Abstract INTRODUCTION: Congenital transmission (CT) of Trypanosoma cruzi has led to globalization of Chagas disease and its growing relevance as a public health problem. Although the occurrence of CT has been associated with several factors, its mechanisms are still unknown. This study aimed to analyze the geographical and familiar variables of mothers and their association with CT of Chagas disease in a population living in non-endemic areas of Argentina for the last decades. METHODS: We developed a retrospective cohort study in a sample of 2120 mother-child pairs who attended three reference centers in the cities of Buenos Aires, Santa Fe, and Salta between 2002 and 2015. RESULTS: The highest CT rates were observed in children born to Argentinean mothers (10.7%) and in children born to mothers from Buenos Aires (11.7%). Considering the areas of origin of the mothers, those from areas of null-low risk for vector-borne infection had higher CT rates than those from areas of medium-high risk (11.1% vs 8.2%). We also observed a significant intra-familiar “cluster effect,” with CT rates of 35.9% in children with an infected sibling, compared to 8.2% in children without infected siblings (RR=4.4 95% CI 2.3-8.4). CONCLUSIONS: The associations observed suggest a higher CT rate in children born to mothers who acquired the infection congenitally, with familiar antecedents, and from areas without the presence of vectors. These observations are considered new epidemiological evidence about Chagas disease in a contemporary urban population, which may contribute to the study of CT and may also be an interesting finding for healthcare professionals.

In Argentina, around 1500 children are born each year with Trypanosoma cruzi infection. Mother-to-child transmission is the main source of new cases of Chagas disease and of its occurrence in non-endemic areas. Our objective was to survey the information available on congenital T. cruzi infection, to analyze its evolution and its relation with the index of maternal infection and the risk for vector-borne infection by province of Argentina. Data concerning the public health sector for the period 1997-2014 were retrieved from national and local records. An increase in the number and proportion of pregnant women examined for Chagas was observed, reaching 60.3% coverage in 2014. The prevalence of maternal infection dropped from 9.0% to 2.6%. The control of newborns from infected women was highly variable (23.3%-93.6%), and data quality was deficient, varying amply by province and year. The rate of congenital infection had an irregular evolution and its national average fluctuated between 1.9 and 8.2%. An association was observed between the risk for vector-borne infection and the prevalence of maternal infection by province (Wilcoxon test p = 0.017). The rate of congenital transmission by province was neither associated with the rate of maternal infection (linear regression p = 0.686) nor with the risk for vectorial infection (Kruskal-Wallis test p = 0.3154). The available data show insufficient control of children born from infected mothers, as well as deficient recording of these procedures. Both aspects must be improved to achieve better epidemiological information and to enable timely access of infected children to treatment.

En Argentina nacen alrededor de 1500 niños por año con infección por Trypanosoma cruzi. La transmisión vertical es la principal vía de generación de nuevos casos de Chagas, y de su presencia en zonas no endémicas. Nuestro objetivo fue relevar datos disponibles sobre infección congénita por T. cruzi, analizar su evolución y relación con indicadores de prevalencia materna y riesgo vectorial por regiones de Argentina. Se investigaron fuentes oficiales y bibliografía científica. Se obtuvieron datos nacionales y provinciales del período 1997-2014 del subsector público de salud. Se observó un aumento de embarazadas controladas, que alcanzó una cobertura del 60.3% en 2014. La prevalencia de infección materna descendió de 9.0% a 2.6%. El control en hijos de mujeres infectadas fue variable (entre 23.3% y 93.6% de los niños en riesgo) y la calidad del dato fue deficiente según provincia y año. La tasa de transmisión congénita tuvo una evolución irregular y, según un indicador corregido, la tasa media nacional fluctuó entre 1.9 y 8.2%. Se observó asociación entre la prevalencia materna y el riesgo vectorial en las provincias (test Wilcoxon p = 0.017). La tasa de transmisión congénita provincial no mostró relación con la tasa de infección materna (regresión lineal p = 0.686) ni con el nivel de riesgo vectorial (test Kruskal-Wallis p = 0.3154). Los datos disponibles muestran una deficiencia en los controles de hijos de madres infectadas y de su notificación en el período analizado. Deben mejorar ambos aspectos para obtener información epidemiológica fiable y permitir el acceso oportuno de los niños infectados al tratamiento.