Identification and Detection of Trypanosoma cruzi by Using a DNA Amplification Fingerprint Obtained from the Ribosomal

We designed a PCR assay targeted on repeated elements of the ribosomal intergenic spacer which produces highly polymorphic DNA band patterns for different strains of Trypanosoma cruzi. By labeling the PCR products with digoxigenin and by chemiluminescence detection, we improved the assay sensitivity by three orders of magnitude to get T. cruzi strain fingerprints in feces of the trypanosome-infected triatomine bug vector. We also developed a capture assay for the digoxigenin-labeled PCR products that allowed us to detect T. cruzi in triatomine bug vector feces and in human serum samples with a solid support. The flagellated protozoan Trypanosoma cruzi causes American human trypanosomiasis, or Chagas ' disease. In Latin America, it is the major cause of morbidity and mortality in the rural population (12); the parasite is usually transmitted by blood-sucking triatomine bugs, but alterna-tive routes, such as blood transfusion, congenital transmis-sion, organ transplantation, and laboratory accidents, are frequently reported. There is an urgent need for precise and sensitive diagnostic techniques in the chronic stages of th