Biological characterization of Trypanosoma cruzi strains

Biological parameters of five Trypanosoma cruzi strains from different sour ces were determined in order to know the laboratory behaviour of natural po pulations. The parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and genti an violet. Differences in transformation to metacyclic, in the percentage o f infected cells as well as in the number of amastigotes per cell were obse rved among the strains. Regarding to pharmacological assays, Y strain was t he most sensitive to the three assayed compounds. These data demonstrate th e heterogeneity of natural population of T. cruzi, the only responsible of infection in humans.