The leptospirosis vaccine is one of the necessary vaccines for dogs so; every dog should get a shot for the leptospirosis vaccine. The current vaccine of leptospirosis is effective and provides immunization for almost 12 months. But, little every vaccine, the leptospirosis vaccine, has some side effects.

Pioneer leptospirosis vaccines were reported to have higher risks or side effects than other common vaccines for dogs. But the current version of the leptospirosis vaccine is safe, and there is no report of death with the current version of the vaccine. Moreover, mild side effects like lethargy, vomiting, and diarrhea are present.

Leptospirosis is a crucial disease in dogs. Leptospirosis could be fatal if left untreated. To know more about leptospirosis, read the following document. We will be seeing available vaccines for leptospirosis, its mode of action, and its possible side effects.

How does Leptospirosis Vaccine Work in dogs?

There are a total of four serovars of leptospirosis-causing bacteria. Four serovars mean the bacteria can interact with the immune system of the host in four different ways. The pioneer vaccine of the bacteria used to provide immunization for two serovars, but now the vaccine has the potency to provide immunization against all four serovars of the bacteria.

Like all the vaccines, the leptospirosis vaccine also contains dead attenuated bacteria. When administered, the leptospira vaccine causes mild diseases in the dog, but the ailment is mild, and it only triggers the immune system of the dog to make antibodies against the bacteria. After the first shot, the second dose of vaccination boosts the immune system and produces sufficient antibodies against the virus. Annual booster injection of the disease is also necessary for the same purpose.

In dogs, the leptospirosis vaccine is administered in the subcutaneous tissues. In some dogs, mild swelling occurs after the administration of the vaccine. This inflammation becomes better after some time. However, if it doesn’t, then you can contact your veterinarian.

 Can Leptospirosis Vaccine Cause Death in dogs?

A century ago, research was done on the guinea pig for the development of the leptospira vaccine. After the successful experiment, the first vaccine was introduced to prevent leptospirosis infection. The earlier vaccine of the bacteria is used to provide immunization against two serovars only, and that vaccine also has several potentially harmful effects. The current vaccine is the improved version of the past, and it has the minimum side effects.

dead dog on floor

But still, like all the vaccines, the Leptospirosis vaccine also causes mild side effects. The side effects of the vaccine are:

  • Mild swelling at the injection site
  • Lethargy and tiredness
  • Some dogs also develop a mild fever.

Dogs often feel discomfort and uneasiness after the administration of the vaccine. This discomfort lasts for two days, maximum. If it is prolonged, then you should contact a veterinarian for help.

Serious side effects are rare. There is only a 0.4% to 0.6% risk of the harmful effect of the vaccine. Harmful effects of the vaccine include:

  • Depression, dyspnea
  • Vomiting, diarrhea
  • Allergic reaction such as urticaria (urticaria or hives is the most common type of the vaccine, it is also the immediate type of reaction in dogs)
  • Hypertension

These are some most common side effects of the leptospirosis vaccine. However, there could be specific signs of vaccine reaction like; aggressive behavior, anorexia, laziness, and lack of interest. Above this, there are no side effects of leptospirosis infection. And also, no death has been reported so far with the current vaccine. In other words, we could say the leptospirosis vaccine doesn’t cause death in dogs.

The side effects or harmful effects of the vaccine start to appear immediately after the administration, it rarely takes more than a day. According to researchers; the leptospirosis vaccine occasionally causes a reaction in young dogs and small-breed dogs (the reason is unknown). And also, if vaccination of more than one disease is done on the same day, we can see side effects. So, avoid shots of two different vaccinations simultaneously. In fact, in young animals, one should not administer the leptospirosis vaccine with any other vaccine, because it can cause several side effects.

Vaccine reaction is easy to control. If your dog faced a mild or severe vaccine reaction, then before the second shot of the vaccination, inform the doctor about the previous effects. By seeing the history, a veterinarian can medically control the side effect of the vaccine.

What is Leptospirosis anyway?

Leptospirosis is a zoonotic disease caused by the Leptospira genus of bacteria. Leptospira is a twisted type of bacterium, morphologically it is tightly coiled. Leptospirosis is an obligate aerobic spirochete organism, moves with flexuous movement and has over 200 serotypes. Leptospira primarily attacks the dog’s kidney and then liver and hinders their normal functioning. Occasionally some dogs also develop respiratory and bleeding abnormalities. The disease is zoonotic, which means your infected dog can transfer it to you and vice versa. Dogs mostly get the leptospira infection from the direct contact of soil and water, contaminated by the urine of wildlife animals.

leptospirosis vaccine

All breeds of dogs can get the leptospira infection, but herding dogs, hounds, and working dogs are at higher risk. It is because they are more exposed to the potential cause than others. The spread and prevalence of the disease are variable in different parts of the world. But the leptospira genus of bacteria prefers a moist environment. Bacteria can stay in a moist environment for more than a year. That is why in most countries, its outbreak occurs in the late summers and the early fall.

Direct dog to dog transmission is rare. However, a dog can be infected in any season if its mucous membranes or skin with any wound come into contact with:

  • Infected urine
  • Urinated water
  • Urine-contaminated Food
  • Urine-contaminated Soil
  • Through a bite from an infected animal
  • Eating infected tissues or carcasses.

