Trypanosoma brucei is a single-celled parasite that causes sleeping sickness in humans and Nagana in animals. It is transmitted primarily by the bite of the tsetse fly, which is found in sub-Saharan Africa. The parasite exists in two main forms: Trypanosoma brucei gambiense, which causes the chronic form of sleeping sickness, and Trypanosoma brucei rhodesiense, responsible for the acute form. Once inside the host, Trypanosoma brucei multiplies in the bloodstream and can invade the central nervous system, leading to severe neurological symptoms. Early diagnosis and treatment are crucial, as the disease can be fatal if left untreated. Control measures focus on reducing tsetse fly populations and screening at-risk populations.