Trypanosoma


 * 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 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.

Selected species
Species of Trypanosoma include the following:
 * T. ambystomae in amphibians
 * T. antiquus Extinct (Fossil in Eocene amber)
 * 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 of 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 was successfully treated with suramin )
 * 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 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, life cycle and morphologies
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 vertibrate 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.