Prevalencia de la enfermedad de Chagas en donantes y en mujeres embarazadas procedentes de Latinoamérica: estudio epidemiológico

El objetivo de la tesis fue conocer la prevalencia de la enfe5rmedad de Chagas en población de riesgo de ambos sexos procedentes de Latinoamérica y la incidencia de la transmisión vertical (Chagas congénito en los bebés nacidos de mujeres diagnosticadas durante el periodo de estudio. Se diseñó un estudio epidemiológico transversal, descriptivo, con dos cohortes poblacionales (donantes de sangre y mujeres embarazadas) y dos fases temporales, una prospectiva (2006-2010) y otra retrospectiva (2011-2015. Los datos demográficos básicos y los resultados sobre el diagnóstico de la enfermedad de Chagas fueron facilitados por los laboratorios de los centros participantes en el estudio (Centro de transfusión de la Comunidad Valenciana y los Departamentos de Salud Valencia-Hospital Generaly Valencia Clínico-Malvarrosa). Se realizó el análisis estadístico de los resultados, considerando como variables principales a las cohortes de población y los resultados de la prevalencia de la enfermedad de Chagas y como covariables los datos demográficos y las observaciones obtenidas en las encuestas en las encuestas realizadas en la fase prospectiva. Se estudiaron muestras de 43.140 adultos (26.612 hombres y 16.528 mujeres), en su mayoría latinoamericanos (99,5%). La prevalencia global fue del 1,55, siendo más alta en las mujeres (1,1%) que en los hombres (0,35%) (X2 = 398,42 p de 30 años ( p < 0,001) independientemente de su origen. La comparación de las prevalencias de la fase prospectiva de ambas cohortes demostró que la enfermedad es más frecuente en las mujeres embarazadas que en los donantes de sangre (X2 = 428,2p < 0.001). El análisis de las covariables permitió constatar la existencia de asociaciones significativas entre los hechos de haber vivido en medio rural (X2 = 16,56 p < 0.00005), en viviendas precarias tipo ranchito chagásico (X2 = 13,77 p < 0.00021) y haber recibido transfusiones previas en Latinoamérica (X2 = 46,86 p < 0.001) con la transmisión de Trypanosoma cruzi. Se diagnosticaron 15 casos de infección congénita entre los nacidos de las 411 mujeres embarazadas diagnosticadas de infección por T. cruzi, lo que supone una tasa de incidencia acumulada de transmisión vertical de del 3,6% Los resultados obtenidos demuestran que la enfermedad de Chagas: i)es más prevalente en América Central y en los Países del Cono Sur que en los demás países endémicos . ii) es más prevalente en las mujeres que en los hombres especialmente en la población ≥ 30 años independientemente del sexo . iii) incide significativamente en la población del medio rural que ha vivido en viviendas precarias y en aquellos que han recibido transfusiones de sangre en Latinoamérica.The objective of the thesis was to know the prevalence of Chagas disease in a population at risk of both gendes from Latin America and the incidence of vertical transmission (congenital Chagas) in babies born to women diagnosed during the study period. A descriptive cross-sectional, epidemiological study was designed, with two population cohorts (blood donors and pregnant women) and two temporal phases, one prospective (2006-2010) and the other retrospective (2011-2015). The basic demographic data and the results on the diagnosis of Chagas disease were provided by the laboratories of the centers participating in the study (Transfusion Center of the Valencian Community and the Departments of Health Valencia-Hospital General Valencia Clínico-Malvarrosa). Statistical analysis of the results was carried out, considering as main variables the population cohorts and the results of the prevalence of Chagas disease and demographic data obtained with the surveys carried out in the prospective phase as covariales. Samples of 43,140 adults (26,612 men and 16,528 women), mostly Latin American (99.5%), were studied. The overall prevalence was 1.5%, being higher in women (1.1%) than in men (0.35%) (X2 = 398.42 p<0.001). A significant association was observed between the prevalences of the natives of Central America (3.5%) and the Southern Cone Countries (3.9%) (X2 = 0.282 p<0.5954), compared to those of the other countries. The countries with prevalence rates higher than the global one (1.5%) were five, three from the Southern Cone (Bolivia 11.1%; Paraguay 4.5% and Brazil 1.8%) and two from Central America (Honduras 5, 8% and Nicaragua 3.1%). The blood donors were 39,864 adults (26,612 men and 13,252 women), mostly Latin Americans (99.6%). The detected prevalence was 0.6%, being higher in women (1.1%) than in men (0.3%) (X2 = 91.284 p < 0.001). A significant association was observed between origin from Central America (2.2%) and Chagas disease compared to the other subregions of the Americas except for the countries of the Southern Cone (1.5%) (X2 = 2.084 p < 0.14882). It was shown that Chagas disease is more common in women (57.1%) than in men (42.1%) and that significantly the most affected age group is those between 30 to 39 years (X2 = 109.84 p < 0.001). The countries with prevalence rates higher than the global one (0.6%) were five, three from the Southern Cone (Bolivia 5.3%; Paraguay 1.0% and Chile 0.7%) and two from Central America (Honduras 4.0 % and Nicaragua 2.3%). In the prospective phase of the study, the relationship of the positive cases with the administrative divisions of the countries of origin or residence and the belonging of this variable to the Gran Chaco ecoregion, showed that the countries that comprise it (Argentina, Bolivia, Brazil and Paraguay) are those with the highest prevalence in the study (X2 = 150.08 p < 0.001). Most of the pregnant women were Latin American (98.6% 2,231/3,276). A total of 411 cases were diagnosed, which represents an overall prevalence of 12.5%. Significant differences were observed indicating that Chagas disease is more prevalent in South American women, especially in those from the Southern Cone countries (Southern Cone Countries versus Andean Countries (X2 = 22.99 p < 0.001), than in natives of other Latin American countries and those ≥30 years old (p < 0.001), regardless of their origin. The comparison of the prevalences of the prospective phase of both cohorts showed that the disease is more frequent in pregnant women than in blood donors. blood (X2 = 428.2p < 0.001).The analysis of the covariates allowed us to confirm the existence of significant associations between the facts of having lived in a rural environment (X2 = 16.56 p < 0.00005), in precarious homes such as chagasic ranches ( X2 = 13.77 p < 0.00021) and having received previous transfusions in Latin America (X2 = 46.86 p < 0.001) with transmission of Trypanosoma cruzi. Fifteen cases of congenital infection were diagnosed among the newborns of the 411 pregnant women diagnosed with T. cruzi infection, which represents a cumulative incidence rate of vertical transmission of 3.6%. The results obtained show that Chagas disease: i) is more prevalent in Central America and the Southern Cone Countries than in the other endemic countries. ii) it is more prevalent in women than in men, especially in the population ≥30 years of age, regardless of sex. iii) it has a significant impact on the rural population that has lived in precarious housing and on those who have received blood transfusions in Latin America