In vitro development of metacyclic Trypanosoma simiae derived from bloodstream trypomastigotes.

A stock of Trypanosoma simiae was transformed into procyclic forms at 26 C in a semi-defined maintenance medium. After transformation, the trypanosomes were maintained in a modified Eagle's MEM medium. On day 35 of cultivation, epimastigotes attached to the bottom of the culture flask. From day 44 onwards, metacyclic-like trypanosomes were observed. Subcutaneous injections into pigs of trypanosome suspensions obtained from cultures on day 10 were not infective, whereas culture-derived metacyclics (days 44, 63 and 69) were highly pathogenic.