by Elizabeth F. Baird, DVM, CVPP, CCRT, CVMA
It may be a rare bacteria, but it is ever-present in Florida. Dr. Baird, of Country Oaks Animal Hospital in Palm Harbor, weighed in on Leptospirosis for The New Barker dog magazine, a year ago in the Spring 2016 issue. It is just as relevant today, as cases of Leptospirosis is rising.
Leptospirosis, a disease common to many mammals, is caused by a type of bacterium called Leptospira. It seems to be on the rise in dogs the last few decades and has shifted from a rural disease to a suburban and even urban problem. Dr. Carsen Brandt of the Emergency and Critical Care Service at the University of Florida’s College of Veterinary Medicine, has reported a tenfold increase in cases since 2013. There have been fairly recent outbreaks in Fresno, California and Denver, Colorado. Dr. Richard Goldstein of the Animal Medical Center in New York City says he sees cases of Lepto every week, including in dogs that have never left Manhattan. So much for the image of this as a rural disease.
A typical scenario goes something like this: A raccoon urinates on the grass in a suburban yard or in a puddle at a park during the night. A dog then sniffs or licks at that curious odor while out for a walk the next day. Bingo! The dog has now been exposed to one of the eight strains of Leptospira bacteria that can cause Leptopsirosis in the dog. The bacteria quickly begin to replicate and move into various target tissues such as the kidneys, liver, spleen and central nervous system. The infected dog typically begins to show signs of illness within 7 days of exposure. The severity of the illness can vary considerably, from mild and vague symptoms to acute kidney failure and fairly sudden death.
So, what other wildlife carry these Leptospira bacteria in their urine? In addition to the ever-present raccoon, mice and rats are common carriers of Leptospira and this includes the ubiquitous wood rats and citrus rats that populate most of Florida. The opossum, skunk, deer, cow and pig can carry other infectious strains of Leptospira bacteria. There is some question as to whether squirrels are also carriers for Leptospira.
If a dog contracts Leptospirosis, what happens next?
Unfortunately, the clinical symptoms of the disease are not very distinctive, making diagnosis trickier. The affected pet will usually be lethargic and have a poor appetite, sometimes showing signs of a fever. The majority of affected animals will have some vomiting and about a third will have diarrhea and weight loss. None of this is terribly specific and it sounds like many other illnesses. Routine lab tests may show significant abnormalities in the urinalysis, as well as the kidney and liver values. None of these are terrifically specific either, but it does start to help narrow the diagnosis list. At this stage, the veterinarian is likely looking to test for Leptospirosis. The older Lepto test can take up to a week and won’t catch every patient. A newer type of test, an Elisa test, can be run right in the hospital in under 30 minutes. It’s still not perfect, but it will detect many patients right away. A patient with these symptoms is likely already on intravenous fluids and medication to help with the vomiting and discomfort. A diagnosis of Leptospirosis indicates a need for very specific antibiotics as not all antibiotics will do the trick. If IV fluid support and the appropriate antibiotics are started in a timely manner, the prognosis is good and most patients (80-plus percent) will recover. If it takes longer to diagnose due to the vague symptoms or a delay in seeking medical care, the dog may suffer kidney failure, but many can still be saved with dialysis.
Did I mention that you can catch Leptospirosis too? Yes, it is actually one of the most common infectious diseases in humans worldwide. Thankfully, it is not common in humans in the U.S., at least outside of Hawaii. The odds of catching it directly from your dog are pretty slim, but if your dog has been diagnosed with Leptospirosis, your vet will give you detailed instructions on methods to protect yourself and family. You are far more likely to catch it from swimming in rivers, streams or walking through swampy water. In 2005, 44 out of 192 adventure racers in Tampa (23% of the participants) caught Leptospirosis from running through swampy water. There was an earlier outbreak in Illinois in Triathlon runners. Dogs can contract it directly from contaminated water as well.
Given the large population of potential wildlife carriers and the difficulty in diagnosing the disease early, prevention is a more prudent approach in the areas where Leptospirosis is a risk. The older vaccines (1970’s and 80’s) carried a higher risk of vaccine reaction and only covered two strains. Because of this, they had fallen out of favor in that era and were used only in the higher risk rural areas. Leptospirosis was labeled a non-core vaccine to use only for “at risk” populations. But the definition of which dogs are at risk seems to have shifted significantly in the last decade or two. The rural outdoor large breed dog that was the poster child for Leptospirosis in 1985 is now a fluffy suburban or urban Shih Tzu or Cocker Spaniel. We currently have Leptospirosis vaccines that protect for four strains. They have a much lower risk of vaccine reaction than the older vaccines – and are more highly purified as vaccine manufacturing technology has evolved over the last 30 years. Some internists believe that even though our current vaccines only cover four of the Leptospira serovars, there may be cross-reactivity and some protection from the other infective strains as well. Leptospirosis is very uncommon in vaccinated dogs, regardless of the strain or serovar of Leptospira bacteria involved. It is a series of two doses given 3-4 weeks apart and then yearly boosters.
If your pet tends to be sensitive to vaccines and you’re worried they may react, have this administered separate from any other injectable vaccines. The more vaccines given in one day, the higher the risk of a vaccine reaction, regardless of which specific vaccinations are given.
Given the changes in Leptopsirosis over the last few decades, from the shifts in which strains are causing disease and the populations of dogs being affected, it is time to rethink our approach to managing this dangerous disease. The vaccines are more protective and less reactive than ever before and our suburban house dogs are at a higher risk than we believed possible even twenty years ago. If your dog is not already protected from Leptospirosis, it may be time for a conversation with your veterinarian about the risk factors in your specific area and whether vaccination is appropriate for your beloved dogs. I can assure you that mine are vaccinated against this potentially deadly disease. Raccoons, opossums and citrus rats are rampant in my suburban neighborhood and the risk of potential exposure is real. And all too scary to ignore.
THE NEW BARKER VETERINARY ADVISORY BOARD INCLUDES: Dr. Elizabeth Baird, Country Oaks Animal Hospital/Palm Harbor; Dr. Mark Brown, Central Animal Hospital/St. Petersburg; Dr. Eddie Garcia, Urgent Pet Care of South Tampa; Dr. Shawna Green, Medicine River Animal Hospital/Madeira Beach; Dr. Timothy Hodge, Harbourside Animal Hospital/Downtown Tampa and Cross Creek Animal Medical Center/Tampa; Dr. Steven Lewis, Davis Island Animal Clinic; Dr. Gregory Todd, Animal Hospital of Dunedin.