What disease does the tsetse fly cause?

The tsetse fly transmits a disease called African trypanosomiasis also known as sleeping sickness. It is caused by parasitic protozoa of the genus Trypanosoma brucei which is transmitted by the bite of infected tsetse flies (Glossina species). There are two forms of the disease : (1) West African sleeping sickness, caused by Trypanosoma brucei gambiense, and (2) East African sleeping sickness, caused by Trypanosoma brucei rhodesiense.