Leptospirosis (Canine)

Leptospirosis is an infectious disease of dogs and other animals (including humans) caused by multiple strains (servovars) of spiral shaped bacteria. Infection affects multiple organ systems including liver and kidney. Appropriate vaccination prevents disease in most cases although a disease free carrier state is possible and duration of vaccine immunity may be less than one year. Antibiotics are used to clear the organism.

Common name:Leptospirosis

Scientific name:Leptospirosis

Diagnosis

Signalment
Young dogs are more susceptible to leptospirosis than mature dogs. However, dogs of all ages can become infected.

Incidence/prevalence
Working dogs and herding dogs are at greater risk for contracting leptospirosis and outbreaks of the disease are known to occur after flooding when environmental contamination can be spread. Wildlife populations can serve a source of infection. Other dogs at increased risk include unvaccinated pets and those maintained in kennel situations with unsanitary conditions.

Geographic distribution
Leptospirosis occurs worldwide and is associated with warm weather in summer and fall. In rural areas dogs are exposed through standing water and moist soil (under appropriate conditions) that harbor the bacteria as well as materials contaminated with the organism. In cities, infected rodents themselves or their urine and other infected dogs are the primary means of exposure.

Clinical signs (primary, most to least frequent, scientific term, synonyms)
Shivering and muscle tenderness, fever, vomiting, diarrhea, polyuria (increased urination), polydypsia (increased drinking).

Clinical signs (secondary, most to least frequent, scientific term, synonyms)
Dehydration, jaundice (yellow tinged skin secondary to liver damage), coagulopathy (inability to stop bleeding), dyspnea (difficulty breathing).

Cause (scientific, common term)
Leptospira canicola, Leptospira icterohemorrhagica, Leptospira Pomona, Leptospira gripototyphosa, Leptospira autralis.

Organ system affected (most to least affected)
Kidney, liver, gastrointestinal, hemopoietic (blood and clotting factors), respiratory, brain.

Diagnostic tests
MAT (microagglutination test), ELISA (enzyme linked immunosorbent assay), PCR (polymerase chain reaction), CBC (complete blood count), serum chemistry profile.

Differential Diagnosis
Liver disease, kidney disease, canine distemper virus, Canine Parvovirus.

Overview

Leptospirosis is a bacterial infection of dogs and other animals. While the most common strains seen in dogs are Leptosirosis canicola and Leptospirosis icterohemorrhageia, other strains of Leptospirosis can cause disease in dogs as well as humans. Dogs living in rural areas are exposed to the infection through contact with contaminated stagnant water and soil with proper pH and moisture levels. Additionally, in rural areas, rodents, raccoons and other wildlife serve as a reservoir. Contact with materials contaminated with infected urine or feces can serve as a source of leptospirosis infection. Outbreaks tend to increase after flooding due to spread of environmental contamination. Urban dogs are exposed through contact with infected rodents and dogs or their urine. Shelters with unsanitary conditions also serve as a means of exposure. Infection with leptospirosis occurs by contact of infected material with the mouth or eyes, through open skin scratches or wounds and ingestion of contaminated material. In some cases, swelling and muscle tenderness are the first signs. However, clinical signs associated with kidney disease such as increased drinking and urinating, vomiting, diarrhea (with or without blood) and dehydration may occur. With some strains of leptospirosis, jaundice (yellow skin) associated with liver disease is the first obvious sign of this disease. Some dogs develop a carrier state with no evidence of clinical disease but can shed the organism for many months transmitting the disease to other dogs and humans.

Treatment

Home Care
Leptospirosis is contagious to humans and therefore affected animals should not be managed at home. Often affected dogs are very sick requiring intensive care in an isolation unit. When an animal is discharged from the hospital, latex gloves need to be worn by all persons handling the animal and dilute bleach applied to any area (inside or outdoors) where the dog has urinated or defecated.

Professional Care
Treatment with antibiotics typically is initiated when leptospirosis is suspected without waiting for laboratory confirmation. The MAT (microagglutination test) diagnoses leptospirosis by paired blood tests collected weeks apart. Other blood tests evaluate the status of the dogs' liver and kidneys and red and white blood cell counts. Intermittent follow-up tests are used to monitor response to treatment. Dogs sick from leptospirosis require supportive care for dehydration, control of vomiting and diarrhea, respiratory distress and antibiotics to treat the infection.

Action
Vaccines against leptospirosis are available from a veterinarian. Initially, two vaccine injections are required three weeks apart followed by annual booster. The vaccine does not prevent infections with all strains of leptospira. Depending on the strains in the environment, a vaccinated dog may become infected with a strain for which there is no vaccine available. Dogs at high risk of infection may require booster vaccination every six months.

Outcome
Full recovery from leptospirosis infection is possible. Depending on the circumstances and strain, long term management of liver, kidney and other organ damage may be required. Additionally, even when a dog appears clinically normal continued viral shedding for extended periods puts humans and other animals at risk. Death is possible.

References/Additional Readings

Ettinger, Stephen J., Feldman Edward C., Textbook of Veterinary Internal Medicine, 6th edition. Philadelphia: Elsevier Saunders, 2005: pp 616-619.

Greene, Craig E., Infectious Diseases of the Dog and Cat, 3rd edition. Philadelphia: Elsevier Saunders, 2006: pp 402-415.

Author

Ellen Hirshberg, DVM

Editor

Steven Hansen, DVM, MS, MBA

DABVT, DABT