Abstract

Background: Infection by Leptospira is relevant in canine medicine. However, prospective studies about leptospirosis in dogs are scarce worldwide. Methods: A prospective study among owned domestic dogs from southern Chile was performed by the Microscopic Agglutination Test: 1) to estimate the rate of serological conversion for anti-Leptospira antibodies in a 6 to 9 month follow-up period, 2) to determine the reactive serovars and, 3) to measure antibody titers in seropositive dogs. There were two samplings: in the first, 192 animals were sampled and 50 re-sampled dogs constituted the second. Results: The rate of serological conversion in the follow-up period was 12.0% (95% Confidence Interval=2.9-21.0%). In the first sampling, the most reactive serovars were Ballum and Canicola. In the second sampling, the most reactive serovar was Icterohaemorragiae. In both samplings, the antibody titers ranged between 1:100 and 1:800, with predominance titers of 1:100 and 1:200. Conclusions: The relatively high rate of serological conversion suggests that the exposure to Leptospira in dogs is present in southern Chile, with a possible endemic presentation of the seropositivity. Preventive measures such as vaccination and to reduce the exposition of pet dogs to reservoirs of the bacteria must be taken, as well to increase the awareness about Leptospira infection among public health institutions, veterinary practitioners and dog owners.