Analysis of the transmission of visceral leishmaniasis in the Brazilian northeast, during the period 2001-2015

Abstract

Visceral leishmaniasis (VL) is a major public health problem and a neglected tropical disease according the World Health Organization. The VL disease has a number of factors favorable to its expansion such as geographic extension, populational socio-demographic conditions as well as climate conditions. By considering this scenario the present study aims to identify possible climatic and sociodemographic factors that influence the transmission of VL. The climatic data used in this work were obtained from the Climate Prediction Center/ National Oceanic and Atmospheric Administration (CPC/NOAA) from January 2001 to December 2015. Sociodemographic data were obtained from the 2000 and 2010 brazilian censures, while populational projections were obtained from IBGE data center (IBGE: Portuguese acronym Instituto Brasileiro de Geografia e Estatística). Notifications of VL reported cases were provided by the Informatics Department of SUS - DATASUS (SUS: Portuguese acronym for Sistema Único de Saúde. For the three-year averages (2001-2003 and 2013-2015) the Moran index was used in order to perform a spatial analysis of the data. For the three-year average from 2001 to 2003 it was observed I = 0, 00 with p value = 0,010. While the three-year average from 2013 to 2015 resulted in I = 0, 00 with p value =,01. Furthermore, the Mantel-Haenszel statistical test was used in order to investigate the relationship between the type of LV transmission and several variables such as population estimate, degree of urbanization, the Municipal Human Development Index (IDHM: Portuguese acronym Indice de Desenvolvimento Humano), inadequate sanitation, minimum, mean and maximum temperature, cumulative rainfall, relative air humidity and altitude. For both investigated periods the test resulted in a significant association between variables: Resident estimated population, degree of urbanization, IDHM and inadequate sanitation versus the type of LV transmission. Also, the Mantel-Haenszel test has shown significant association between the type of LV transmission and climate variables temperature (mean, minimum and maximum), cumulative rainfall and relative air humidity, especially in the period 2013-2015.