Submitted to: Journal of the American Veterinary Medical Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/1996
Publication Date: N/A
Interpretive Summary: Leptospirosis, caused by infection with various types of the bacterium Leptospira interrogans, is a cause of systemic illness, abortions, and death in many mammalian species. Leptospirosis is widely recognized as a cause of renal failure in dogs and commercial vaccines have been used to decrease the incidence of this disease. However, the incidence of leptospirosis in dogs has been increasing because of infections with serovars of the organism not contained in the vaccines. In this study, the clinical signs and diagnosis of 13 cases of leptospirosis in dogs are described. In addition, experimental infection studies were conducted to evaluate the ability of the leptospiral isolates to produce disease. The results of the this study indicate that leptospirosis caused by infection with L. interrogans serovar grippotyphosa is a common cause of renal failure in dogs and that this organism should be included in commercial canine leptospirosis vaccines. This information will be of use to practicing veterinarians, regulatory officials, and manufacturers of biologics.
Technical Abstract: From September 1992 to November 1994, 13 cases of canine leptospirosis were identified. Two dogs had serologic evidence of infection with Leptospira serovar canicola; the remaining 11 dogs had high levels of circulating antibody to serovar grippotyphosa, and this serovar was isolated from the urine and kidney of two dogs. Dogs infected with serovar grippotyphosa were from rural or suburban environments and had similar histories of progressive lethargy, anorexia, vomiting, and azotemia. Four dogs were experimentally infected with an isolate of serovar grippotyphosa that was obtained from the urine of one of the naturally infected dogs. While leptospires were reisolated from the kidney of one of these dogs at necropsy, evidence of disease was not observed. A stereotypical serologic response was observed in dogs naturally or experimentally infected with serovar grippotyphosa. The highest antibody titers developed against serovar grippotyphosa, with lower titers, due to antigenic cross-reactions, against serovars pomona and bratislava. The addition of serovar grippotyphosa to current canine leptospiral vaccines may be warranted due to the apparent increased incidence of disease in dogs attributed to infection with this serovar.