Relative risk of visceral leishmaniasis in Brazil: a spatial analysis in urban area.
BACKGROUND
Visceral 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.


METHODS
This 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.


RESULTS
The 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.


CONCLUSIONS
The 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.
Laboratório de Epidemiologia de Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil ; Secretaria Municipal de Saúde, Prefeitura de Belo Horizonte, Belo Horizonte, Minas Gerais, Brazil.
Valdelaine Etelvina Miranda
VE
de Araújo
Letícia Cavalari
LC
Pinheiro
Maria Cristina de Mattos
MC
Almeida
Fernanda Carvalho
FC
de Menezes
Maria Helena Franco
MH
Morais
Ilka Afonso
IA
Reis
Renato Martins
RM
Assunção
Mariângela
M
Carneiro
D001938:Brazil / Q000453:epidemiology; D006801:Humans; D007898:Leishmaniasis, Visceral / Q000453:epidemiology* / Q000635:transmission; D012307:Risk Factors; D014505:Urban Population