3 . Retrieved 4 October 2021.
  17. ↑ Brun R, Hecker H, Lun ZR (1998) Trypanosoma evansi and T. equiperdum: distribution, biology, treatment and phylogenetic relationship (a review). Vet Parasitol 79(2):95-107
  18. ↑ 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
  19. ↑ 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
  20. ↑ 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
  21. ↑ 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.
  22. ↑ 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.
  23. ↑ 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
  24. ↑ 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.
  25. ↑ 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.
  26. ↑ 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.
  27. ↑ 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.
  28. ↑ 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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