Direct identification of Trypanosoma cruzi natural clones in vectors and mammalian hosts by polymerase chain reaction amplification.

The polymerase chain reaction was used to amplify the highly variable region of the kinetoplast minicircle of Trypanosoma cruzi directly in biological samples (feces of infected Triatomine bugs, blood samples of experimentally infected mice, and artificially infected human blood samples). Hybridization of the amplified DNAs with reference stocks representing different genotypes (natural clones) enabled us to characterize the stocks infecting the biological samples under study. The main interest of this new approach is the diagnosis of T. cruzi infection and simultaneous direct identification of the different natural clones circulating in vectors and mammalian blood without isolation of the stocks. The suitability of this technique for epidemiologic studies is also discussed.