Clinical use of molecular methods for Trypanosoma cruzi infection in endemic and non-endemic countries: Benefits, limitations and challenges

Abstract

Trypanosoma cruzi infection is diagnosed by parasitological, molecular, and serological tests. Molecular methods based on DNA amplification provide a more sensitive alternative to classical parasitological techniques for detecting evidence of T. cruzi parasitemia, and are the preferred tests for congenital and oral transmission cases and parasite reactivation in chronically infected immunosuppressed individuals. In newborns at risk of vertical transmission, simplified diagnostic algorithms that provide timely results can reduce the high follow-up losses observed with current algorithms. Molecular methods have also proved useful for monitoring T. cruzi infection in solid organ transplantation recipients, regardless of host immune status, allowing parasite detection even before symptom manifestation. Furthermore, in the absence of other biomarkers and a practical test of cure, and given the limitations of serological methods, recent clinical guidelines have included polymerase chain reaction (PCR) to detect therapeutic failure after antiparasitic treatment in chronically infected adults. Increasing evidence supports the use of molecular tests in a clinical context, given the improved sensitivity and specificity of current assays – characteristics which largely depend on epidemiological factors and genetic and antigenic variability among T. cruzi strains. Further development and registration of commercial PCR kits will improve the use of molecular tests. We discuss the attributes of PCR and other molecular tests for clinical management in people with T. cruzi infection.

In vitro diagnostic methods of Chagas disease in the clinical laboratory: a scoping review

“…Common PCR targets for T. cruzi include repeat tandem sequence of nuclear DNA or nuclear satellite DNA (stDNA) of DNA sequence E13 and kinetoplast DNA (kDNA; Ramírez et al, 2009 ; Brasil et al, 2010 ). Molecular testing also aids in treatment response monitoring, allowing genotypic characterization by identifying DTUs, revealing geographical distribution ( Pinazo et al, 2023 ). However, no clear association exists between DTUs and clinical outcomes or transmission cycles ( Velásquez-Ortiz and Ramírez, 2020 ; Barnabé et al, 2023 ; Pinazo et al, 2023 ).…”

“…Molecular testing also aids in treatment response monitoring, allowing genotypic characterization by identifying DTUs, revealing geographical distribution ( Pinazo et al, 2023 ). However, no clear association exists between DTUs and clinical outcomes or transmission cycles ( Velásquez-Ortiz and Ramírez, 2020 ; Barnabé et al, 2023 ; Pinazo et al, 2023 ).…”

“…The COVID-19 pandemic changed the landscape for PCR testing, allowing more facilities to perform PCR testing ( Pascual-Vázquez et al, 2023 ; Pinazo et al, 2023 ). Moreover, the repurposing of PCR platforms used for COVID-19 testing provides an opportunity for centers to testing other for pathogens, including T. cruzi .…”

“…The DTUs range from TcI to TcVI, and Tcbat. These confer high genetic and phenotypic diversity which may translate into different clinical presentation and severity, treatment, immune response and ultimately to serological response ( Pinazo et al, 2023 ).…”

“…Direct parasitological methods are reserved for specific scenarios. Molecular tests are preferred in the acute phase, congenital and oral transmission, and in chronic reactivation following immunosuppression ( Ramírez et al, 2009 ; Hernández et al, 2016 ; Nunes et al, 2018 ; Hochberg et al, 2021 ; Forsyth et al, 2022 ; Pascual-Vázquez et al, 2023 ; Pinazo et al, 2023 ). Classical direct parasitological tests can be useful as well.…”