Spatial and spatiotemporal analysis of leprosy occurrence in a hyperendemic state in northeastern Brazil: an ecological study

Leprosy, caused by Mycobacterium leprae, remains a public health challenge in Brazil, characterized by persistent transmission, physical disabilities, and a strong association with social inequalities. This study aimed to describe the sociodemographic and clinical profile of cases, analyze temporal trends, and identify spatial and spatiotemporal patterns from 2001 to 2024. Spatial distribution was analyzed using maps of crude rates and rates smoothed by the Local Empirical Bayesian Estimator. Temporal trends were assessed across four periods (2001-2024). Spatial dependence and clustering were identified using global and local Moran’s indices, with a 5% significance level. This is an ecological study with time-series and spatial analyses, including 91,138 new cases reported in the Notifiable Diseases Information System and demographic data from the Brazilian Institute of Geography and Statistics. A predominance was observed among males (56.9%), young adults aged 15-29 years (24.8%), individuals of mixed race ethnicity (58.4%), and those with low educational attainment (51.5%), with a higher frequency of multibacillary (65.8%) and borderline (42.7%) forms. Spatial analysis revealed persistent hyperendemic areas in the northern, northeastern, and eastern regions of the state, as well as active transmission foci among individuals under 15 years of age. Spatiotemporal scan analysis identified high-risk clusters in the central region (2006-2015; RR = 2.24) and in the São Luís metropolitan area (2010-2019; RR = 1.77). In conclusion, leprosy maintains a high burden in Maranhão, requiring strengthened primary health care, expanded active case finding, and the integration of spatial analyses into surveillance, alongside intersectoral policies aimed at reducing social inequalities.