ABSTRACT
A survey was carried out on 1487 individuals to assess the seroprevalence of Trypanosoma cruzi infection in French Guiana. The overall prevalence of T. cruzi specific IgG was 0.5 percent. In multivariate analysis, residence in areas where housing is favorable for the presence of triatomine bugs was the only factor associated with the presence of T. cruzi antibodies. These results have implications for public health since blood donors are not routinely screened for T. cruzi infection in French Guiana.
Subject(s)
Humans , Animals , Male , Female , Child , Adolescent , Adult , Antibodies, Protozoan , Chagas Disease , Immunoglobulin G , Trypanosoma cruzi , Cross-Sectional Studies , French Guiana , Multivariate Analysis , Prevalence , Retrospective Studies , Seroepidemiologic StudiesABSTRACT
A cross section of a human population (501 individuals) selected at random, and living in a Bolivian community, highly endemic for Chagas disease, was investigated combining together clinical, parasitological and molecular approaches. Conventional serology and polymerase chain reaction (PCR) indicated an active transmission of the infection, a high seroprevalence (43.3 percent) ranging from around 12 percent in < 5 years to 94.7 percent in > 45 years, and a high sensitivity (83.8 percent) and specificity of PCR. Abnormal ECG tracing was predominant in chagasic patients and was already present among individuals younger than 13 years. SAPA (shed acute phase antigen) recombinant protein and the synthetic peptide R-13 were used as antigens in ELISA tests. The reactivity of SAPA was strongly associated to Trypanosoma cruzi infection and independent of the age of the patients but was not suitable neither for universal serodiagnosis nor for discrimination of specific phases of Chagas infection. Anti-R-13 response was observed in 27.5 percent only in chagasic patients. Moreover, anti-R13 reactivity was associated with early infection and not to cardiac pathology. This result questioned previous studies, which considered the anti-R-13 response as a marker of chronic Chagas heart disease. The major clonets 20 and 39 (belonging to Trypanosoma cruzi I and T. cruzi II respectively) which circulate in equal proportions in vectors of the studied area, were identified in patients' blood by PCR. Clonet 39 was selected over clonet 20 in the circulation whatever the age of the patient. The only factor related to strain detected in patients' blood, was the anti-R-13 reactivity: 37 percent of the patients infected by clonet 39 (94 cases) had anti-R13 antibodies contrasting with only 6 percent of the patients without clonet 39 (16 cases)
Subject(s)
Humans , Male , Female , Child, Preschool , Child , Adolescent , Adult , Chagas Disease , Trypanosoma cruzi , Acute Disease , Antibodies, Protozoan , Bolivia , Chagas Disease , Chronic Disease , Cloning, Molecular , Cross-Sectional Studies , Endemic Diseases , Insect Vectors , Prevalence , Sensitivity and Specificity , Seroepidemiologic Studies , Serologic Tests , Trypanosoma cruziABSTRACT
Con el fin de encontrar mejores antigenos de T. cruzi y posibles marcadores inmunologics, para el diagnostico de las diferentes formas clinicas del mal de chagas, se provaron amastigotes y la fraccion microsomal de epimastigotes de T. cruzi. Se utilizaron tambien clonesrecombinantes (jL5, jL7, jL8) y un peptido sintetico R-13, que compromete 13 residuos C-terminales del recombinante jL5. La habilidad de los anticuerpos, en sueros de individuos con enfermedad de chagas cronica para reaccionar con diferentes antigenos, varia de acuerdo al estado clinico del paciente. Los resultados señalan que los niveles de anticuerpos IgA-anti amastigotes de T. cruzi, son significativos para los pacientes con afeccion digestiva; contrariamnete anticuerpos de pacientes con cardiopatia, fueron predominantemente dirigidos contra la fraccion microsoma, recombinante jL5 y peptido R-13. En conclusion , los resultados del presente trabajo, indican que la forma digestiva del mal de chagas puede ser difinida por la respuesta IgA-antiamastigote, mientras que las formas cardiacas son mejor determinadas por las respuestas IgA antimicrosomal o anti-R13. .