Leptospirosis is a dangerous, life-threatening disease, yet a vaccination for it is not part of the core vaccines every dog routinely receives. Whether your dog should be vaccinated depends on their lifestyle and risk factors. For example, dogs who go camping and hiking should clearly be protected; however, dogs who rarely step foot outside probably have little chance of becoming infected. To help you decide where your pet falls, and whether they should receive the vaccine, our Palmer Vet Clinic team explains leptospirosis basics.

What is leptospirosis?

Leptospirosis is an infection caused by the spirochete bacteria Leptospira interrogans, which is shed in the urine of infected animals. Wild animals, including rodents, raccoons, skunks, opossums, and deer, serve as infection reservoirs for other wild animals and dogs. 

How do dogs contract leptospirosis?

When infected animals urinate in the environment, soil and water become contaminated with the bacteria, which can live for weeks to months. Bacteria can penetrate a dog’s skin or mucous membranes, and most commonly enter the body through the eyes, nose, or mouth. Dogs often become infected by swimming in or drinking from a contaminated water source, such as a lake, pond, stream, or puddle. 

How does leptospirosis affect dogs?

Leptospirosis infection can cause a variety of problems, including:

  • Acute kidney failure — Kidney failure is the most common sign of leptospirosis, and is characterized by abdominal pain, vomiting, and urine volume changes. Dogs with mild kidney failure typically produce larger volumes of dilute urine, while pets with severe kidney failure may produce less urine, or none at all. Dogs who survive leptospirosis-related acute kidney failure may return to normal function, or may progress to chronic renal failure.
  • Acute liver failure — Liver failure often develops concurrently with kidney failure. The liver plays a part in many important functions, such as blood clotting, protein production, and waste removal. Dogs that develop liver failure typically become “jaundiced,” with characteristic yellowish skin and mucous membranes.
  • Bleeding disorders — In addition to clotting disorders brought on by liver failure, dogs with leptospirosis can develop vasculitis, which damages the blood cell lining. Blood can leak out of affected vessels, causing bruising, petechiae (i.e., pinpoint bruising), nose bleeds, pulmonary hemorrhage, or blood loss in the urine or feces.
  • Eye problems — Infected dogs occasionally develop uveitis (i.e., internal eye inflammation), although this is uncommon. 

In addition to affecting dogs, leptospirosis is a zoonotic disease, meaning it can be passed to people. Human infections most commonly occur after people swim in contaminated water, but can also occur from handling an infected dog’s urine. 

What are leptospirosis signs in dogs?

Since leptospirosis affects various body systems, the signs can vary. In addition to the symptoms mentioned above, pets may experience generalized illness signs, such as:

  • Lethargy
  • Fever
  • Decreased appetite
  • Vomiting
  • Diarrhea
  • Weight loss
  • Ocular and nasal discharge
  • Lymph node enlargement
  • Swelling

If your dog develops any such signs of illness, have them evaluated by our Palmer Vet Clinic team immediately. Although some illnesses are not serious, infections such as leptospirosis can quickly advance and become life-threatening. 

How is leptospirosis diagnosed in dogs?

Leptospirosis is diagnosed with a blood test that detects Leptospira antibodies, which indicate the dog’s immune system has recently been exposed to the pathogen. An active infection can be confirmed by detecting Leptospira bacteria in a dog’s urine. To determine the disease’s extent and severity, additional tests may be performed, including: 

  • Complete blood count
  • Blood chemistry
  • Urinalysis
  • Abdominal ultrasonography

How is leptospirosis treated in dogs?

Since leptospirosis is a bacterial infection, antibiotic therapy is the most important component of treatment. Pets may require additional supportive care, either at home or in our hospital, while they recover, which may include:

  • Intravenous (IV) fluid therapy, to support the kidneys and maintain normal fluid, electrolyte, and acid-base balance
  • Medications to support the liver
  • Anti-vomiting medications
  • Gastric protectants

Treatment is continued until the infection has been eliminated, and the dog’s various organ systems return to normal function, although kidney and liver failure may cause permanent damage. Without treatment, kidney and liver failure can progress to chronic organ failure, or death. 

Which dogs should receive the leptospirosis vaccine?

Our Palmer Vet Clinic team carefully considers each pet’s lifestyle and risk factors before making vaccine recommendations. Dogs with moderate to high exposure risk should receive the leptospirosis vaccine, including those who:

  • Spend a lot of time outdoors
  • Go camping or hiking with their owner
  • Swim in natural water sources, such as ponds, lakes, or streams
  • Drink from natural water sources or puddles
  • Share space with wild animals, including their backyard if wild animals have access

The leptospirosis vaccine is highly effective, and is recommended for any dog who may be exposed to infection. Protection lasts approximately one year, so the vaccine should be boostered annually during your dog’s yearly wellness visit. 

Leptospirosis is a serious disease, but your dog can be safely protected. Contact our Palmer Vet Clinic team with any questions about leptospirosis, or to schedule your dog’s vaccination.