Severity of Chagasic Cardiomyopathy Is Associated With Response to a Novel Rapid Diagnostic Test for Trypanosoma cruzi TcII/V/VI.

Background: Trypanosoma cruzi causes Chagas disease in the Americas. The outcome of infection ranges from lifelong asymptomatic status to severe disease. Relationship between T. cruzi lineage (TcI-TcVI) infection history and prognosis is not understood. We previously described peptide-based lineage-specific enzyme-linked immunosorbent assay (ELISA) with trypomastigote small surface antigen (TSSA). Methods: A novel rapid diagnostic test (RDT; Chagas Sero K-SeT) that incorporates a peptide that corresponds to the TSSA II/V/VI common epitope was developed and validated by comparison with ELISA. Patients from Bolivia and Peru, including individuals with varying cardiac pathology, and matched mothers and neonates, were then tested using Chagas Sero K-SeT. Results: Chagas Sero K-SeT and ELISA results, with a Bolivian subset of cardiac patients, mothers, and neonates, were in accord. In adult chronic infections (n = 121), comparison of severity class A (no evidence of Chagas cardiomyopathy) with class B (electrocardiogram suggestive of Chagas cardiomyopathy) and class C/D (decreased left ventricular ejection fraction; moderate/severe Chagas cardiomyopathy) revealed a statistically significant increase in Chagas Sero K-SeT reactivity with increasing severity (χ2 for trend, 7.39; P = .007). In Peru, Chagas Sero K-SeT detected the sporadic TcII/V/VI infections. Conclusions: We developed a low cost RDT that can replace ELISA for identification of TSSA II/V/VI immunoglobulin G. Most importantly, we show that response to this RDT is associated with severity of Chagas cardiomyopathy and thus may have prognostic value. Repeated challenge with T. cruzi infection may both exacerbate disease progression and boost the immune response to the TSSApep-II/V/VI epitope.

Clinical validation of a western blot assay for congenital toxoplasmosis and newborn screening in a hospital in Armenia (Quindio) Colombia.

Congenital Toxoplasma infection can only be discovered or prevented by the appropriate serological screening and subsequent treatment of the mother and her offspring. In Colombia, there is no obligatory Toxoplasma screening for pregnant women and both the reporting and follow-up of congenital toxoplasmosis cases is limited, thereby is a public health problem that have no been addressed by health authorities. The aim of this study was to investigate the occurrence of congenital toxoplasmosis in a public hospital from Armenia, Colombia. A total of 200 serum samples of cord blood were collected. We applied a western blot assay (ID Blot DPC Diagnostics, US) for Toxoplasma IgG, IgM and IgA antibodies that was validated in a cohort of children with confirmed presence or absence of congenital infection. The sensitivity of western blot assay was 91 per cent and the specificity was 100 per cent. In the cord blood samples, we found one infected child that died at day 4 of life and his infection was confirmed by PCR of the B1 specific Toxoplasma gene on brain biopsy. This results show a high prevalence (0.5 per cent, IC95 per cent 0.2-0.8) of Toxoplasma infection in Colombian newborns. Thus, we recommend additional studies to determine the cost-effectiveness of a newborn screening program for congenital toxoplasmosis in other settings in Colombia.