GENETIC-RELATIONSHIPS BETWEEN TRYPANOSOMA-CRUZI STRAINS ISOLATED FROMCHRONIC CHAGASIC PATIENTS IN SOUTHERN BRAZIL AS REVEALED BY RAPD AND SSR-PCR ANALYSIS

30 Trypanosoma cruzi strains isolated from chronic chagasic patients w ere studied at the genotype level by RAPD with arbitrary primers and S SR-PCR analysis. The genetic distance of strains was measured by the p ercentage of unshared bands. The results showed that the strains isola ted from chronic patients from different Chagas' disease endemic areas of Brazil constituted a broad group significantly more correlated tha n reported in previous studies, presenting RAPD profiles with an avera ge of 71% of shared bands and SSR-PCR patterns with a mean of 59% of s hared bands. In contrast to other findings in the literature, these st rains did not group on the basis of their geographic origin. These res ults suggest that a special adaptation of a parasite population in hum an hosts from mixed infective T. cruzi populations circulating in natu re may have occurred. (C) 1998 Elsevier Science B.V. All rights reserv ed.