Trypanosoma cruzi Discret Typing Units (TcII and TcVI) in samples of patients from two municipalities of the Jequitinhonha Valley, MG, Brazil, using two molecular typing strategies

Abstract

BackgroundTrypanosoma cruzi is classified into six discrete taxonomic units (DTUs). For this classification, different biological markers and classification criteria have been used. The objective was to identify the genetic profile of T. cruzi samples isolated from patients of two municipalities of Jequitinhonha Valley, MG, Brazil.MethodsMolecular characterization was performed using two different criteria for T. cruzi typing to characterize 63 T. cruzi samples isolated from chronic Chagas disease patients. The characterizations followed two distinct methodologies. Additionally, the RAPD technique was used to evaluate the existence of genetic intragroup variability.ResultsThe first methodology identified 89 % of the samples as TcII, but it was not possible to define the genetic identity of seven isolates. The results obtained with the second methodology corroborated the classification as TcII of the same samples and defined the classification of the other seven as TcVI. RAPD analysis showed lower intra-group variability in TcII.ConclusionsThe results confirmed the preliminary data obtained in other municipalities of the Jequitinhonha Valley, showing a predominance of TcII, similar to that verified in northeast/south axis of Brazil and the first detection of TcVI in the study region. The second protocol was more simple and reliable to identify samples of hybrid character.

Performance of TcI/TcVI/TcII Chagas-Flow ATE-IgG2a for universal and genotype-specific serodiagnosis of Trypanosoma cruzi infection

“…cruzi infection, most based on molecular biology approaches present distinct levels of complexity and in general display high specificity but moderate sensitivity [4, 10–12, 46–52]. Moreover, a combination of several genetic markers is necessary to detect and distinguish the T .…”

“…Moreover, a combination of several genetic markers is necessary to detect and distinguish the T . cruzi genotypes [10–12]. Furthermore, the majority of these methods can not directly be performed in biological and clinical samples, requiring previous parasite isolation by hemoculture/xenoculture followed by in vitro growth and maintenance that may lead to clonal selection [14,53–55].…”

“…However, none of these methods allows a full resolution when used individually and a combinatory three-marker sequential typing strategy is usually required to confirm the T . cruzi genotype [10–12]. Straightforward, genotyping methods to identify the T .…”

Chagas Disease in the United States: a Public Health Approach

“…Sylvatic TcI populations are characterized by high levels of genetic diversity (127)(128)(129)(130)(131)(132)(133), while human infections are associated with divergent, more genetically homogenous strains (131,(134)(135)(136). By contrast, TcII, TcV and TcVI appear less variable overall (103) and are predominant in domestic cycles in the Southern Cone (115,137,138). However, recent whole genome sequencing of clinical TcII isolates has revealed more extensive intra-DTU diversity than previously reported (113).…”

Accomplishing the genotype-specific serodiagnosis of single and dual Trypanosoma cruzi infections by flow cytometry Chagas-Flow ATE-IgG2a

“…In general, the molecular approaches require the use of several genetic markers to distinguish the T . cruzi genotype [ 22 – 24 ]. Moreover, in cases of mixed infections, the molecular tests may identify distinct T .…”