Introduction
Chagas disease
AMERICAN TRYPANOSOMIASIS, DISEASE, PARASITIC DISEASE, CHAGAS DISEASE
Chagas disease (American trypanosomiasis) is a potentially life-threatening parasitic disease that for many years has been endemic in 21 Latin American countries and areas of southern USA [The protozoan The diagnostics recommended by national organizations and the Pan American Health Organization (PAHO) includes the combining of two positive serological tests: enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination assay (IHA) or indirect immunofluorescent assay (IFA), with potentially a third test if the results are conflicting [Potential biomarkers of early therapeutic responses have been tested in different clinical contexts. An ELISA using a 29 kDa flagellar recombinant F29 antigen of the parasite (ELISA F29) was developed [In a prospective, historically controlled, phase 3 clinical trial, the CHagas disease In Children treated with nifurtimOx follow-up for SEroconversion and CURE (CHICO and CHICO SECURE) trial, we followed pediatric patients with Chagas disease over a period of 4 years after treatment with a new formulation of nifurtimox and evaluated the incidence rate of seronegative conversion and their serological response to nifurtimox treatment using conventional serological methods (recombinant ELISA, total purified antigen ELISA, and IHA) and ELISA F29 at annual follow-ups. The progress of seronegative conversion detected by ELISA F29 and conventional serological methods during follow-up was compared. The results obtained for conventional serology, parasitological tests, and safety, as well as for ELISA F29 at first year of follow-up, are reported elsewhere [