Trypanosoma

Trypanosoma
Trypanosoma sp. among red blood cells.
Scientific classification
Domain: Eukaryota
Kingdom: Excavata
Phylum: Euglenozoa
Class: Kinetoplastida
Order: Trypanosomatida
Genus: Trypanosoma
Gruby, 1843
This article is about the genus Trypanosoma, for the specific human pathogens see Trypanosoma brucei and Trypanosoma cruzi.

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 to complete life cycle) and are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. Then in the invertebrate host they are generally found in the intestine and normally occupy the bloodstream or an intracellular environment in the mammalian host.

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

Contents

Selected species

Species of Trypanosoma include the following:

Hosts, life cycle and morphologies

See also: Trypanosomatid

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

Stercorarian trypanosomes infect the insect, most often the triatomid kissing bug, develop in its posterior gut and infective organisms are released in the faeces and deposited on the skin of the host. The organism then penetrates and can disseminate throughout the body. Insects become infected when taking a blood meal.

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.

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.

References

  1. ^ 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. http://linkinghub.elsevier.com/retrieve/pii/S0020-7519(04)00189-4. 
  2. ^ 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. 
  3. ^ 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. http://linkinghub.elsevier.com/retrieve/pii/S0035-9203(05)00429-3. 
  4. ^ 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. http://www.veterinaryresearch.org/content/42/1/63. 

External links