Trypanosoma cruzi pathogenesis and histotropism: don ́t forget analizing DTU and parasite populations when studying the infection

BURGOS, JUAN M.

Mar del Plata

Congreso; XXXI Reunión Anual Sociedad Argentina de Protozoología; 2020

Chagas disease, caused by Trypanosoma cruzi, is one of the most important parasiticinfection in America. With a prevalence of about 8 million people, it primarily affects ruralpopulations but also migrant ones in Americas´ cities and all around the world.Pathological outcomes ranges from subclinical infection to cardiac and digestivesyndromes, SNC affection, and death. In 2009 six Discrete Typing Units (DTU) weredefine into the specie, where each group is identifiable by common molecular markers andconstitute reliable units for molecular epidemiology and evolution analysis. Differentapproaches, alone or in combination, are well accepted to determine parasite DTUs. PCRamplification of multicopy polymorphic sequences (SL intergenic region, 24Sα rDNA, 18SrDNA, the A10 fragment), PCR-RFLP of genes (HSP60, GPI, COII, TcSC5D, TcMK), orDNA sequencing (kDNA, TcSC5D) are used to determine T. cruzi DTUs, while otherstrategies (e.g. kDNA-PCR-RFLP) allow intra-DTU parasite populations comparison. Withvery different prevalences along the continent, all DTUs are observe in human infections.Although the association between them and the evolution of the infection and pathogeniadevelopment is still uncertain, researches information collection along years allowedobserve the presence of behaviors that demand the DTU and intra-DTU analysis for a bettercomprehension of it. Clonal histotropism, differential virulence and response against drugsare some of the phenomenon observed. In this sense blood parasites, easily characterizable,may not be related to those populations damaging tissues. Moreover, for accuracy parasitequantification by real time PCR, DTU identity should be determined due to differentgenetic burden among them. Complexity of natural infections, usually multiclonal, besideshost genetic background make the truly understanding of the infection and its evolution achallenge, where the parasite DTU determination is an important piece in the diseasejigsaw.