[Leptospira interrogans in a canine population of Greater Buenos Aires: variables associated with seropositivity]

We determined the seroprevalence of leptospirosis in a suburban canine population for the purpose of analyzing the association between different individual and environmental variables and seropositivity for leptospirosis. The study, which was cross-sectional, was performed in July 1992 in a neighborhood of Greater Buenos Aires with approximately 9,500 inhabitants and a canine population of around 2,000 animals. We studied a random sample of 223 dogs and obtained a blood sample from each. Each animal's epidemiologic history was obtained by interviewing the housewife. Serologic measurements were performed by the microagglutination technique with the use of 10 different serotypes of Leptospira interrogans. Of the 223 dogs that were tested, 57% showed seropositivity; 82% of the positive sera coagglutinated with two or more serotypes. The most frequently detected serotypes were canicola and pyrogenes. Seroprevalence in females was less common than in males (P < 0.05) and in puppies less than 1 year old it was less common than in older animals (P < 0.01). Street behavior in the dog and the presence of stagnant water in front of the owner's dwelling were the most important of the risk factors examined. The associations between seropositivity on the one hand and contact with trash deposits, hunting behavior and the presence of rodents inside the dwelling on the other were not statistically significant. Different control measures are discussed.