The socio-demographic, environmental and reservoir factors associated with leptospirosis in an urban area of north-eastern Brazil

In an ecological study based on the 18 microregions that form the city of Recife, the capital of the Brazilian state of Pernambuco, associations between socio-demographic, environmental and reservoir factors and the incidence of leptospirosis in the city were investigated. Incidence over a 5-year period (2001-2005) and 14 variables were analysed, using central trend and dispersion measurements, Pearson's correlation and multiple linear regression. Variables relating to education, income, housing type, sewage system, rubbish collection and hydrographic factors were found to be significantly correlated with leptospirosis incidence (P<0.05 for each). Just two variables - the proportion of heads of households with incomes less than or equal to the legal minimum (U.S.$83.55/month), and the proportion of households from which rubbish was dumped in skips, lakes, rivers or the sea or on vacant land explained 60% (P=0.017) of the differences in disease risk observed between the various areas of the city.