Chagas disease corresponds to a parasitic infection caused by the flagellate protozoan Trypanosoma cruzi. This parasite has great genetic diversity and is currently divided into six Discrete Typing Units (DTUs) classified as TcI - TcVI. The disease can be caused by any of the genotypes or DTUs because they are infectious for humans. Diagnostic methods for T. cruzi parasitaemia can be classified into three main groups: parasitological, serological, and molecular. However, during the chronic phase, characterised by a reduced number of circulating parasites, the first two methods present limitations for routine diagnosis. Parasitological tests can present low sensitivity and immunological tests can present problems of low specificity mainly due to cross reactions with other related parasites, such as Leishmania spp. and T. rangeli. For this reason, molecular techniques have shown promising results to characterise the diversity of T. cruzi. In a previous study in our laboratory, we standardised the protocol of Da Cruz Moreira and Ramirez (2019) to typify the DTUs of Trypanosoma cruzi from whole blood of chronic chagasic patients from the Province of Misiones by using conventional PCR. In accordance with the author’s description, we have managed to detect the different DTUs despite the fact that the parasite load is very low during the chronic phase. However, with this protocol, multiple conventional PCR reactions and subsequent sequencing reactions are necessary, which makes these tests cumbersome, time-consuming and the results are difficult to interpret due to the presence of nonspecific bands. Therefore, to solve this problem, we propose to develop a highly sensitive technique such as real-time PCR, which allows the distinction of the six DTUs in a few steps in biological and clinical samples.
Keywords: Chagas disease, Trypanosoma cruzi, DTUs
Start date: 2022-01-01
