[Biological characterization of clones of the Y, CL and MR strains of Trypanosoma cruzi in inbred C3H mice].

Ten clones of Trypanosoma cruzi isolated from Y, CL and MR strains were studied. The infectivity of culture forms, parasitemia pattern, polymorphism and mortality were studied in C3H inbred mice. Significant intra-group differences among Y and CL clones were found. MR clones showed higher homogeneity. These data indicate that T. cruzi strains can show different degrees of heterogeneity. It is suggested that conditions used to maintain T. cruzi strains may result in a selective advantage for some subpopulations (clones) after many years of laboratory maintenance.