ABSTRACT
Abstract: Background: Chagas disease is an endemic illness in the Americas and therefore constitutes a public health problem. An estimated 8 million people are infected and over 20 million live in areas at risk. In Mexico, the problem is under reported and no epidemiological data by the different States indicating true prevalence for this infection is available. During the chronic phase, 30% of infected patients may develop chagasic cardiomyopathy (CCM), characterized by different types of alterations of cardiac function. Objective: To describe cardiac abnormalities in Trypanosoma cruzi seropositive subjects in the endemic areas. Material and methods: This is a descriptive cross-sectional study with non-random sampling. In our project the endemic area was considered for Trypanosoma cruzi using the Epi Info statistical program (Stat Calc) to calculate the number of subjects to study by means of a sample of 1 033 subjects aged 2-90 years. Prior informed consent or parental consent, implementation of a survey, a 5 mL of blood sample free from anticoagulant was taken from the cubital vein to detect anti-Trypanosoma cruzi by ELISA, recombinant ELISA, hemagglutination indirect (HAI), indirect immunofluorescence (IFI) and Western blot (using the enzyme superoxide dismutase iron as antigen). Those subjects who were positive in two or more tests were chosen for electrocardiogram (EKG) and an echocardiogram (ECO) with portable devices. Results: Of the 1 033 participants, 84 between 6 and 88 years tested positive for Trypanosoma cruzi. In the analysis of data with echocardiograms and electrocardiograms, 47 subjects over 26 years (56%), presented right bundle branch block or left bundle block (RBBB/LBBB), changes in the diameters of the right ventricle or left ejection fraction accounting of 70%. In subjects under 26 years there were electrocardiographic changes (RBBB/LBBB). Conclusion: 8.13% were seropositive for Trypanosoma cruzi with ventricular conduction system and morphological alterations.
Resumen: Antecedentes: La enfermedad de Chagas es una patología endémica en las Américas, donde representa un problema de salud pública. Se estima que aproximadamente 8 millones de personas están infectadas y 20 millones viven en áreas de riesgo de infectarse. En México el problema está subestimado y se carece de datos epidemiológicos por estado del país que indiquen una prevalencia real de este padecimiento. Durante la fase crónica, el 30% de los pacientes infectados pueden desarrollar miocardiopatía chagásica (MCC), que se caracteriza por presentar diferentes alteraciones de la función cardiaca. Objetivo: Describir las alteraciones cardiacas en sujetos seropositivos para Trypanosoma cruzi de áreas endémicas. Material y métodos: Es un estudio con diseño transversal descriptivo, con muestra no probabilística. En nuestro proyecto, se consideró una zona endémica a Trypanosoma cruzi, mediante el programa estadístico Epi Info (Stat Calc), para estimar el número de sujetos a estudiar, obteniéndose una muestra de 1 033 sujetos de edades entre 2 a 90 años. Previo consentimiento informado, y aplicación de una encuesta, se puncionó la vena cubital, obteniéndose una muestra sanguínea de 5 mL, sin anticoagulante, para buscar anticuerpos anti-Trypanosoma cruzi mediante, ELISA, ELISA recombinante, hemaglutinación indirecta (HAI), inmunofluorescencia indirecta (IFI) y Western-Blot (usando la enzima superóxido dismutasa de hierro como antígeno). Los sujetos reactivos a dos o más pruebas fueron seleccionados para la realización de un electrocardiograma (EKG) y un ecocardiograma (ECO) con equipos portátiles Resultados: De los 1 033 participantes, 84 entre 6 a 88 años resultaron positivos para Trypanosoma cruzi. En el análisis de los hallazgos ecocardiográficos y electrocardiográficos en los 47 sujetos mayores de 26 años (56%) presentaron bloqueo de rama derecha o izquierda del haz de His (BRDHH/BRIHH). Conclusión: El 8.13% fueron seropositivos para Trypanosoma cruzi con cambios morfológicos ventriculares y del sistema de conducción del haz de His.
ABSTRACT
Immunological diagnostic methods for Trypanosoma cruzi depend specifically on the presence of antibodies and parasitological methods lack sensitivity during the chronic and “indeterminate” stages of the disease. This study performed a serological survey of 1,033 subjects from 52 rural communities in 12 of the 18 municipalities in the state of Querétaro, Mexico. We detected anti-T. cruzi antibodies using the following tests: indirect haemagglutination assay (IHA), indirect immunofluorescence assay (IFA), ELISA and recombinant ELISA (rELISA). We also performed Western blot (WB) analysis using iron superoxide dismutase (FeSOD), a detoxifying enzyme excreted by the parasite, as the antigen. Positive test results were distributed as follows: ELISA 8%, rELISA 6.2%, IFA and IHA 5.4% in both cases and FeSOD 8%. A comparative study of the five tests was undertaken. Sensitivity levels, specificity, positive and negative predictive values, concordance percentage and kappa index were considered. Living with animals, trips to other communities, gender, age, type of housing and symptomatology at the time of the survey were statistically analysed using SPSS software v.11.5. Detection of the FeSOD enzyme that was secreted by the parasite and used as an antigenic fraction in WBs showed a 100% correlation with traditional ELISA tests.