Abstract
The fine structure of bloodstream forms of Trypanosoma brucei cultivated in vitro, and of trypanosomes from lymph and blood of mammalian hosts, was compared morphometrically. The cell volume, quantitative parameters of the mitochondrion and of glycosomes were mainly investigated. A Coulter Channelyzer was used for the first time to measure the mean cell volume of living parasites. In vitro, the monomorphic trypanosomes between the feeder layer cells showed lower values for mitochondrial parameters than the slightly pleomorphic forms from the supernatant medium. Trypanosomes in culture were very similar morphologically to forms from lymph nodes of rats. Despite some morphometric differences between cultivated blood stream forms and those grown in vivo, the similarity of both populations was clear. Both populations, however, differed significantly from stages found in the vector or from procyclic culture forms.