Trypanosoma cruzi: parasite detection and strain discrimination in chronic chagasic patients from northeastern Brazil using PCR amplification of kinetoplast DNA and nonradioactive hybridization.

摘要: Blood samples from 172 individuals northeastern Brazil were subjected to PCR amplification of Trypanosoma cruzi-specific kDNA sequences. This method enabled us detect parasite DNA in 21 47 patients that serologically positive, In addition, 1 patient gave doubtful results with chagasic serology was confirmed as positive by PCR. We applied the same detection feces wild triatomines captured region, obtaining three microscopic examination. The 25 amplified products obtained this study then reamplified primers a final amplicon containing sequences most variable region minicircles. These used probes hybridization experiments aimed at defining degree relatedness between strains infecting humans and insects based on homologies. found related showed no crosshybridization those human infections. Eight infections cross-hybridization did not hybridize other patients. indicates T. cruzi circulating present high level genetic heterogeneity. Finally, number hybridized amplicons each other, indicating population presenting mixed content (either due different or hybrid parasite) are more frequent event than previously thought.