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 the 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:

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 bacterial infection spread through the urine of infected wildlife and rodents. Dogs are exposed when contaminated water, mud, or soil contacts their mouth, nose, eyes, or broken skin.

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
• fever or muscle stiffness
• reluctance to move
• yellowing of the eyes or gums (jaundice)
• sudden weakness or collapse

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 antibiotics

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 infection re-raises some of the questions with which we frequently wrestle. 

To vaccinate or not to vaccinate

Leptospirosis vaccination is considered non-core, meaning not every dog needs it automatically. The decision depends on lifestyle and exposure risk.

Dogs that hike, visit parks, swim, drink from puddles or ponds, or live around wildlife and rodents are at higher risk. For those dogs, vaccination often makes good sense.

Most modern vaccines protect against four common serovars responsible for the majority of canine infections. While they can’t cover every strain, there is often some cross-protection between related strains, which can still lessen the severity of disease.

As with any vaccine, mild side effects are possible and serious reactions are uncommon. The best approach is to weigh your dog’s individual risk with your veterinarian rather than follow a one-size-fits-all rule.

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, protection is not perfect because vaccines can’t include every possible serovar.

Vaccines can’t cover every possible serovar, but they target the main serovars known to cause disease locally. While not perfect, they reduce risk significantly—especially in exposed dogs.

Lasting immunity challenge

At the same time, the protection doesn’t last as long as many viral vaccines and is typically boosted yearly.

Leptospirosis vaccines are bacterins (killed bacteria). They do stimulate protective immunity, but that protection doesn’t last as long as many core viral vaccines. That’s why boosters are typically given yearly.

Also, and perhaps most importantly, the leptospirosis vaccination is historically associated with a higher rate of vaccine reactions compared with other vaccines.

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. 

Early in the disease, tests can be negative. Vets often repeat testing or combine PCR and antibody tests because timing affects accuracy.

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.

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 effective tools 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?

Summary

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