Overview
Leptospirosis in dogs, sometimes referred to by the short-hand, lepto in dogs, is an infectious disease caused by bacteria in the genus Leptospira. Dogs are the primary host of Leptospira serovars, and many other mammal species can also be infected. Clinical signs range from mild, subclinical infection to multi-organ failure and death. Diagnosis includes serologic testing and identification of leptospires in tissues, blood or urine. Doxycycline is the primary drug used for treatment in dogs, along with appropriate supportive care. Polyvalent vaccines are available for prevention. Specific serovars in a geographic area vary, so vaccines with the appropriate types should be used.
Clinical findings
Acute kidney injury has been the most common presentation for canine leptospirosis in recent years. Dogs affected by leptospirosis may show these clinical signs
- Acute liver disease may accompany acute renal failure in dogs with leptospirosis, or it may occur alone. Affected dogs may be icteric, and serum biochemistry analysis reveals increased bilirubin and alkaline phosphatase. ALT is typically less markedly increased than alkaline phosphatase.
- Muscle pain, stiffness, weakness, trembling, or reluctance to move can be seen in dogs with leptospirosis. These may be the result of vasculitis, myositis, or nephritis. Myalgia is commonly reported in human leptospirosis and is associated with the septicemic phase of the disease.
- Urinalysis may reveal: hyposthenuria, isosthenuria, or hypersthenuria, depending on the degree of renal involvement., proteinuria, glucosuria, cylindruria, hematuria, pyuria. Leptospirosis could also potentially be associated with renal tubular acidosis.
- Changes noted on ultrasonography include:
- renomegaly
- pyelectasia
- increased cortical echogenicity
- perinephric effusion
- a hyperechoic medullary band
Diagnosis and differentials
Ideally, a combination of serology and organism detection should be used for diagnosis of canine leptospirosis. Serology is the most frequently used diagnostic test for dogs. Acute and convalescent titers may be necessary to confirm a diagnosis; hence, the use of the MAT is preferred over the ELISA. PCR-based tests are widely available, and collection of both blood and urine samples before administration of antibiotics should be considered for maximal sensitivity. The results of all diagnostic tests should be interpreted in light of the animal’s vaccination history, clinical signs, and clinicopathologic findings.
Treatment and control
Drugs of Choice is doxycycline, with appropriate supportive care as needed.
- Renal failure and liver disease are treated with fluid therapy and other supportive measures to maintain normal fluid, electrolyte, and acid-base balance.
- Supportive measures may include:
- antiemetics
- GI protectants
- phosphate binders
- hepatic support medications
- Renal replacement therapy with intermittent hemodialysis or continuous renal replacement therapy should be considered for dogs that are anuric or oliguric despite appropriate supportive therapy. Antibiotic therapy is indicated whenever leptospirosis is suspected and should be instituted before confirmatory test results are available. There are no experimental studies in dogs to guide selection of antibiotic protocols for this species.
- Current recommendations are to treat with doxycycline (5 mg/kg/day, IV or PO) for 2 wk. For dogs that cannot tolerate doxycycline, initial therapy with a penicillin is appropriate, but this should be followed by a 2-wk course of doxycycline to eliminate the renal carrier phase of infection. Dogs recently exposed to leptospirosis may be treated prophylactically with oral doxycycline for 14 days.