Introduction: The incidence of canine leptospirosis in Brazil needs to be assessed.
Methods: The same dogs in southern Brazil were sampled over two years to determine the prevalence, incidence and association of canine leptospirosis with various risk factors.
Results: In 2009, the prevalence was 33 (14.4%) of 228 dogs, with a predominance of serovar Canicola (33.4%). In 2010, 90 dogs were re-evaluated (the remaining dogs were lost to deaths, address changes and donations), and the prevalence was found to be 35 (38.9%) of 90, with the predominant serovar being Icterohaemorrhagiae (51.4%). Moreover, the incidence was 26 of 90 (28.9%), and the disease was statistically associated with age (2009) and street access (2010).
Conclusions: Our findings revealed instability in the dog population and age to be relevant risk factors for canine leptospirosis.