Pet owners mostly get leptospirosis infections from their pets during recreational activities. Now let’s see why leptospirosis infection is harmful to dogs?

How Leptospirosis Infection is Harmful to dogs?

Leptospirosis is one of the crucial diseases or infections for dogs. It can affect a dog’s health in multiple ways. The bacteria after entering the body proliferate and attack the dog’s immune system. These bacteria cause inflammation of various organs, like severe inflammation of the eyes, kidney, and liver.

Sometimes crucial kidney infection can lead to kidney failure, same as the cause with the liver. Frequently these bacteria attack the lungs and cause severe respiratory diseases. Leptospirosis can also cause a bleeding disorder. Infected dogs may pass feces and urine containing blood, and blood-tinged vomit and saliva are also found during the leptospira infection.

What are the Signs of Leptospirosis in dogs?

Signs and symptoms of leptospirosis can vary in dogs of different breeds, health status, and age, but some symptoms are present in every dog infected with the leptospira genus.

dog tired

Initial Signs of Leptospirosis

The incubation time of the bacteria is about 7 days. 7 days incubation period means the signs and symptoms of the disease will become evident after the 7 days of exposure to bacteria. Early symptoms of the infection are not severe, and also the differential diagnosis of the early disease is difficult because signs and symptoms are not critical. The initial signs of the disease are:

Fever with shivering

The exact figure of the fever is variable. We think that it depends on the immune status of the dog. Shivering is also a common sign of early infection.

Muscle tenderness

Muscles of the infected dogs become stiff. The infection can make your active dog dull and reluctant to move.

Increased thirst

A marked increase in thirst is seen in dogs during the early days of infection. Diarrhea and dehydration are also common.

Late Signs of Leptospirosis

Late signs are the crucial signs of diseases. Late signs of leptospirosis can pose a life-threatening condition in dogs. The most common late signs of the disease include.

  • Kidney failure
  • Liver failure
  • Edema of the chest and abdomen also called ascites
  • Discharge of blood through urine, feces, vomit, saliva, and also from nose
  • Swollen legs due to fluid accumulation
  • Lung diseases and difficulty in breathing
  • Anorexia and jaundice is also common

The span and severity of the signs and symptoms are also variable among dogs. Some dogs develop very transient and mild symptoms of the disease, while others develop significant symptoms, and these symptoms sometimes put the life of the dog at risk.

What is the Treatment of Leptospirosis?

Treatment of leptospirosis is possible with the help of antibiotics and vaccines. The disease is easy to prevent and treat in the initial stages of the disease. One can easily control the early stages of the disease with the help of antibiotics. But make sure to consult a veterinarian before using any antibiotic for the dog.

The favorable treatment for the infection is the vaccine. In 1960, the first vaccine was introduced against leptospirosis infection. Since then, vaccination is in use to prevent the dogs from the disease. Vaccination is one of the best ways to save the dog from bacteria. The available vaccine can provide immunity for almost 12 months.

The vaccination of leptospirosis is administered as a series of two injections at an interval of 14-28 days. After traditional shots of vaccination, an annual booster shot is also needed for better immunity. Leptospirosis is very common among dogs, so every dog, either exposed or unexposed should get the vaccination as a prophylactic. It is recommended not to vaccinate your pup against leptospirosis at a very young age. 8-9 weeks is the ideal age for a pup to get a shot of leptospirosis vaccination.

Along with vaccination, prevention is also essential. Prevention is the key if you want to save your dog from the deadly zoonotic bacteria, and then you need to monitor your dog. Avoid the wildlife exposure of your dog. Also, if your dog loves to wander around, then try to administer a prophylactic vaccine.


Leptospirosis is an important disease in dogs. If left untreated it can cause several health issues in dogs. Leptospirosis is a very common disease for dogs who frequently go out. Initially, the vaccine had many side effects. But the present vaccine of leptospirosis is safe and effective, and there are not any severe side effects of it. And also vaccine shots of leptospirosis don’t cause death in dogs. Moreover, it is possible to reverse the side effects of the vaccine medically.


Q. 1 Only large male dogs, or dogs that go out, frequently are susceptible to leptospirosis?

Any age, sex or breed, of dog is susceptible to infection of leptospirosis. And also, the decision of vaccination shouldn’t be made based on lifestyle. Instead, the decision should be made, after seeing the risk of exposure. If a 0.1% risk of exposure is available, then the vaccination should be done.

Q.2 Leptospirosis vaccine is not safe and can cause death in dogs?

The newer leptospirosis vaccine is safe and effective, and it protects dogs against 4 serovars of Leptospira. And the vaccine hasn’t caused mortality in any dog until yet. However, the severe side effect of the vaccine includes severe hypersensitivity or hives.

Q.3 One vaccine dose is enough to provide lifelong immunization?

First of all, two shots of vaccination are necessary to prevent the initial infection. Initial two doses provide effective immunity only for 12 months. After that, an annual booster vaccine is necessary to maintain consistent immunity.

Q.4 Does the leptospirosis vaccine provide immunization against all the serovars of the bacteria?

There are 250 serovars of Leptospira and more than 22 species. The current vaccine provides immunization against only four serovars of bacteria. The four serovars that are sensitive to the vaccine are the most common serovars of the dogs. So the vaccine can produce immunization of bacteria in dogs.