Review on Trypanosoma vivax

Abstract

2 Abstract: Trypanosomosis is a protozoal disease caused by the genus Trypanosoma affecting human and animals mainly in sub-Saharan Africa and also in Latin America. Trypanosoma vivax (T.vivx) is transmitted cyclically by tsetse flies only found in Africa while the mechanical transmittion of T. vivax is worldwide problem including tsetse free regions of Africa. The disease is prevalent in two main regions of Ethiopia, northwest and southwest regions. The northwest region is paricularly affected by both tsetse and non-tsetse transmitted trypanosmosis and the dominant species of trypanosome is T. vivax. The molecular characterization of T. vivax from Brazil, Venezuela and West Africa (Nigeria), corroborating the West African origin of South American T. vivax, whereas a large genetic distance separated these isolates from the East African isolate (Kenya). The disease results in clinical syndromes such as anemia, emaciation and mortality. Anaemia appears with progressing parasitaemia resulting in a drop in packed cell volume (PCV). The ability of trypanosomes to change their surface-coat-antigen continuously leads to the exhaustion of the antibody production by the host leading to immunosuppression. T. vivax infections in West Africa are rapidly fatal compared to the East and Central Africa but there are exceptions to this rule. Occasional outbreaks of haemorrhagic T. vivax infections in Kenya are rapidly fatal. T. vivax infection can be diagnosed by clinical, parasitological, immunological and molecular methods. A pondered evaluation extrapolated for the total tsetse-infested lands values total loss, in terms of agricultural Gross Domestic Product, at US$ 4.75 billion per year. Studies on T. vivax in Latin America show that their economic impact can be quite severe. Control of the disease should combine treatment of infected animals and vector control. Eventhough, trypanocidal drugs will continue to play an important role in the integrated control of trypanosomosis, the development of trypanosome resistance to trypanocides is a continuous threat to their sustainable use. The available information on the pathogenic difference, drug resistance problems and genetic composition of T. vivax in relation to geographical locations and in different species of hosts is not yet elucidated in Ethiopia and hence requires thorough investigations.