Leptospirosis in Dogs

Written by Small Door's medical experts

Leptospirosis is a dangerous bacterial disease that affects dogs and other animals, including people. It can cause kidney and liver failure, and in severe cases it can be fatal. Luckily, there are things you can do to prevent leptospirosis – most importantly, vaccinating your dog. Understanding how this disease is spread and the preventative measures you can use can help keep your family safe.

In This Article

Signs and Symptoms of Leptospirosis in Dogs

Symptoms of leptospirosis can vary and initially are non-specific. These are some signs of leptospirosis that dog owners should be aware of, especially in dogs that spend time outdoors.

  • Fever

  • Shivering

  • Decreased appetite

  • Increased thirst

  • Jaundice (yellowing of the skin, whites of the eyes and gums)

  • Lameness/Joint or muscle pain/reluctance to move

  • Vomiting

  • Dehydration

  • Lethargy

The first symptoms of a leptospirosis infection are usually lethargy, fever, shivering, and a decreased appetite. As the infection worsens, vomiting and dehydration are likely to occur. Additionally, in some cases, leptospirosis can cause: lung damage leading to a cough and signs of respiratory difficulty, inflammation of the eyes, bleeding disorders, and swollen limbs from fluid accumulation as the kidneys and/or liver become progressively damaged.

How Did My Dog Get Leptospirosis?

Leptospirosis in dogs is caused by a family of bacteria called Leptospira. There are approximately 21 known species of leptospires. Mice, rats, deer, opossums, and raccoons all serve as reservoirs for leptospirosis. As these bacteria are shed in the urine of these carrier animals, water and/or soil becomes contaminated and can remain so for a long time.

Some or all of these species can be found in every place of human habitation, which means most dogs are at risk of exposure to leptospirosis at some point during their lives. Veterinarians have noted that disease outbreaks occur frequently after periods of flooding or heavy rain, as the bacteria can survive in surface waters for extended periods of time.

Contraction of the disease can be direct or indirect. The most common pathway is through contact with contaminated urine and/or soil water, as the bacteria can penetrate the mucous membranes of the nose and gums, and through small wounds or scratches, especially on the footpads. Transmission can also occur through the placenta during pregnancy.

Diagnosing Leptospirosis in Dogs

After obtaining the dog’s history from the owner, assessing the symptoms, and performing a physical examination, veterinarians who suspect leptospirosis typically turn to laboratory tests to confirm the diagnosis.

Complete blood cell counts help to evaluate platelet numbers as well as the number of red and white blood cells. Further tests, like a blood chemistry profile, evaluate kidney and liver function, along with electrolytes. Urine tests are also used to gauge kidney and liver function; these tests measure the severity of the disease, which can help your veterinarian determine if your dog requires hospitalization.

Other tests, such as the DNA-PCR, test for bacteria in the urine. This is a rapid test to obtain a definitive diagnosis, and it must be performed prior to antibiotic administration, as the bacteria are easily killed. In addition, in early or chronic cases where only very low levels of bacteria may be present in the urine, false negative results from this test may occur.

In contrast, the microscopic agglutination test (MAT), looks for antibodies in the blood. However, antibodies may not show up early in the illness, so the test may need to be repeated 2 to 3 weeks after the symptoms have first been noted to see if an increase has occurred.

Treating Your Dog For Leptospirosis

Leptospirosis is a serious condition. Up to 25% of severe cases of leptospirosis are fatal, and severely affected dogs will need hospitalization. Once hospitalized, they will receive intensive care, including fluids and urinary catheter placement to measure urine production. All cases of suspected lepto are treated with antibiotics as soon as possible.

Antibiotics are effective for treating leptospirosis in 2 phases. One type of antibiotic is used for the first, acute phase (2 weeks) to rapidly kill the infection. After this period, another antibiotic is administered for another 2 to 4 weeks to eliminate the lingering, low grade infection that can remain in your pet’s kidneys. This also minimizes shedding of the leptospira bacteria in their urine, helping to minimize the spread of the disease to other animals.

