RESUMEN
BACKGROUND: Chagas disease constitutes a public health problem, and Spain is the non-endemic country with the highest burden of disease outside the Americas. It represents a model for non-endemic countries regarding health policies to control the disease. This study is aimed to generate estimates of the T.cruzi prevalence and the number of undetected and untreated individuals with the infection in Spain and to compare them with the actual number of cases reported by official sources. METHODS: Using aggregate data collected from the literature and official sources (Spanish National Statistics Institute; Spanish Agency of Medicines and Medical Devices) from 2010 to 2018, this study estimates the number of Chagas disease cases, plus the underdiagnosis and undertreatment rates. RESULTS: We estimated that 55,367 out of 2,602,285 migrants originally from endemic countries were living with Chagas disease in Spain in 2018, accounting for a prevalence of 2.1%. Only 1% of these cases(613/455,566) were children aged 14 years or less resulting in a prevalence of 0.1%. Bolivian migrants accounted for 53.9% of the total estimated cases. The index of underdiagnosis and undertreatment were heterogeneous across different Spanish autonomous regions, but the overall index of underdiagnosis was around 71%, and the overall index of undertreatment was 82.5% in patients aged 15 years or older, and 60% in children. CONCLUSION: The burden of Chagas disease in Spain is considerable. Index of underdiagnosis and undertreatment are high, particularly in women of childbearing age, but they have improved in children since the implementation of antenatal screening programmes.