African trypanosomiasis is a human tropical parasitic disease usually caused by protozoan hemo-flagellates belonging to the complex Trypanosoma brucei. Two subspecies that are morphologically indistinguishable cause distinct disease patterns in humans. Trypanosoma brucei gambiense causes West African sleeping sickness and Trypanosoma brucei rhodesiense causes East African sleeping sickness.

Protozoan hemo-flagellates belonging to the complex Trypanosoma brucei cause African trypanosomiasis. Two subspecies that are morphologically indistinguishable cause distinct disease patterns in humans. Trypanosoma brucei gambiense causes West African sleeping sickness and Trypanosoma brucei rhodesiense causes East African sleeping sickness.

• The disease is caused by a parasite named Trypanosoma brucei rhodesiense, carried by the tsetse fly.
• An individual will contract East African trypanosomiasis if they are bitten by a tsetse fly infected with the Trypanosoma brucei rhodesiense parasite.
• The tsetse fly is common only in Africa.

• West African trypanosomiasis, also called Gambian sleeping sickness, is caused by a parasite called Trypanosoma brucei gambiense carried by the tsetse fly.
• An individual gets West African trypanosomiasis through the bite of an infected tsetse fly, found only in Africa.
• On rare occasions, a pregnant woman may pass the infection to her baby, or an individual may become infected through a blood transfusion or organ transplant.^[1]