Análise da distribuição temporal e espacial da leishmaniose tegumentar americana em Minas Gerais e no município de Januária-MG, 2007-2015

Abstract

Leishmaniasis is considered a complex of neglected diseases by the World Health Organization (WHO), which especially affects poor populations. The disease is present in 98 countries throughout the world and approximately 200 to 400 thousand cases of visceral leishmaniasis and 0.7 to 1.2 million cases of cutaneous leishmaniasis are reported each year. American Tegumentary Leishmaniasis (ATL) is an important public health problem in Brazil, as well as in other regions of the world. Considering the American continent, Brazil is the country with the highest number of registered cases (78,8%). Within Brazil, the State of Minas Gerais has been notifying cases of ATL since the second half of the past century and it is the state with the highest number of registered cases in the south-eastern region. The objectives of the present study were to identify municipalities of priority for vigilance and detect temporal changes in the distribution of ATL in Minas Gerais, Brazil. Also, newly registered cases were evaluated on a spatial and spatial-temporal basis during a time period between 2007 and 2015. Two different studies were conducted. First, an ecological study identified municipalities of priority for vigilance against ATL in Minas Gerais, which included all notified cases between 2007 and 2015, In this first step, secondary data from the Brazilian Ministry of Health for the notification of visceral and tegumentary leishmanisis (SINAN) were used. Analyses were subdivided in three-year periods and incidence rates were calculated for each municipality, using a Bayesian Empirical smoothing approach. We also calculated Moran’s Global Index in order to check for spatial autocorrelation and generated the Local Indicators of Spatial Association (LISA). The mean incidence rate for the entire state and period was 6.1 per 100,000 inhabitants. For the above mentioned time period we observed a subsequent increase in the number of mesoregions with priority municipalities with the state. In this respect, 8 and 4 mesoregions contained high priority municipalities in any or in each of the investigated trienniums, respectively. In conclusion, a total of 124 municipalities were classified as high priority areas in at least one of the three-years periods, of which 36 municipalities were classified as high priority throughout the entire investigation. Second, we performed an observational, cross-sectional and retrospective study on notified ATL cases of individuals residing in the municipality of Januária, Northern region of Minas Gerais. This study was based on data collected from medical reports of infected and treated individuals during the time period from 2007 to 2015. Monthly incidence rates for ATL were correlated with the mean monthly humidity, rainfall, and with temperature. Spatial analyses included Kernel’s density, standard deviational ellipse, and a spatial and spatial-temporal scan. A significant positive correlation between ATL cases and humidity and rainfall was found. The application of spatial scan revealed two clusters of high and two of low risk within the municipality. Clusters of high risk were located in rural areas, whereas one of the low risk areas were located in a rural and one in an urban setting. When a spatial-temporal scan was applied, two clusters of high risk were identified in the rural area in 2007 to 2009 and one cluster of only low risk in the urban area from 2013 to 2015. For the Municipality of Januária, the districts of Brejo do Amparo and Riacho da Cruz together with Levinópolis were the areas with the highest relative risk (RR) for ATL infection, being 16.8 and 4.3 times higher than in no risk areas, respectively. By the use of data from the Geographic Information System (GIS), we were able to identify priority areas for vigilance and it will be possible to direct resources for control of ATL on the state and the municipality level.