Evaluation of the in vitro transformation technique to distinguish Trypanosoma evansi from cyclically transmitted Trypanozoon stocks.

In order to initiate transformation into procyclic forms, bloodstream trypanosomes, were transferred to semi-defined medium at 27 degrees C. All stocks previously classified as Trypanosoma brucei rhodesiense, T.b. gambiense and T.b. brucei transformed into procyclic forms. None of the 31 characterized T. evansi stocks transformed into procyclic forms, but died between day 4 and day 6 in culture. On the other hand, 3 out of 64 stocks of monomorphic brucei subgroup field isolates from camels transformed into procyclic forms, confirming the existence of T.b. brucei infection in camels kept close to tsetse belts.