Sleeping sickness. Light micrograph (LM) of Trypanosoma brucei, a cause of sleeping sickness, in blood. The long thin T. brucei can be seen amongst the red blood cells. The two morphologically identical species of this parasitic protozoan, or single-celled organism, are T. brucei gambiense and T. brucei rhodesiense. Trypanosomiasis, or sleeping sickness, occurs in tropical Africa, and is spread by the bite of the tsetse fly (Glossina sp.). Symptoms include headaches, confusion and severe tiredness. Unless treated with drugs, coma and death will result. Stained with Giemsa. Magnification: x450 when printed at 10 centimetres wide.