Characterization of West African <i>Trypanosoma (Trypanozoon) brucei</i> isolates from man and animals using isoenzyme analysis and DNA hybridization

A total of 18 West African </>Trypanosoma (Trypanozoon) brucei</i> stocks isolated from man and animals were characterized using isoenzyme analysis with isoelectric focusing (IEF) and DNA hybridization. They were compared with four <i>T. (T.) brucei</i> isolates from East and West Africa that had previously been analysed and well defined. All experiments were carried out with cell lysates of procyclic trypanosomes produced in vitro. The different stocks could be separated into two distinct groups according to their isoenzyme and DNA patterns. The homogeneous group of <i>T. b. gambiense</i> was characterized by zymodeme A and highly specific DNA-banding patterns (type G) always associated with stable human serum resistance. The <i>non-gambiense</i> group (consisting of <i>T.b. rhodesiense</i> and <i>T. b. brucei</i>) was determined by a great variation in these markers. Our results clearly indicate the existence, of <i>T. b. rhodesiense</i>-like parasites in West African patients. Due to their lack of human serum resistance, the four characterized animal isolates can be referred to as <i>T. b. brucei</i>.