Serologic and parasitologic demonstration of Trypanosoma cruzi infections in an urban area of central Mexico: correlation with electrocardiographic alterations.

Trypanosoma cruzi infection in central Mexico has not been fully documented, yet some data suggest its presence. In this work, sera from 211 subjects living in the state of Morelos and at risk of T. cruzi infection due to their living in contact with the vector were analyzed for the presence of antibodies to a total antigen extract of a Mexican isolate of T. cruzi. A seropositivity of 20% was demonstrated by both an enzyme-linked immunosorbent assay and Western blotting. Furthermore, parasites were isolated from five seropositive individuals, and these were genetically characterized as T. cruzi by multilocus enzyme electrophoresis. A case-control electrocardiographic study was conducted that included the seropositive individuals and twice as many seronegative controls living in the same area. A significant correlation was found between seropositivity and electrocardiographic alterations. These findings have important implications for perception of the prevalence of Chagas' disease in Mexico. Moreover, the presence of this disease in rural communities rapidly transforming into urban ones might have important epidemiologic consequences.

Specific immunodiagnosis of Chagas disease: immunodiffusion test using a specific serum anti-Trypanosoma cruzi component 5.

A micro double diffusion test (MD), allowing the identification of precipitation brand 5 by identity reaction, using a rabbit specific anti-component 5 serum, was evaluated for the immunological diagnosis of Chagas' disease. The previous studies on the Trypanosoma cruzi specificity of component 5[g] were completed, showing it to be absent in Leishmania brazilienis, but present in different strains of T. cruzi. 200 sera from Bolivian patients were studied. (88 with a positive xenodiagnosis, 45 with mucocutaneous leishmaniasis but without Chagas' disease, and 67 controls). Band 5 was found in 74 (84.1%) of the sera with positive xenodiagnosis but was never found either in the leishmaniasis or in the control groups. MD, allowing an easy detection of T. cruzi specific band 5, cheap and simple to perform, can be recommended in association with other serological tests, when highly specific immunodiagnosis of Chagas' disease is required.

Specific and sensitive immunological diagnosis of Chagas' disease by competitive antibody enzyme immunoassay using a Trypanosoma cruzi-specific monoclonal antibody.

Coexistence of Chagas' disease with leishmaniasis and T. rangeli infection in endemic areas and cross-reactivity between corresponding etiological agents can confuse the immunodiagnosis of Chagas' disease. A discriminative serological test could therefore represent a major advance in specific immunodiagnosis. A competitive antibody enzyme immunoassay against a component 5-enriched preparation, using a T. cruzi species-specific monoclonal antibody has allowed development of a specific serodiagnosis of Chagas' disease with high sensitivity (96.6% in undetermined and chronic phases of infection). This test can differentiate Chagas' disease from other cross-reacting parasitic diseases in areas where concomitant infections are unknown or suspected.