Spatial analysis, temporal trend, and local risk of congenital syphilis new cases in Sergipe, Brazil

Abstract

The present study aimed to analyze the spatial distribution and its temporal trend, and to identify areas of risk for the occurrence of congenital syphilis in Sergipe, Northeastern Brazil. An ecological study of time series and spatial analysis techniques was performed, with municipalities as units of analysis. Data were obtained from the Notifiable Diseases Information System and included all cases of congenital syphilis reported from 2007 to 2015 in Sergipe. The local empirical Bayesian method used to minimize the rate variance. Spatial autocorrelation was used to analyze spatial patterns. 2,381 new cases of congenital syphilis were recorded in the studied period. A unique trend was found to increase the incidence, ranging from 2.7 (2007) to 11 (2015) per 1,000 live births. The average incidence in the period was 7.63 cases per 1,000 live births. Moran's global index was I = 0.64 (p<0.01), indicating the existence of spatial dependence; the Moran map identified 20 municipalities as priority areas of attention in Sergipe. There was a tendency to increase the incidence of congenital syphilis during the study period (2007-2010). As of 2010, the disease continued to grow, but with less growth than in previous years. As of 2011, there was stabilization with a remaining incidence of around 11 cases per 1,000 live births until 2015. The geographical distribution of the risk areas was heterogeneous, both due to the breadth of the territory and the concentration of cases in some regions.