Is There a Cure for Leptospirosis?

Leptospirosis can be cured with antibiotics, if recognized and treated in the very early stages of illness. However, even with treatment, over 80% of dogs develop serious, short term kidney problems and some cases of leptospirosis can be fatal.

Is Leptospirosis Contagious for Humans or Other Pets?

Yes, leptospirosis is contagious for humans and other pets. While cats rarely contract lepto, it can easily infect other dogs as well as people. If your pet has been diagnosed with lepto, it is important to avoid contact with your pet’s urine, practice good hand hygiene, and once they are home, ensure they urinate away from areas that other dogs may come across, as well as away from water to reduce contamination for other pets. If you develop any flu-like symptoms and have had exposure to lepto, contact your doctor right away.

What Is the Cost for Treating Leptospirosis?

The cost of treatment for leptospirosis will vary depending on the severity of the infection. If hospitalization and intensive care are required, the cost can range from several hundred to several thousand dollars, depending on the length of the hospital stay. Milder cases can expect to run to at least several hundred dollars, as the cost of the visit, exams, blood work, medication, and follow-up tests quickly add up.

Recovery and Management of Leptospirosis in Dogs

Because leptospirosis is a zoonotic disease (i.e. a disease that can pass from animals to humans), your veterinarian will place your dog in isolation. Milder cases that do not require hospitalization should also be treated with care; your dog should be isolated from other pets and humans in the home. Gloves should be worn when handling bedding or any surface that may have come in contact with infected urine, and you should wash your hands after handling your dog.

Your veterinarian may recommend additional safety measures, like wearing a facemask and goggles when hosing down kennels. Diluted bleach effectively eradicates the bacteria from most surfaces.

Encourage your dog to urinate in the same location for the duration of the disease, preferably on a surface that is easily decontaminated, like concrete or asphalt.

Once your dog begins to recover, they will need additional laboratory tests to measure their organ function. Most leptospirosis cases that are caught in the early stages recover and respond well to treatment.

However, because symptoms are non-specific, diagnosis is often delayed, which can have severe consequences. Even for those that recover, there can be long-term kidney or liver disease, which will require further management.

Preventing Leptospirosis in Dogs

Getting your dog vaccinated against leptospirosis and keeping them up to date on vaccine boosters is the best way you can protect them against the disease.

In addition to the vaccine, you should minimize your dog’s encounters with wild animals and carrion, and discourage drinking from water sources found outdoors, like streams, lakes, ponds, and puddles. When taking long walks, ensure you bring a collapsible water bowl and fresh water for your dog, and offer it to them regularly so they are not tempted to drink from potentially unsanitary sources of water.

Is There a Vaccine for Leptospirosis?

Yes, vaccines are available for four of the most common leptospira bacteria, and your veterinarian will know which are most common in your area. Most boarding facilities require a leptospirosis vaccine, as the disease spreads quickly in crowded conditions.

The leptospirosis vaccine is not considered a ‘core vaccine’ by all veterinarians, and so some may only recommend it if your pet is likely to spend time in high-risk areas for lepto.

At Small Door, we do consider leptospirosis a core vaccine that is essential for your dog’s health. This is because leptospirosis is found across all five boroughs of New York and is even more prominent outside of the city, so we strongly recommend that all of our dog members receive the vaccine.

Check out our article on vaccine schedules for more information about when your dog should receive their initial leptospirosis vaccine and boosters.

Summary of Leptospirosis in Dogs

Leptospirosis is a serious and potentially fatal zoonotic bacterial infection, but thankfully it is preventable. Vaccination is the number one way you can protect your dog, so we strongly urge all pet owners, particularly those based in New York, to administer this as part of your pet’s yearly vaccinations. Vaccines are well tested, very safe, relatively painless and inexpensive, and could save your pet from a serious, life-threatening illness. If you suspect that your dog has been exposed to leptospirosis or is exhibiting symptoms of the disease, contact your veterinarian immediately.

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