Background Chagas disease (caused by Trypanosoma cruzi infection) evolves to chronic chagasic cardiomyopathy (CCC) affecting 1.8 million people worldwide. This is the first randomized, placebo-controlled, double-blinded, clinical trial designed to estimate efficacy and safety of selenium (Se) treatment in CCC. Methods 66 patients with CCC stages B1 (left ventricular ejection fraction [LVEF] > 45% and no heart failure; n = 54) or B2 (LVEF < 45% and no heart failure; n = 12) were randomly assigned to receive 100 mcg/day sodium selenite ( Se, n = 32) or placebo ( Pla, n = 34) for one year (study period: May 2014-September 2018). LVEF changes over time and adverse effects were investigated. Trial registration number: NCT00875173 (clinicaltrials.gov). Findings No significant differences between the two groups were observed for the primary outcome: mean LVEF after 6 (β = +1.1 p = 0.51 for Se vs Pla ) and 12 months (β = +2.1; p = 0.23). In a subgroup analysis, statistically significant longitudinal changes were observed for mean LVEF in the stage B2 subgroup (β= +10.1; p = 0.02 for Se [ n = 4] vs Pla [ n = 8]). Se treatment was safe for CCC patients, and the few adverse effects observed were similarly distributed across the two groups. Interpretation Se treatment did not improve cardiac function (evaluated from LVEF) in CCC. However, in the subgroup of patients at B2 stage, a potential beneficial influence of Se was observed. Complementary studies are necessary to explore diverse Se dose and/or associations in different CCC stages (B2 and C), as well as in A and B1 stages with longer follow-up. Funding Brazilian Ministry of Health, Fiocruz, CNPq, FAPERJ.

In the absence of validated biomarkers to control the cure of Chagas disease, PCR-based diagnosis is being used as the main tool for an early indication of therapeutic failure. However, since it is considered a technique of complex reproducibility, mainly due to difficulties in establishing accurate controls to guarantee the quality of the reaction, the use of PCR for Chagas disease diagnosis is restricted to specialized centers. In an effort to disseminate the molecular diagnosis of Chagas disease and its applications, new diagnostic kits based on qPCR have been made available in the market in recent years. Here, we show the results of the validation of the NAT Chagas kit (Nucleic Acid Test for Chagas Disease) for the detection and quantification of T. cruzi in blood samples of patients suspected of Chagas disease infection. The kit, composed of a TaqMan duplex reaction targeting the T. cruzi satellite nuclear DNA and an exogenous internal amplification control, presented a reportable range from 104 to 0.5 parasite equivalents/mL and a limit of detection (LOD) of 0.16 parasite equivalents/mL of blood. In addition, the NAT Chagas kit detected T. cruzi belonging to all six discrete typing units (DTUs—TcI to TcVI), similarly to the in-house real-time PCR performed with commercial reagents, which has been selected as the best performance assay in the international consensus for the validation of qPCR for Chagas disease. In the clinical validation presented here, the kit showed 100% sensitivity and 100% specificity when compared to the consensus in-house real-time PCR assay. Thus, the NAT Chagas kit, which is produced entirely in Brazil under the international standards of good manufacturing practices (GMP), appears as an excellent alternative to enable the molecular diagnosis of Chagas disease in public and private diagnostic centers, as well as to facilitate the monitoring of patients under etiological treatment participating in clinical trials.

Objectives: The development and production of viral vaccines involves several steps that need the monitoring of viral load throughout the process (antigen production, purification, inactivation). Currently, these steps are monitored by plaque lysis titration assay, whose results take about seven to ten days to come out. With the advent of real time RT-PCR, we have a faster approach available to this issue. In this context, the development, standardization and validation of a technique to quickly and efficiently quantify the yellow fever (YF) virus in the aforementioned stages is extremely important. Methods: To accomplish that, we constructed a plasmidial standard curve and validation parameters were evaluated. Furthermore, we defined the limits of detection and quantification of the test. To ensure high quality, internal controls were established in order to avoid false negative results. Results: The statistical analysis revealed an excellent correlation between the results obtained in RNA copies/mL quantified by qRT-PCR and the viral titer calculated by lysis plaques tests (R=0.96). In addition, a correlation factor for conversion of the real time PCR data to plaque assays was generated. The results analysis showed that the validation experiments sufficed all parameters defined by the quality control sector. Conclusion: The technique herein standardized proved to be effective for determining YF viral load both in vivo and in vitro, thus becoming a very important tool in all projects developed in LATEV, and may eventually be adopted as the gold standard laboratory analysis and quality control for vaccine production.