Serologic, Pathologic, and Immunologic Features of Experimentally Induced Leptospiral Nephritis in Dogs

Abstract

SUMMARY A study was conducted to determine if a relationship existed beween pathologic changes in the kidneys and immunologic responses of dogs given single or multiple injections of viable and nonviable Leptospira canicola . The course of the disease was evaluated by clinical observations, fluorescent antibody ( fa ) tests, and blood, urine, gross, and histopathologic examinations. Clinical signs, increased white blood cell ( wbc ) counts, and increased erythrocyte sedimentation rates ( esr ) occurred in the 10 dogs inoculated with viable leptospires (5 given a single injection and 5 given 5 injections approximately 3 weeks apart) and were related to the hyperthermic and leptospiremic stages of infection. On experimental day 4, leptospiremia was observed in all of the 10 dogs given viable leptospires, and on day 7 leptospiremia was observed in 7 of the 10 dogs. On days 25 and 28, leptospiremia recurred in 2 of 5 dogs given a single inoculation of viable leptospires 25 and 28 days previously, although antibodies (titers of 10 4 and 10 5 ) were detected in their serums on both of these dates. Antibodies detectable by the microscopic agglutination ( ma ) test were found in the serums of dogs inoculated with viable leptospires 3 days earlier (day 11 compared to day 14), and their serum titers were consistently higher than those of dogs inoculated with nonviable leptospires. Since there was little overall difference in the ma titers of the serums of dogs given single or multiple inoculations of viable leptospires, perhaps reproduction of the leptospires continued in the tissues of dogs given the single inoculation of viable organisms. Leptospiruria was detected with almost equal frequency in dogs given single or multiple inoculations of viable leptospires (77.8 and 72.2%).