Trypanosoma

Trypanosoma are of the class kinetoplastida, a monophyletic group of unicellular parasitic protozoa. The name is derived from the Greek trypa&ocirc; (boring) and soma (body) because of their corkscrew-like motion. Trypanosomes infect a variety of hosts and cause the fatal disease sleeping sickness in humans.

Trypanosoma undergo a complex lifecycle 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.

Characteristic of this order is the mitochondrial genome, known as the kinetoplast. This is made up of a highly complex series of catenatated circles and minicircles and require a cohort of proteins for organisation during cell division.

Trypanosomes have a number of biologically interesting features that has made them the object of study. For example, Trypanosomes do their genetic regulation post-transcriptionally, are a classic model of antigenic variation, and edit their mitochondrial mRNA transcripts using short guide RNAs encoded in mitochondrial minicircles as templates. In addition, two life cycle forms of Trypanosoma brucei are easy to culture and are genetically pliable.

Species of Trypanosoma include the following:
 * T. avium, which causes trypanosomiasis in birds
 * T. boissoni, in elasmobranch
 * T. brucei, which causes sleeping sickness in humans and nagana in cattle
 * T. carassii, in freshwater teleosts
 * T. cruzi, which causes Chagas disease in humans
 * T. congolense, which causes nagana in cattle, horses, and camels
 * Trypanosoma equinum Voges 1901, Horses infected by Tabanidae, South America
 * 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 (single case report of human infection in 2005 in India and was successfully treated with suramin. )
 * Trypanosoma levisi, in rats
 * Trypanosoma melophagium Sheep infected by Melophagus ovinus
 * Trypanosoma percae in fish: Perca fluviatilis
 * Trypanosoma rangeli, believed to be nonpathogenic to humans
 * T. rotatorium in amphibian,
 * T. simiae, which causes nagana in animals
 * 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