The Urban Spread of Visceral Leishmaniasis: Clues from Spatial Analysis

BACKGROUND: The pattern of spread of visceral leishmaniasis in Brazilian cities is poorly understood. METHODS: We used geographic information systems and spatial statistics to evaluate the distribution of 1061 cases of visceral leishmaniasis in Teresina, Brazil, in 1993 through 1996. RESULTS: A locally weighted (LOESS) regression model, which was fit as a smoothed function of spatial coordinates, demonstrated large-scale variation, with high incidence rates in peripheral neighborhoods that bordered forest land and pastures. Moran's I indicated small-scale variation and clustering up to 300 m, roughly the flight range of the sand fly vector. CONCLUSIONS: Spatial analytical techniques can identify high-risk areas for targeting control interventions.