Leptospirosis is an emerging zoonotic infectious disease of humans and dogs. It is seen globally and has been reported in over 150 mammalian species. Pathogenic serovars have adapted to different wild and domestic reservoir hosts. Recognition of serovars is important in epidemiologic studies. Clinical syndromes in dogs with leptospirosis vary depending on the infecting strain, geographic location, and host immune response. Dogs are at risk, including small-breed dogs in both rural and suburban environments. Dogs may have no signs of clinical disease or may develop severe illness or die. Leptospirosis should be included on the differential list for dogs with signs of renal or hepatic failure, uveitis, pulmonary hemorrhage, acute febrile disease, or abortion. Infected dogs shed viable organisms and may continue to shed organisms for months if appropriate antibiotic therapy is not initiated. Caution is recommended with dogs in the clinic, and their movements around the hospital should be minimized. Areas of contact with infected dogs should undergo disinfection. Gloves, protective eyewear, and a disposable gown should be worn when working with infected patients. Runs where infected dogs have been staying should not be pressure washed, as this may contribute to urine aerosolization. Vaccines that include serovars (Leptospira) icterohaemorrhagiae, canicola, grippotyphosa, and pomona are available in North America. Vaccines appear to protect for at least 12 months. Although there is some concern about development of anaphylactoid reactions in dogs, especially small dogs, there is anecdotal evidence that prevalence of these reactions is decreasing.

Commentary: This consensus statement, available at acvim.org at no charge, is an excellent review of the literature on leptospirosis. It should be studied by those in clinical practice. Annual vaccination can prevent leptospirosis caused by vaccine serovars and should be encouraged for dogs at risk.—Patricia Thomblison, DVM, MS

2010 ACVIM small animal consensus statement on leptospirosis: Diagnosis, epidemiology, treatment, and prevention. Sykes JE, Hartmann K, Lunn KF, et al. J VET INTERN MED 25:1-13, 2011.