Relative Risk of Visceral Leishmaniasis in Brazil: A Spatial Analysis in Urban Area

Abstract

BackgroundVisceral leishmaniasis (VL) is a vector-borne disease whose factors involved in transmission are poorly understood, especially in more urban and densely populated counties. In Brazil, the VL urbanization is a challenge for the control program. The goals were to identify the greater risk areas for human VL and the risk factors involved in transmission.MethodologyThis is an ecological study on the relative risk of human VL. Spatial units of analysis were the coverage areas of the Basic Health Units (146 small-areas) of Belo Horizonte, Minas Gerais State, Brazil. Human VL cases, from 2007 to 2009 (n = 412), were obtained in the Brazilian Reportable Disease Information System. Bayesian approach was used to model the relative risk of VL including potential risk factors involved in transmission (canine infection, socioeconomic and environmental features) and to identify the small-areas of greater risk to human VL.Principal FindingsThe relative risk of VL was shown to be correlated with income, education, and the number of infected dogs per inhabitants. The estimates of relative risk of VL were higher than 1.0 in 54% of the areas (79/146). The spatial modeling highlighted 14 areas with the highest relative risk of VL and 12 of them are concentrated in the northern region of the city.ConclusionsThe spatial analysis used in this study is useful for the identification of small-areas according to risk of human VL and presents operational applicability in control and surveillance program in an urban environment with an unequal spatial distribution of the disease. Thus the frequent monitoring of relative risk of human VL in small-areas is important to direct and prioritize the actions of the control program in urban environment, especially in big cities.

An Integrated Approach Using Spatial Analysis to Study the Risk Factors for Leishmaniasis in Area of Recent Transmission

“…A spatial correlation demonstrating the simultaneous occurrence of human, canine, and proven vectors especially in the south, northeast, and northwest regions was observed. As the human cases are still very low when compared to endemic cities of the Minas Gerais state [8, 10, 13], control measures at this point may help to avoid human transmission and decrease canine infection.…”

Canine visceral leishmaniasis in an urban setting of Southeastern Brazil: an ecological study involving spatial analysis

“…Geographic information systems and spatial analysis of infectious diseases have become common tools and are used widely by Brazilian researchers working in the field of leishmaniasis [7,18,19,22,[24][25][26][27]. Spatial analysis allows the visualization of regions with the highest prevalence of the disease and assists in the identification of associated risk factors and in the design of appropriate management strategies.…”

“…The technique has been widely employed in the study of leishmaniasis and has permitted detailed analyses of the spatial dependency between canine and human VL, the distribution of the vector, and the characterization of areas with high incidence and high risk of morbidity [7,[18][19][20][21][22][23][24][25][26][27].…”

Geoprocessamento Aplicado À Epidemiologia Da Leishmaniose Visceral

“…As análises foram realizadas no Laboratório de Epidemiologia Veterinária da Universidade Federal de Mato Grosso do Sul (EpiVet-UFMS). Araújo et al (2013) sugerem que a variação encontrada entre as incidências avaliadas por bairro da capital (0,0 a 6,9/10.000 hab.) está correlacionada ao nível educacional e socioeconômico da população.…”