Parasitological, serological and molecular diagnosis of acute and chronic Chagas disease: from field to laboratory

There is no consensus on the diagnostic algorithms for many scenarios of Trypanosoma cruzi infection, which hinders the establishment of governmental guidelines in endemic and non-endemic countries. In the acute phase, parasitological methods are currently employed, and standardised surrogate molecular tests are being introduced to provide higher sensitivity and less operator-dependence. In the chronic phase, IgG-based serological assays are currently used, but if a single assay does not reach the required accuracy, PAHO/WHO recommends at least two immunological tests with different technical principles. Specific algorithms are applied to diagnose congenital infection, screen blood and organ donors or conduct epidemiological surveys. Detecting Chagas disease reactivation in immunosuppressed individuals is an area of increasing interest. Due to its neglect, enhancing access to diagnosis of patients at risk of suffering T. cruzi infection should be a priority at national and regional levels.

Serological based monitoring of a cohort of patients with chronic Chagas disease treated with benznidazole in a highly endemic area of northern Argentina

This study aimed to evaluate well-documented diagnostic antigens, named B13, 1F8 and JL7 recombinant proteins, as potential markers of seroconversion in treated chagasic patients. Prospective study, involving 203 patients treated with benznidazole, was conducted from endemic areas of northern Argentina. Follow-up was possible in 107 out of them and blood samples were taken for serology and PCR assays before and 2, 3, 6, 12, 24 and 36 months after treatment initiation. Reactivity against Trypanosoma cruzi lysate and recombinant antigens was measured by ELISA. The rate of decrease of antibody titers showed nonlinear kinetics with an abrupt drop within the first three months after initiation of treatment for all studied antigens, followed by a plateau displaying a low decay until the end of follow-up. At this point, anti-B13, anti-1F8 and anti-JL7 titers were relatively close to the cut-off line, while anti-T. cruzi antibodies still remained positive. At baseline, 60.8% (45/74) of analysed patients tested positive for parasite DNA by PCR and during the follow-up period in 34 out of 45 positive samples (75.5%) could not be detected T. cruzi DNA. Our results suggest that these antigens might be useful as early markers for monitoring antiparasitic treatment in chronic Chagas disease.

Nuevas experiencias para comprender la complejidad / New experiences to understand complexity

La transformación de la relación de los ciudadanos con la ciencia y la tecnología inducida por la importancia inédita de las innovaciones científicas y técnicas en la sociedad contemporanea, constituye un verdadero desafío para los centros y museos científicos en tanto que canales de mediación de la apropiación social de la ciencia. Estos se ven confrontados a la necesidad de adaptarse e innovar con respecto a los modelos clásicos de presentación para tomar en cuenta la complejidad del mundo contemporaneo, e integrar cada vez más la actualidad científica y los grandes interrogantes de nuestro tiempo en las realizaciones y modo de expresión museísticos. Surgen así nuevas experiencias, donde la evolución técnica de los modos de mediación se combina con la integración de los contenidos científicos y técnicos en una perspectiva y una problemática social. Esta reflexión cubre igualmente el campo de la colaboración entre instituciones, a partir del ejemplo de experiencias realizadas por la Cité des Sciences et de l'Industrie en relación con establecimientos y programas de difusión de la ciencia y la técnica en diferentes países de América Latina