Angry Vet On Leptospirosis: Sandy’s Untimely Death

As a sad reminder of leptospirosis’s reality, we had two cases of acute renal failure in otherwise healthy young dogs. 

One of these dog’s kidneys completely shut down and would not respond to treatment. Consequently, we had to euthanize her. The other dog has responded and is now home and expected to make a full recovery.

I dedicate this post to Sandy, our unfortunate patient who died far too young:

Angry Vet On Leptospirosis

Acute kidney failure in dogs and leptospirosis

A differential that is high on the list when an acute renal patient presents is leptospirosis.

Leptospirosis is a bacteria that affects primarily dogs that drink contaminated water. It spreads with the urine of infected rodents and mammals like raccoons.

Once infected, your dog can become sick, sometimes gravely sick, with kidney and/or liver failure.

Symptoms can include

  • drinking and urinating excessively progressing to scant or no urine production
  • vomiting
  • anorexia
  • and lethargy

Leptospirosis treatment

Response to antibiotic therapy is possible if instituted early.  However, the treatment might fail if:

  • the dog receives treatment too late
  • the bacterial strain is resistant to anbitiotics

Under those circumstances, progressive organ failure can lead to death. I also have to note that leptospirosis is contagious to humans too.

Our recent exposure to this bacteria re-raises some of the questions with which we frequently wrestle. 

To vaccinate or not to vaccinate

While we do carry the leptospirosis vaccination, we don’t recommend it as one of our core vaccines.

For dogs who have exposure to wildlife, the benefits of the vaccination might outweigh the risks. The leptospirosa vaccination typically contains four (at least) serovars/strains. 

Scanning electron micrograph of Leptospira interrogans serovar copenhageni.
Image: Medical Books Online

Serovar challenge

The problem is that there are hundreds of serovars. Immunity against one serovar does not necessarily predict immunity against another.

In theory, the selected strains are strains that are known to occur in a local area. This is similar to the human flu shot. In this case, scientists try and predict which flu strain will be out during a particular season. Subsequently, it determines which strain(s) they include in the vaccination. However, these predictions often fall short in providing protective immunity.

Canine leptospirosis vaccinations don’t change with such frequency, so we can expect vaccination immunity to fall short.

Lasting immunity challenge

At the same time, the immunity any strain is fleeting (sometimes 9 months or less). This is because the immunity from bacterial vaccinations is different from the immunity from viral vaccinations.

The vaccine activates various cell-mediated immunity pathways (natural killer cells, etc.) . However, it doesn’t trigger humoral immunity (antibody production) activated by viral vaccines.

Also, and perhaps most importantly, the leptospirosis vaccination is most frequently associated—anecdotally—with vaccine reactions in the patient.  

These reactions are sometimes severe and can necessitate emergency treatment.  Reports of death, while rare, can occur.

Leptospirosis testing reliability

One of our patients, the one who died, tested NEGATIVE for leptospirosis.  

A negative test does not guarantee that he did not have it. The tests can provide false negatives. Interestingly, this dog received leptospirosis recently. This means that either the vaccination failed or that her renal failure was caused by something else. Contaminated dog food from China remains a distinct possibility.

The other dog, who tested POSITIVE for the disease, was not vaccinated.  

A positive test does not guarantee that she had an active leptospirosis infection that triggered her renal failure. The test can also show false positives. The likely scenario is that leptospirosis was indeed responsible for her renal and hepatic failure. She is, fortunately, making a nice recovery.

With all of that said, vaccinations can be very effective biological weapons against disease.  When one determines whether to use a particular vaccine they should ask …

  1. How effective is the vaccine?
  2. Is the vaccine safe?
  3. How long-lasting is the immunity that is conferred by the vaccine?
  4. How likely is it that the dog will be exposed to the disease given their lifestyle?


Leptospirosis is a very difficult vaccination to weigh in on. 

In some heavily endemic areas, where outbreaks are frequent, recommending the vaccine may be much more clear-cut. Conversely, if a dog is paper trained or is indoors (or mostly indoors), the decision to not vaccinate may be easier.  It has been suggested that certain breeds like Dachshunds are more susceptible to reactions.

In my particular area of Long Island and Queens, we do see some outbreaks. 

We offer the vaccine to new patients. We provide the vaccine safety and efficacy information to the owners. This allows people to make their own decision for their own dog.

I do not personally vaccinate my dogs against leptospirosis. As data changes so too may our recommendations.

Related articles:
Canine Leptospirosis: Your Dog and Leptospirosis Infection
Canine Leptospirosis Vaccination Decisions: Traveling and the Return of the Vaccination Dilemma

Further reading:
Bacterial Infection (Leptospirosis) in Dogs

Categories: Leptospirosis

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Dr. Robert Foley

Dr. Foley attended Cornell University’s School of Agriculture and Life Sciences, where he first met his friend, Dr. Michael Ferber. Dr. Foley graduated in 1992 and stayed in Ithaca after graduation to continue working in Dr. Alan Nixon’s laboratory at the NYS College of Veterinary Medicine. Together they studied the efficacy of chondrocyte implantion to treat osteoarthritis and osteochondritis dissecans (OCD) lesions in horses. In 1994, Dr. Foley was accepted into the NYS College of Veterinary Medicine at Cornell University. Dr.’s Ferber and Foley were reunited in vet school and became roommates. Dr. Foley graduated in 1998 and moved to Brooklyn, NY where he practiced for two years. Subsequently, Dr. Ferber invited Dr. Foley to come work with him at his family-owned practice, The North Shore Animal Hospital, in Bayside, Queens, and the two were reunited one last time. After two more years Dr. Foley became a partner within the group. The group decided to open up a new practice together on Long Island. Dr. Foley took a leading role in directing and growing this practice which became South Bellmore Veterinary Group. Over time the practice outgrew its original footprint and today operates as a beautiful, multi-doctor, 5000 square foot, state-of-the art, fully functioning animal hospital. Dr. Foley continues his role as Director of Medicine and Surgery of the practice today. His particular interests include dermatology, soft tissue and ophthalmic surgery. Dr. Foley is passionate about educating his clients on issues such as over-vaccination and the dangers of early spay and neuter.

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