Spatial and spatiotemporal distribution of Schistosoma mansoni cases in the state of Alagoas, Brazil

Abstract

This study aimed to analyze the occurrence of Schistosoma mansoni in the State of Alagoas, Brazil, over space and time from 2012 to 2021. An ecological, quantitative, and spatiotemporal study was conducted using secondary data from the Schistosomiasis Control and Surveillance System (SISPCE/DATASUS). Data were aggregated by health regions (HR) and municipalities. During the study period, 1,466,100 examinations were performed, and 73,325 cases of schistosomiasis were diagnosed. Spatial analysis showed that 20 municipalities had moderate positivity rates (5.1 – 15.0%), and one municipality had a high positivity rate above 15.1%. Global Moran’s Index indicated significant positive spatial autocorrelation (I= 0.52308; p= 0.001). The Local Moran’s Index identified 16 municipalities with a high-high pattern, distributed across the 1st, 2nd, 3rd, 4th, and 6th HR. The space-time scan analysis revealed two significant risk clusters. The primary cluster comprised 50 municipalities, predominantly located in the 3rd, 4th, and 6th HR, showing a relative risk (RR) of 11.06 (p< 0.001). The proportion of infections classified as severe was below 1%. These findings highlight the persistence of high-risk areas for schistosomiasis in Alagoas, concentrated in specific health regions, and are aligned with WHO goals to eliminate schistosomiasis as a public health problem.

KEY WORDS: Epidemiology; neglected diseases; public health; Schistosoma mansoni.