Effect of chaotropes in Chagas disease and leishmaniasis cross-reacting serology assays for epidemiological surveys.

Introduction: Serological cross-reactivity between leishmaniasis and Chagas disease, especially at low titers, leads to difficulties of the seroepidemiological interpretation.

Methods: We have studied the ability of urea as a chaotrope to select high-avidity antibodies in IgG ELISA, thus reducing low-avidity IgG cross-reactivity in serologically positive samples in both assays.

Results: Using 0.