Trypanosoma
Encyclopedia
- This article is about the genus Trypanosoma, for the specific human pathogens see Trypanosoma bruceiTrypanosoma bruceiTrypanosoma brucei is a parasitic protist species that causes African trypanosomiasis in humans and nagana in animals in Africa. There are 3 sub-species of T. brucei: T. b. brucei, T. b. gambiense and T. b. rhodesiense.These obligate parasites have two hosts - an insect vector and mammalian host...
and Trypanosoma cruziTrypanosoma cruziTrypanosoma cruzi is a species of parasitic euglenoid trypanosomes. This species causes the trypanosomiasis diseases in humans and animals in America...
.
Trypanosoma is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of kinetoplastid
Kinetoplastid
The kinetoplastids are a group of single-cell flagellate protozoa, including a number of parasites responsible for serious diseases in humans and other animals, as well as various forms found in soil and aquatic environments...
s (class Kinetoplastida), a monophyletic group of unicellular parasitic flagellate
Flagellate
Flagellates are organisms with one or more whip-like organelles called flagella. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants...
protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
. The name is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
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
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
and normally occupy the bloodstream or an intracellular
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...
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
Trypanosoma brucei
Trypanosoma brucei is a parasitic protist species that causes African trypanosomiasis in humans and nagana in animals in Africa. There are 3 sub-species of T. brucei: T. b. brucei, T. b. gambiense and T. b. rhodesiense.These obligate parasites have two hosts - an insect vector and mammalian host...
, and Chagas disease
Chagas disease
Chagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...
, caused by Trypanosoma cruzi
Trypanosoma cruzi
Trypanosoma cruzi is a species of parasitic euglenoid trypanosomes. This species causes the trypanosomiasis diseases in humans and animals in America...
.
The mitochondrial genome of the Trypanosoma, as well as of other kinetoplastids, known as the kinetoplast
Kinetoplast
A kinetoplast is a disk-shaped mass of circular DNA inside a large mitochondrion that contains many copies of the mitochondrial genome. Kinetoplasts are only found in protozoa of the class Kinetoplastida...
, is made up of a highly complex series of catenated circles and minicircles and requires a cohort of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s for organisation during cell division
Cell division
Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...
.
Selected species
Species of Trypanosoma include the following:- T. ambystomae in amphibianAmphibianAmphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s - T. antiquusTrypanosoma antiquusTrypanosoma antiquus is an extinct species of kinetoplastid , a monophyletic group of unicellular parasitic flagellate protozoa....
Extinct (Fossil in Eocene amber) - T. avium, which causes trypanosomiasisTrypanosomiasisTrypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma. Approximately 500,000 men, women and children in 36 countries of sub-Saharan Africa suffer from human African trypanosomiasis which is caused by...
in birds - T. boissoni, in elasmobranch
- T. bruceiTrypanosoma bruceiTrypanosoma brucei is a parasitic protist species that causes African trypanosomiasis in humans and nagana in animals in Africa. There are 3 sub-species of T. brucei: T. b. brucei, T. b. gambiense and T. b. rhodesiense.These obligate parasites have two hosts - an insect vector and mammalian host...
, which causes sleeping sickness in humans and naganaNaganaNagana, also known as nagana pest or animal African trypanosomiasis, is a disease of vertebrate animals. The disease is caused by trypanosomes of several species in the genus Trypanosoma. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy, which lead to...
in cattle - T. cruziTrypanosoma cruziTrypanosoma cruzi is a species of parasitic euglenoid trypanosomes. This species causes the trypanosomiasis diseases in humans and animals in America...
, which causes Chagas diseaseChagas diseaseChagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...
in humans - T. congolense, which causes naganaNaganaNagana, also known as nagana pest or animal African trypanosomiasis, is a disease of vertebrate animals. The disease is caused by trypanosomes of several species in the genus Trypanosoma. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy, which lead to...
in ruminant livestock, horses and a wide range of wildlife - T. equinum, in South American horses, transmitted via Tabanidae,
- T. equiperdumTrypanosoma equiperdumTrypanosoma equiperdum is a protozoan that causes Dourine, or covering sickness, in horses and other animals in the family equidae. The donkey shows no symptoms but is a carrier of this parasite. Unlike other species of Trypanosoma, this parasite can be sexually transmitted, also mother foal...
