Diagnostic assay for congenital Chagas disease

Project Summary This project aims to develop a diagnostic test for congenital Chagas disease (cCD), caused when infection with the protozoan Trypanosoma cruzi is passed from mother to fetus during pregnancy. Chagas disease is the parasitic disease with the highest burden in the Western hemisphere, yet the need remains for accurate and accessible diagnostics. This is particularly true for congenital transmission of the infection, as treatment in infants is much more effective and well-tolerated than in chronic adult infections. However, the current diagnostic standard for infants with a risk of congenital Chagas remains microscopy, which is highly subjective and misses a large percentage of infections, and IgG testing at 8-9 months after birth, which results in an enormous loss to follow up. A diagnostic assay targeting anti-T. cruzi IgM would meet the need for an accurate and accessible point-of-delivery test and enable cost-saving, widespread screening of newborns. Two versions of a test for cCD based on IgM detection will be developed, the best performing of which will be advanced in Phase II: (1) an IgM Western blot based on native Trypomastigote Excreted/Secreted Antigen (TESA) and (2) a peptide IgM ELISA based on Shed Acute-Phase Antigen (SAPA). Both tests will address the need for batch-to-batch and laboratory- to-laboratory consistency in antigens used and will produce a result in approximately three hours. Panels of well- characterized congenital Chagas samples and controls, including cross-reactive samples from other parasitic infections, will be used to optimize both versions of the test as well as determine initial sensitivity and specificity of each assay format. One major hurdle to commercialization of Western blot-based methods is the difficulty in interpreting test results. As it is widely recognized that mobile phone technology provides an opportunity to address such diagnostic challenges, this technology will be leveraged to standardize Western blot interpretation through development of a prototype smartphone application that can perform automated blot analysis. A machine-learning algorithm will be implemented for this purpose to interpret IgM Western blot band patterns, removing the need for subjective human interpretation. The successful completion of Phase I objectives will demonstrate the feasibility of an IgM diagnostic test for congenital Chagas disease which can be scaled to manufacturing in Phase II and will address a recognized global and public health priority.