Assessing epidemiology of leprosy and socio-economic distribution of cases

Leprosy still represents a serious health problem in a number of countries, including Brazil. Although leprosy has been associated with poverty for a long time, it is still difficult to accurately define this relationship. Here, we evaluated in an endemic municipality the progress from 1995 to 2015 of epidemiological indicators to establish if there were any strong associations between social indicators and the occurrence of leprosy. An ecological study was conducted using the SINAN database (Brazilian leprosy-national notifiable diseases information system) in combination with georeferencing of leprosy cases. The georeferencing used the ArcGis programme and occurrence of cases was evaluated in relation to the Health Vulnerability Index (HVI), an indicator that categorises socio-economic and sanitation factors. The data identified a marked decrease in the overall prevalence of leprosy, a reduction in the new case-detection rate and a reduction in the number of cases with grade 2 disabilities (albeit with transient peaks in 2007 and 2015). Logistic regression analysis showed association of detection rates with elevated HVI. Thus, while the epidemiological indicators point to the elimination of leprosy, there is evidence of hidden cases and an association between higher rates of leprosy detection and greater social vulnerability remain.