Prevalence of anti-Leptospira interrogans agglutinins in dogs captured by the Zoonosis Control Center, in nine administrative districts of Belo Horizonte city, throughout the year, was evaluated. The areas with positive prevalence were correlated to the areas of environmental sanitation, using sources of georeference. Blood samples from 3,417 dogs captured, were submitted to microscopic agglutination test from September 2001 to September 2002, showed 13.1% of seropositivity. The most reactive serovars were Canicola, Ballum, Pyrogenes and Icterohaemorrhagiae. High prevalences were observed at Center-Southern - 22.5%, Eastern - 19.1% and Northeastern - 13.2% districts. Pampulha district got 8.2% of prevalence, the lowest percentage of positive reactions. High number of dog infection was observed during December, 2001 and January, 2002, characterized as rainy period and high environmental temperature. Villages, slums and suburbs with environmental sanitation deficiency are areas of high risk.
dog; Leptospira interrogans; prevalence; spatial distribution
