Detección de la heterogeneidad molecular de Trypanosoma cruzi / Detection of molecular heterogeneity of Trypanosoma cruzi

Congenital transmission of T. cruzi in Cochabamba affects 6% of newborns from infected mothers. Only limited information is available on the type of transmitted parasites. However, it is well established that T. cruzi isolated from various vectors as well from host animals are highly heterogeneous. In our presentation we analyse aspects of molecular heterogeneity of T. cruzi and we review methods used for the molecular typing of T. cruzi lineages. Experimentally, we performed the PCR amplification of [quot ]Sequence-characterised region Markers[quot ] for typing T. cruzi isolated from umbilical blood of newborns in Cochabamba. We compared these results with those we obtained from general infected population. All 16 analysed, congenitally infected samples were of lineage IId. Our data also indicated that this lineage was found in about 80% of samples originated from general infected population in Cochabamba.

Comparación de métodos de PCR para el diagnóstico de la infección congenita por Trypanosoma cruzi / Comparison of PCR methods for the diagnosis of congenital Trypanosoma cruzi infection

PCR is a potentially interesting diagnostic tool to detect congenital T. cruzi infection. We have compared the sensitivity and capacity of a battery of T. cruzi PCR primers to detect the complete spectrum of known T. cruzi lineages, in order to improve and simplify the detection of infection in neonatal blood. We found that the primers Tcz1/Tcz2, targeting the 195 bp satellite repeat, detected all the parasitic lineages with the same sensitivity For all other tested primers (nDNA primers: BP1/BP2, 01/02, Pon1/ Pon2 and Tca1/Tca2; kDNA primers: S35VS36, 121/122), either, the intensity of amplicons varied according to T. cruzi lineages, or the assess were less sensitive. In order to better assess such PCR protocol, we assayed 311 samples of neonatal blood previously tested with parasitological methods. Reliability of our PCR test was demonstrated since all the 18 blood samples from newborns with congenital T. cruzi infection were positive, whereas the remaining samples (30 from control newborns of uninfected mothers and 262 out of 263 from babies, parasitologically negative, born from infected mothers) were negative. As our PCR method is simple, reliable, robust and cheap, it appears suitable for the detection of T. cruzi infection in neonatal blood.