Intra-urban dynamics of dengue epidemics in Belo Horizonte, Minas Gerais State, Brazil, 1996-2002

This study aimed to describe the temporal-spatial patterns of dengue epidemics in Belo Horizonte, Minas Gerais State, Brazil, from 1996 to 2002 and to analyze residential address as a proxy for exposure. Reported dengue cases were analyzed according to week of onset of symptoms and residential census tract. Local Moran's index was used to assess spatial autocorrelation of incidence coefficients, and recurrent census areas over different epidemic waves were also verified. Ripley's K-function was used to compare spatial distribution patterns between the two population groups, assuming that they were distributed differently around the city. A total of 99,559 dengue cases were analyzed, resulting in seven epidemic waves with different durations and intensities, with cases clustering in a small fraction of areas, thinning out both spatially and temporally. Distinct case distribution patterns were observed according to the two exposed groups, suggesting the need to improve the reporting of possible place of infection. The observed endemic pattern of the disease also requires specific strategies and poses a major challenge for health surveillance services.