, which causes dourine or covering sicknessCovering sicknessCovering sickness, or dourine , is a disease of horses and other members of the family equidae...
in horseHorseThe horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s and other EquidaeEquidaeEquidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...
, it can be spread through coitus. - T. evansiTrypanosoma evansiTrypanosoma evansi is a protozoan trypanosome in the genus trypanosoma that causes one form of the surra disease in animals. It has been proposed that T. evansi is - like T. equiperdum- originally a subspecies of T. brucei brucei. Due to this loss of part of the mitochondrional DNA T...
, which causes one form of the disease surraSurraSurra is a disease of vertebrate animals. The disease is caused by protozoan trypanosomes, specifically Trypanosoma evansi, of several species which infect the blood of the vertebrate host, causing fever, weakness, and lethargy which lead to weight loss and anemia...
in certain animals (a single case report of human infection in 2005 in India was successfully treated with suraminSuraminSuramin is a drug developed by Oskar Dressel and Richard Kothe of Bayer, Germany in 1916, and is still sold by Bayer under the brand name Germanin.According to the National Cancer Institute there are no active clinical trials...
) - T. everetti, in birds
- T. hosei in amphibianAmphibianAmphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s - T. levisi, in rats
- T. melophagium, in sheep, transmitted via Melophagus ovinusMelophagus ovinusMelophagus ovinus, or the sheep ked, is a brown, hairy fly that resembles a tick. This wingless fly is about 4 to 6 mm long and has a small head, is a fly from the family Hippoboscidae. They are blood-feeding parasites of sheep. The legs of the sheep ked are very strong and are tipped with...
- T. paddae, in birds
- T. parroti, in amphibians
- T. percae, in the species Perca fluviatilis
- T. rangeliTrypanosoma rangeliTrypanosoma rangeli is a species of Trypanosoma.It is considered nonpathogenic in humans.It has been proposed for use in the prevention of Chagas disease....
, believed to be nonpathogenic to humans - T. rotatorium, in amphibians
- T. rugosae, in amphibians
- T. sergenti, in amphibians
- T. simiae, which causes naganaNaganaNagana, also known as nagana pest or animal African trypanosomiasis, is a disease of vertebrate animals. The disease is caused by trypanosomes of several species in the genus Trypanosoma. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy, which lead to...
in pigs. Its main reservoirs are warthogs and bush pigs - T. sinipercae, in fishes
- T. suisTrypanosoma suisTrypanosoma suis is a protozoan trypanosome in the genus Trypanosoma that causes one form of the surra disease in animals. It infects pigs. It does not infect humans.-Discovery:...
, which causes a different form of surraSurraSurra is a disease of vertebrate animals. The disease is caused by protozoan trypanosomes, specifically Trypanosoma evansi, of several species which infect the blood of the vertebrate host, causing fever, weakness, and lethargy which lead to weight loss and anemia... - T. theileri, a large trypanosome infecting ruminants
- T. triglae, in marine teleosts
- T. vivax, which causes the disease naganaNaganaNagana, also known as nagana pest or animal African trypanosomiasis, is a disease of vertebrate animals. The disease is caused by trypanosomes of several species in the genus Trypanosoma. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy, which lead to...
, mainly in West Africa, although it has spread to South America
Hosts, life cycle and morphologies
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
Triatoma
Triatoma is a genus of assassin bug in the subfamily Triatominae The members of Triatoma are blood-sucking insects that can transmit serious diseases, such as Chagas disease....
, 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
Tsetse fly
Tsetse , sometimes spelled tzetze and also known as tik-tik flies, are large biting flies that inhabit much of mid-continental Africa between the Sahara and the Kalahari deserts. They live by feeding on the blood of vertebrate animals and are the primary biological vectors of trypanosomes, which...
, and infective organisms are innoculated 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 vertibrate host and the trypomastigote or promastigote form in the gut of the invertebrate host. Intracellular lifecycle stages are normally found in the amastigote
Amastigote
An amastigote is a cell that does not have a visible external flagella or cilia. The term is used mainly to describe a certain phase in the life-cycle of trypanosome protozoans. It is also called the leishmanial stage, since in Leishmania it is the form the parasite takes in the vertebrate host,...
form. The trypomastigote morphology is unique to species in the genus Trypanosoma.
External links
- Trypanosoma reviewed and published by Wikivet, accessed 08/10/2011.
- Trykipedia, Trypanosomatid specific ontologies
- Tree of Life: Trypanosoma