In this VETgirl blog, we review the transmission and clinical signs seen from canine leptospirosis. When it comes to leptospirosis, there are both saprophytic and pathogenic leptospires. Pathogenic leptospires are shed from renal tubules of both domestic and wild animals, and can remain viable in the soil and environment for weeks to months. That said, leptospires are inactivated by UV radiation and freezing. Infection can also occur through intact mucous membranes or abraded skin with direct or indirect exposure to urine. Rarely, leptospirosis can be transmitted via bite wound, ingestions of infected tissue (e.g., eating raw meat), or by venereal or placental transfer).
Canine leptospirosis classically presents with both acute kidney injury (AKI) and hepatic injury. Clinical signs include:
• Generalized malaise/listlessness
• Inappetance to anorexia
• Halitosis (e.g., uremia)
• Abdominal pain (e.g., secondary to AKI)
• Weight loss
*Note, the polyuria and polydipsia seen with canine leptospirosis may be seen irrespective if the patient is azotemic. This may be due to several causes: impaired renal concentrating ability secondary to a decreased glomerular filtration rate or decreased vasopressin responsiveness of the inner medullary collecting ducts (e.g., acquired nephrogenic diabetes insipidus).
Less common signs include hematuria, vasculitis (e.g., peripheral edema, pleural effusion, ascites, etc.), cardiac abnormalities, abortion (e.g., predominantly reported in cattle), and pulmonary signs. Pulmonary lesions may be secondary to leptospiral pulmonary hemorrhage syndrome (LPHS) or vasculitis. Clinical signs include tachypnea, dyspnea, acute respiratory distress syndrome (ARDS), and pulmonary hemorrhage. With leptospirosis, a secondary coagulopathy may also be seen due to hepatic failure (e.g., decreased production of activated Vitamin K factors II, VII, IX, and X), disseminated intravascular coagulation (DIC), or vascular damage (e.g., presumed to be secondary to the spirochetes). Clinical signs of coagulopathy include:
• Petechial hemorrhage
For more information, check out the free ACVIM Consensus Statement on Leptospirosis here.
References available upon request. Copyright, VETgirl, LLC 2014.