Association between Trypanosoma cruzi DTU TcII and chronic Chagas disease clinical presentation and outcome in an urban cohort in Brazil

Abstract

Background The specific roles of parasite characteristics and immunological factors of the host in Chagas disease progression and prognosis are still under debate. Trypanosoma cruzi genotype may be an important determinant of the clinical chronic Chagas disease form and prognosis. This study aimed to identify the potential association between T. cruzi genotypes and the clinical presentations of chronic Chagas disease. Methodology/principal findings This is a retrospective study using T. cruzi isolated from blood culture samples of 43 patients with chronic Chagas disease. From 43 patients, 42 were born in Brazil, mainly in Southeast and Northeast Brazilian regions, and one patient was born in Bolivia. Their mean age at the time of blood collection was 52.4±13.2 years. The clinical presentation was as follows 51.1% cardiac form, 25.6% indeterminate form, and 23.3% cardiodigestive form. Discrete typing unit (DTU) was determined by multilocus conventional PCR. TcII (n = 40) and TcVI (n = 2) were the DTUs identified. DTU was unidentifiable in one patient. The average follow-up time after blood culture was 5.7±4.4 years. A total of 14 patients (32.5%) died and one patient underwent heart transplantation. The cause of death was sudden cardiac arrest in six patients, heart failure in five patients, not related to Chagas disease in one patient, and ignored in two patients. A total of 8 patients (18.6%) progressed, all of them within the cardiac or cardiodigestive forms. Conclusions/significance TcII was the main T. cruzi DTU identified in chronic Chagas disease Brazilian patients (92.9%) with either cardiac, indeterminate or cardiodigestive forms, born at Southeast and Northeast regions. Other DTU found in much less frequency was TcVI (4.8%). TcII was also associated to patients that evolved with heart failure or sudden cardiac arrest, the two most common and ominous consequences of the cardiac form of Chagas disease.

Parasite load evaluation by qPCR and blood culture in Chagas disease and HIV co-infected patients under antiretroviral therapy

“…It was not possible to differentiate the subgroups TcV from TcVI. The patients who have the samples genotyped were from the Southeastern Brazil (states of São Paulo and Minas Gerais), confirming the prevalence of subtype TcII [ 18 , 23 ]. These patients present the clinical forms undetermined, cardiac or mixed (i.e.…”

“…In reports from the literature, blood culture for T . cruzi presented sensitivity ranging 38%–53% in patients with Chagas disease [ 18 , 19 ]. In this study, the blood culture positivity was 44% (8/18), being within the range reported by other authors.…”

Past and future of trypanosomatids high-throughput phenotypic screening

“… 7 This variability has been associated with factors related to both host and parasite. 8 One possible explanation may be derived from parasites’ genetic background. These parasites show a high genetic variability being assembled into seven distinct genetic groups, or discrete typing units (DTU): TcI-VI and TcBat.…”

“… 9 All of them can infect humans and their frequency varies depending on the geographic location. 8 , 9 The link between T. cruzi genotype and the clinical manifestations (or drug susceptibility) of Chagas disease has been proposed but has not been proved yet. 6 , 7 , 9 So far, there is no vaccine available and only two drugs, benznidazole ( 1 ) and nifurtimox ( 2 ), are clinically used.…”

Letters to the Editor: Indeterminate form of Chagas Disease: some immunological insights

“…Another relevant aspect of this discussion is the fact that only through prospective studies, where long-term follow-up of individuals is carried out, it is possible to correlate the findings with the clinical forms of the disease 5 , 6 . Cross-sectional studies do not allow us to infer cause-effect relationships, but plausible hypotheses may be raised.…”