Leptospirosis in Dogs: Signs, Causes, Treatment

Leptospirosis in dogs is a bacterial infection every pet parent should know about. Caused by Leptospira bacteria, leptospirosis can affect important organs such as the kidneys and liver and may become serious if left untreated. Since dogs can be exposed during everyday activities, especially when they come into contact with water, soil, or environments contaminated by infected animals, prevention is especially important.

Thankfully, leptospirosis can be avoided through vaccination and other precautions, and many infected dogs can recover with prompt veterinary treatment. To help protect your pet’s well-being, let’s look at the signs, treatment, and prevention of leptospirosis in puppies and adult dogs.

KEY TAKEAWAYS

• Leptospirosis is a bacterial infection spread through infected animals' urine.
• Signs include fever, lethargy, vomiting, jaundice, and increased thirst.
• It is diagnosed with blood and urine tests; treatment is antibiotics plus supportive care.
• Vaccination is the most effective prevention, discuss it with your vet.
• Leptospirosis is zoonotic, meaning it can spread from dogs to humans.

What Are The Signs and Symptoms of Leptospirosis in Dogs?

The early signs of leptospirosis in dogs can look similar to many other illnesses. Common symptoms include fever, shivering, muscle tenderness, lethargy, loss of appetite, increased thirst, changes in urination, vomiting , and diarrhea .

As the infection progresses, kidney or liver damage may occur. Signs can include dehydration, weakness, reduced urination, and jaundice, which may cause yellowing of the skin, gums, or whites of the eyes. Eye redness can also occur in some dogs. Because any sign of leptospirosis in dogs can be difficult to distinguish from other conditions, it's important to contact your vet immediately if you suspect the disease.

How does Leptospirosis Spread?

Leptospirosis spreads through the urine of infected animals. Wildlife such as raccoons, rats, skunks, and opossums, as well as livestock, can carry and shed the bacteria. The bacteria survive in water and moist soil for weeks or even months. Dogs become infected when bacteria enter through mucous membranes, the mouth, nose, or eyes, or through cuts and wounds, often by drinking from or swimming in contaminated water.

How is Leptospirosis Diagnosed in Dogs?

Diagnosis usually involves blood tests, urine tests, and sometimes imaging such as X-rays or ultrasound to identify signs of infections and organ damage. The reference blood test is the Microscopic Agglutination Test (MAT), which measures antibody levels against Leptospira. Additionally, PCR testing can also be used to detect the bacteria in a dog's blood or urine.

Because recent vaccination can affect antibody test results, your veterinarian will consider your dog’s vaccination history, symptoms, and other test findings together. If leptospirosis is strongly suspected, treatment may begin before all test results are available.

How is Leptospirosis Treated in Dogs?

Dog leptospirosis treatment combines antibiotics with supportive care. Doxycycline is commonly used as the main antibiotic for leptospirosis in dogs and is typically given for around two weeks. If a dog cannot initially tolerate doxycycline, your veterinarian may begin with another antibiotic before switching to doxycycline.

Dogs with more serious illness may need hospitalization, IV fluids, electrolyte management, anti-nausea medication, and additional treatment for kidney or liver complications. Many dogs can recover with prompt veterinary care, although severe cases may be life-threatening or result in lasting organ damage.

How Can I Protect My Dog Against Leptospirosis?

Leptospirosis is largely preventable. The leptospirosis vaccine for dogs is one of the most effective safeguards and is generally given as two initial doses 2 to 4 weeks apart, followed by annual boosters. Your veterinarian can recommend when to begin based on your dog’s age and the vaccine used.

Because leptospirosis can occur in urban, suburban, and rural settings alike, vaccination may be recommended regardless of lifestyle. This is especially important for puppies that are still completing their vaccination schedule. Apart from staying on top of your puppy’s vaccinations , you can further reduce the risk by limiting exposure to stagnant water, controlling rodents, and reducing contact with wildlife.

Preventing Leptospirosis in Puppies and Dogs

Leptospirosis is a serious infection, but vaccination, good hygiene, and early veterinary care can all help reduce the risk and improve outcomes. Knowing the signs and acting quickly when something seems wrong can make an important difference, especially because leptospirosis can also affect people. With the right preventive care and awareness, you can help keep your dog protected throughout their life. For more advice on dog health, nutrition, and everyday care, explore the PEDIGREE® blog.