ANÁLISE ESPACIAL DA OCORRÊNCIA DE ACIDENTES OFÍDICOS NO BRASIL E SEUS DETERMINANTES AMBIENTAIS E SOCIOECONÔMICOS

Abstract

Recently the World Health Organization reclassified the snakebites as Neglected Tropical Disease. This problem mainly affects economically active age groups of rural populations in poor or in developing countries in tropical regions. Despite the low mortality rate associated with this type of accident in Brazil, one of the largest estimates of occurrence was attributed to the country. The epidemiological profile is widely known in several Brazilian regions, but little was inferred about factors associated with the occurrence of snakebites in the country. In order to analyze the spatial distribution of snakebites caused by snakes of the Elapidae and Viperidae families in the Brazilian municipalities between 2007 and 2015, we associate the number of snakebites with variables related to human factors (Area of the Municipality, Population, Agricultural Production, Municipal Human Development Index and Gross Domestic Product) and environmental factors (Species Richness, Remnant Area of Native Vegetation, Altitude and Climate). The records of notifications were obtained from the database of the Ministry of Health's Information and Notification System of Injuries. The average annual incidence rate for the time series analyzed was calculated. The association between the number of snakebites and factors analyzed was tested through Multiple Linear Regression Analysis by an OLS (Ordinary Least Square) model, evaluating the spatial autocorrelation in the model residues by the Moran Index. The variance partition was performed to evaluate the isolated effect of the different factors (environmental, human and spatial) on the variation of the accident data. Data were analyzed at national and regional scales. The average annual incidence for the period was 12.1/100,000 inhabitants. The North and Midwest regions presented the highest incidence, followed by the Northeast, South and Southeast regions, respectively. The OLS model indicated association more than 50% between snakebites data and variables tested, with the highest contribution of human factors followed the spatial effect and lower contribution of environmental factors in all scales. The model showed higher suitability especially for regions with the highest incidence rate, indicating differences in the composition of the most important variables in each region. However, it is possible to infer that in the analysis period, human factors contributed most heavily to the occurrence of snakebites in Brazil, followed by the spatial effect on the distribution of these snakebites and minor contribution of environmental factors. Clearly, the demographic density linked to type of occupation and climatic conditions may favor the increase of snakebites in the country, and different regional characteristics can clarify the disparity in the incidence rate among the Brazilian regions.