Side Effects of Leptospirosis Vaccine for Dogs

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Leptospirosis is a potentially life-threatening bacterial disease that affects the kidneys and liver of your dog. Your dog can contract the disease from infected urine and contaminated water and soil. There is a vaccine that can help to protect your dog from infection, but as with any vaccine, there are some risks of leptospirosis vaccine side effects. Consider the pros and cons of the leptospirosis vaccine to decide what is best for your dog.


Dogs can get leptospirosis from drinking contaminated water.
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Leptospirosis vaccine safety considerations

The leptospirosis vaccine is not a core vaccine required for all dogs, so you should discuss the benefits and risks of the vaccine with your veterinarian. In many cases, vets will only recommend the vaccine if your dog is at risk of contracting lepto.


Leptospirosis is a bacterial disease that affects mammals, including dogs and humans. Rodents and other small mammals such as raccoons are common carriers of the disease. When infected animals urinate, the bacteria can survive in the contaminated soil and water for months. When your dog walks through or sniffs a contaminated area or drinks contaminated water, he may get infected.


There are many types, or serovars, of the bacteria, and the current vaccine protects your dog from the four most common serovars. Previous generations of the vaccine only protected against two serovars and were associated with more severe side effects including corneal edema. However, the current vaccine has a lower risk of side effects that is comparable with the risks of other vaccines.


Raccoons are a known carrier of leptospirosis.
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Lepto vaccine dangers

Leptospirosis vaccine side effects, if they occur, are usually mild. The most common reaction is lethargy and loss of appetite for a couple of days following vaccination. A skin rash may also appear and you may notice this on the skin where your dog doesn't have hair.


The lepto vaccine is often given at the same time as your dog's other vaccinations, so you may also see side effects common to all vaccines. These include mild swelling and discomfort at the injection site and a mild fever. Reach out to your vet if these symptoms last longer than two days.


Some dogs may have an allergic reaction to the vaccine and have symptoms of anaphylactic shock. West Highland white terriers and miniature dachshunds are at a higher risk for this reaction. Symptoms to watch out for include vomiting, diarrhea, swelling of the face, difficulty breathing, hives and collapse. An allergic reaction is an emergency situation and your should contact your vet immediately if you notice these symptoms.


Small breeds, such as West Highland white terriers, are more likely to have an allergic reaction to vaccines.
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Preventing and treating leptospirosis

Leptospirosis can be a very serious disease that can ultimately cause kidney and liver failure. Initial symptoms may include fever, vomiting, lethargy, loss of appetite, increased thirst and increased urine. Some dogs may be jaundiced. Younger, unvaccinated dogs are more likely to experience severe symptoms. Lepto is treated with antibiotics and early diagnosis and treatment are important to prevent serious organ damage.


Vaccinating your dog against lepto will help to prevent infection, but it is not foolproof. The vaccine protects against the most common types of bacteria but does not cover them all. Vaccinated dogs that do get infected tend to have milder symptoms. In addition, the vaccine only offers short-term protection, so your dog will need to be vaccinated annually after the initial two-dose series.

Take steps when exercising your dog outdoors to prevent his exposure to the bacteria. Don't allow your dog to chase or come into contact with rodents or small mammals. Bring clean water for your dog to drink and avoid allowing him to drink or walk through standing water or mud that may be contaminated with the disease.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.