Twenty-five years of Fio-Chagas contributions to Chagas disease serology: from recombinant antigens to point-of-care diagnosis

Providing reliable, affordable, and field-adapted diagnostic tests remains a principal bottleneck in the control of Chagas disease, whose conventional algorithm requires two serological assays performed in laboratories often distant from the populations most affected. Over the past 25 years, the Fiocruz Translational Research Programme on Chagas Disease (Fio-Chagas) has worked to convert basic discoveries on Trypanosoma cruzi antigens into diagnostic products for the Brazilian Unified Health System (SUS) and other endemic settings. This review traces that trajectory from the cloning of the cytoplasmic (CRA) and flagellar (FRA) repetitive antigens in the late 1980s, through the EIE-Recombinant-Chagas-Bio-Manguinhos ELISA, to the design, production, and validation of the IBMP multi-epitope chimeric antigens (IBMP-8.1 to IBMP-8.4). These molecules were evaluated across analytical, clinical, and operational phases in indirect ELISA, liquid microarray, Western blot, double-antigen sandwich ELISA, biosensors, and lateral flow platforms, using panels from endemic and non-endemic regions, blood banks, post-treatment cohorts, and canine reservoirs. The evidence supports IBMP-8.1 and IBMP-8.4 as the molecular basis of the TR Chagas Bio-Manguinhos rapid test, now implemented in primary care within the Oxente Chagas Bahia Project, illustrating how a sustained translational network has reshaped serological diagnosis of chronic Chagas disease in Brazil under a One Health perspective.