FIG 1.

Biological behavior of selected TcI isolates of T. cruzi in mice. Swiss mice were infected with Colombiana (COL), Sylvio X10 (SYL), and TCC strains of T. cruzi (n = 6 per group), as described in Materials and Methods. (A) Blood parasitemia was monitored by light microscopy (10 microscopic fields per sample). (B) Representative H&E staining (blue, nuclear; pink, muscle, cytoplasm, or keratin) of heart tissue sections from COL-, SYL-, and TCC-infected mice, harvested during the chronic disease phase (>120 days postinfection [p.i.]; magnification, ×10). In all figures, data are presented as means ± the SD, and significance is indicated as follows: *, P < 0.05; **, P < 0.01; and ***, P < 0.001.