After a cold, wet spring, Mother Nature finally decided to take pity on us poor damp mortals. It stopped raining and we actually have seen the sun several times this summer. Hurray! All that rain has made it a horrible year for vegetables and given us a bumper crop of mosquitoes. It also made conditions perfect for an outbreak of leptospirosis in our dogs. What is leptospirosis, you ask? That is a very good question and it is one I frequently get asked. While many clients know about parvovirus or distemper, many have never heard of leptospirosis (or lepto, for short). There is a short little blurb about the disease and the vaccine on our “Canine Vaccination” page, but I would like to go into a little more detail here.
Let me start with the basics. Leptospirosis is a zoonotic disease caused by the spirochete (or spiral shaped) bacteria Leptospira species. Zoonotic means it can be transmissible between humans and animals. There are a variety of subtypes or serovars including Leptospira canicola, L. grippotyphosa, L. icterohaemorrhagiae and L. pomona. It is spread through the urine of infected wildlife (raccoons, opossums, skunks, etc) and can survive in environment for many months or years. Dogs are usually infected through direct contact with an infected animal (bite wounds, ingestion of infected tissues, urine, etc) or indirectly through contaminated water, soil, food or bedding. Does your dog ever dig in the dirt, swim in a lake, or drink from a puddle? Then your dog is coming into contact with potentially contaminated water and soil. All the rain we got this spring made a lot of prime lepto-spreading puddles! Any mammal can be infected including humans, so there is a risk to owners if their dog is a potential lepto carrier.
The signs of leptospirosis can vary. Most commonly reported clinical signs include fever, vomiting, diarrhea, anorexia, weakness, stiffness or severe muscle pain. Hmm. A lot of those symptoms are pretty non-specific, huh? How many of your animals have ever had an episode of gastrointestinal upset? Fever or stiffness? These symptoms can be due to a laundry list of conditions, which can make leptospirosis hard to pin down. When a lethargic, vomiting Labrador comes in, we first want to rule out more likely causes (i.e. he ate some garbage) before pursuing less common conditions like lepto. One of the scary things about this disease is the range of presenting signs and severity. Some patients will present with relatively mild-moderate signs while others can present in shock or even in full-blown liver and/or kidney failure. Yes, you heard me. Lepto can cause liver and kidney failure. Got your attention, didn’t I? Many cases are subclinical, meaning they may not even be noticed or detected, but some dogs can progress to shock and death very quickly. Young dogs also tend to be more severely affected than older, well-vaccinated dogs.
Now, how do we find out if a sick dog has lepto? Well, first there are a number of abnormalities on bloodwork that lead us to add lepto to our suspect list. These include elevated kidney values, signs of dehydration, hemolysis (red blood cell destruction), abnormal electrolyte numbers, and high liver values. Once we suspect leptospirosis, there are several tests that can confirm infection. The most common test is the microscopic agglutination test (MAT). This test looks at antibody titers to the various leptospirosis serovars. A high MAT titer in addition to clinical signs of lepto is highly suggestive of active infection. However, interpreting titers in vaccinated animals or in the early stages of disease can be problematic. It may take several days to weeks for a titer to rise in response to infection. Therefore, a dog may have a low titer in the early stages of disease and need a second sample taken 3-4 weeks later to confirm infection. There are other tests for this disease including ELISA or IFA methods, but these tests can also be difficult to interpret.
Treatment for this disease varies with the severity of clinical signs. Many dogs need to be hospitalized on intravenous fluids and medication until they can be stabilized and their kidney/liver function improves. Penicillins are the initial antibiotic of choice. Prognosis is guarded depending on the extent of organ damage. Potential complications are numerous and may require transfer to an ICU or 24-hour referral hospital. Some dogs will have permanent liver or kidney dysfunction. And because this disease can be transmissible to humans, special care must be taken when handling the patient, its bedding and waste. Thankfully, treatment for this disease can be highly successful if caught early and treated appropriately, however it does require significant dedication on the part of the owner.
Which leads me to my final topic – prevention! Obviously, it is far better to prevent this disease than to treat it. Vaccination is currently available for four types of leptospirosis serovars. We recommend vaccinating puppies starting at 12 weeks of age, boostering 3-4 weeks later and then once yearly. Now, there are a lot .jpg)
of scary (occasionally crazy) stories on the internet about how dangerous this vaccine is and how you should never give it to your dog. Does this vaccine occasionally cause a reaction? Sure, any vaccine can potentially cause a reaction. Does every dog in the world need this vaccine? No, it depends on their health status and potential exposure. Are all of my dogs vaccinated? Yes, every year. Leptospirosis is a serious, potentially deadly disease. The majority of our patients are at risk and therefore, we recommend the vaccine for the majority of our dogs. But there are some dogs that do have vaccine reactions or are at low risk for this disease. Tiny 3lb Chihuahuas that never touch the ground are obviously at low risk! That is why we tailor our vaccine protocols depending on your dog’s age, lifestyle and possible exposure. So please feel free to discuss the potential benefits and risks of any medical decision, vaccine or otherwise, with us when you come in. As I’ve mentioned before, leptospirosis is a scary disease. It can be hard to detect and diagnose. Even if your dog recovers, it can cause permanent organ damage. I would be a very happy doctor if I never saw another case of leptospirosis in my career.
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