Trypanosoma evansi
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 (British India), 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.
| Trypanosoma evansi | |
|---|---|
| Trypanosoma evansi in blood | |
| Scientific classification | |
| Domain: | Eukaryota |
| Phylum: | Euglenozoa |
| Class: | Kinetoplastea |
| Order: | Trypanosomatida |
| Family: | Trypanosomatidae |
| Genus: | Trypanosoma |
| Species: | T. evansi |
| Binomial name | |
| Trypanosoma evansi (Steel) Chauvrat, 1896 | |
| Synonyms | |
|
Trypanosoma brucei evansi | |
It has been proposed that T. evansi is—like T. equiperdum—a derivative of T. brucei. Due to the loss of part of the mitochondrial (kinetoplast) DNA T. evansi is not capable of infecting tsetse flies, the usual invertebrate vectors of trypanosomes, and establishing the subsequent life-stages. Due to its mechanical transmission T. evansi shows a very broad vector specificity including members of the genera Tabanus, Stomoxys, Haematopota, Chrysops and Lyperosia. It rarely causes disease in humans, but human infections are common. Haemoglobin plays a role in trypanolytic host defense against T. evansi.