Human African trypanosomiasis

The parasite

Trypanosomes are unicellular parasitic protozoa belonging to the Trypanosoma Genus of the Trypanosomatidae Class (Protozoa Kingdom). A large number of species and subspecies of trypanosomes have been described. Different species of trypanosomes infect a variety of different vertebrates, including animals and humans. Most species are transmitted by insects.

On the African continent a number of Trypanosoma species and subspecies are economically significant causing human and animal diseases which are an obstacle to human welfare, affecting cattle rearing and agricultural development.

Human African Trypanosomiasis or sleeping sickness, only occurs in Sub-Saharan Africa. It is caused by two subspecies of Trypanosoma brucei brucei, namely Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. Wild and domestic animals can host these parasites and may represent under particular conditions an important reservoir of infection for the tsetse flies.

Animal African Trypanosomiasis is caused by other trypanosome species and subspecies then those affecting human beings. Trypanosoma brucei, Trypanosoma congolense, Trypanosoma equiperdum, Trypanosoma simiae, Trypanosoma suis and Trypanosoma vivax are some of the species and subspecies causing diseases in wild and domestic animals. These diseases bear different common names such as nagana, dourine and surra. All these diseases have an economic impact on the development of agriculture in Africa. Those affecting cattle are undoubtedly the most important economically since they are a major cause for reduced meat and milk production and draught power for agricultural production.

Occasional infections in humans with T. evansi, T lewisi, T. brucei brucei and, T congolense have been describing in human beings. However little is known on the public health importance of these diseases.

For more on Animal African Trypanosomiasis visit the Food and Agriculture Organization of the United Nations.
the Food and Agriculture Organization of the United Nations

Trypanosoma cruzi is not found on the African continent but causes Chagas disease, a devastating human disease in The Americas.
Chagas disease