Walsh & Hoyt: Trypanosoma Brucei (African Trypanosomiasis, Sleeping Sickness)

The agents of African sleeping sickness are flagellated protozoan parasites that belong to the genus Trypanosoma and the subgenus Trypanozoon. Only one species of Trypanosoma, T. brucei, causes the condition, although there are two subspecies of the organism that produce human disease: T. brucei rhodesiense, which is primarily a parasite of wild game but can infect humans, and T. brucei gambiense, which primarily infects humans. These two subspecies, along with a third subspecies, T. brucei brucei, that only infects wild and domestic animals and is not infectious forhumans, are indistinguishable morphologically and usually are referred to as a group: the T. brucei complex.