Leptospirosis in a mixed breed female dog (Canis familiaris)

The present study aimed to report a clinical case of leptospirosis diagnosed in a mixed breed dog where treatment was chosen without hospitalization. Leptospirosis is an infectious and contagious zoonotic disease caused by the spirochete of the genus Leptospira spp. All pathogenic lineages belong to a single species, Leptospira interrogans. This microorganism can affect both humans and animals, be they domestic, wild or production. Dogs and cats are susceptible, but felines have greater resistance to leptospirosis. Synanthropic rodents in large urban centers or rural areas constitute a major problem, as they end up transmitting it to domestic and stray animals. Animals become infected and end up eliminating spirochetes into the environment through contaminated urine, since leptospirosis has a predilection for the renal tubules. Transmission can be direct through contaminated urine, venereal secretions, placental transfer, bite wounds or ingestion of contaminated tissues. Leptospira can enter the body through intact oral, nasal or ocular mucous membranes, or through skin that is damaged or macerated by moisture. Indirect transmission occurs through contact with contaminated water, soil and food sources. In Brazil, where many locations lack a garbage collection system and sewage disposal is precarious, the tropical climate favors rain during summer, all increasing the role of rodents as vectors of this zoonosis due to flooding. The canine mentioned in this study did not have their vaccination protocol up to date, lived in a place with the presence of rodents, and was diagnosed positive for L. interrogans serovars Bratislava, Pomona and Copenhageni by the microscopic agglutination test (MAT), considered the gold standard. The changes in the blood count were limited to normocytic normochromic anemia and hyperproteinemia. No noteworthy changes were observed in the white blood cell count and, in the biochemical tests, liver and kidney changes consistent with the pathology were evident. The therapeutic protocol chosen was antibiotic therapy and supportive therapy, both carried out at the guardian's home, and the prognosis was favorable. Preventive vaccination measures according to the challenge faced in the environment, rodent control and also public policies regarding basic sanitation are important in preventing in zoonosis.