Lyme tests and treatment in dogs: Necessary or not?

Posted March 27, 2014, at 5:07 p.m.
Last modified March 28, 2014, at 12:45 p.m.

My dog Cruiser recently tested positive for Lyme. Though disappointing, this news did not altogether surprise me. He is a 3-year-old Chesapeake Bay retriever with a penchant for outdoor adventure. The very suggestion that I am preparing to go for a walk sets him dancing around me like a half-drunk and joyful, if oversized, pup. He lives for our walks in the woods, trips to the fields and river and especially our forays to the coast, where he swims with the grace of a marine mammal even in the dead of winter.

Although Cruiserʼs dense russet fur is nearly impermeable to water, it is a liability when searching for the telltale miniscule pinpoint of brown that signals a deer tick has taken up housekeeping. Even treating him with Advantix during tick season, he is a prime candidate for exposure to the bacteria many of these ticks harbor, Borrelia burgdoferi, AKA Lyme.

With a positive Lyme titre, the vet gave him the first in the Lyme vaccine series, and Cruiser came home with a month-long course of cyclosporin; I was told these would speed Lymeʼs departure, and that he should return in two weeks for a Lyme booster.

The screening blood test plus antibiotics and vaccine, added about $200 to the bill for the primary reason he was there: surgery to neuter him. I later learned this is just the tip of the iceberg of cost that can be generated in association with Lyme.

I donʼt mind spending money for necessary care, but I like to feel confident in the logic behind that care. My background is in wildlife biology with a focus on the deer family and brainworm, and primary care medicine, with a focus on prevention and wellness.

This foundation allows me to distill relevant facts from scientific literature, and to distinguish those facts from less straightforward assertions sometimes used to popularize treatments and interventions of questionable benefit.

Paired with my philosophy when it comes to health care, be it for my dogs or myself, that “less is best,” I look for the reason to the rhyme and make up my own mind about what care is necessary. Generally I do as little as possible in the way of tests, medications and procedures, relying on an evidence-based perspective for guidance.

Evidence-based medicine is a phrase we hear a lot these days. It means that decisions and recommendations are derived from independent (as opposed to biased or profit driven) research that demonstrates reproducible conclusions. We can all think of health care recommendations for humans that have gone by the wayside once evidence of their lack of benefit —and potential harm — becomes widely disseminated.

For dogs, one that comes to mind is the rabies vaccine. Formerly mandated as a yearly necessity, research demonstrated that after the first shot, subsequent boosters remain effective for three years or longer, so why require the inoculation at closer intervals when there is a potential risk of deadly injection-site cancers? Doing so is a perfect example of overkill, figuratively — and tragically — in some cases literally!

Yet it took some time to get the Maine law changed even in the face of this irrefutable evidence-based research. One would like to think those in the medical professions would not allow profit motive to cloud what is in the best interests of their patients, but truth be told, this happens.

Lack of knowledge, embarrassment and fear often contribute to accepting unnecessary medical treatment, or over-treatment, and this drives up the cost of medicine and veterinary care. Informed consent, a discussion of the pros and cons of care or treatment, or lack thereof, is what keeps the playing field more even. Better decisions are made when all the cards are on the table.

I didnʼt quite follow the explanation I received about Cruiserʼs positive Lyme titre and the need for treatment, thus I set out to learn more on my own. What I read about Lyme was eye opening. I share my findings here because there is a lot of confusion about Lyme in dogs and I know there must be other dog owners scratching their heads about this condition and what to do.

The first question I sought to answer was, “What exactly does it mean when a dogʼs Lyme titre is positive?” Does he or she have “Lyme disease”? Here is what I learned: A positive Lyme titre in a dog who has never received the Lyme vaccine means the dog has been bitten by a deer tick carrying the Lyme pathogen, Borrellia burgdoferi. These are transferred to the dogʼs blood, an infection that triggers an immune response. The positive Lyme titre means a dogʼs immune response recognized the foreign pathogen and produced antibody against these bacteria. It does not mean automatically that the dog has Lyme disease. “Lyme infection” is NOT the same as Lyme disease. Lyme infection simply means the dog has been exposed to Lyme through a tick bite. I believe here is where the waters have been made murky in communicating these concepts.

In dogs experimentally infected with Borellia burgdoferi, of every 100 dogs to receive the bacteria, 95 of them showed absolutely no clinical signs of illness for the studyʼs duration. Their blood work evidenced a positive immune response to the Lyme bacteria and that was all. The five remaining dogs developed arthritic-like lameness manifesting as swollen, tender and sometimes warm joints that onset spontaneously absent any known injury. Some were less active with decreased appetites. It can be said these dogs have Lyme disease. When treated with a month long course of cyclosporin, the lameness/arthritis resolves within a couple days, and no further treatment is necessary.

Most dogs who develop the lameness and who are not treated with antibiotics get better on their own, but a very small percentage will go on to incur a complication that can result in premature death. This complication is an autoimmune kidney response similar to human glomerulonephritis (damage to the filtering tubules in the kidneys), which can be a complication of an untreated strep infection. Dogs who have this type of kidney complication triggered by untreated Lyme disease have abnormal levels of protein in their urine. Unfortunately, at this point the disease can reach an acute phase very rapidly that results in kidney failure and death. The percentage of dogs who are infected with Borrellia burgdoferi and develop this —or any other — complication is extremely small.

The first thing I took away from this information is that Lyme disease in dogs is quite different from the dreaded Lyme disease in humans. Second, a Lyme positive blood test is not reason to panic and rush to treatment. The vast majority of dogs exposed to Lyme are not sick, and will not get sick.

The next question I sought an answer to was, “Does a Lyme positive dog like Cruiser need to be treated if he has never exhibited the symptoms of arthritis or lameness?” In these cases there is no compelling scientific evidence for initiating antibiotic therapy.

There is nothing to “cure.” Again, the positive titre simply indicates that he was exposed and his bodyʼs own defenses fought off any ill effect.

Down the road, it is minutely possible Cruiser could develop lameness which is the signal the Lyme bacteria have settled into his joints, but at that point, a month-long course of cyclosporin would effectively treat these symptoms. Therefore, it is not necessary for a lyme-positive dog who has not exhibited lameness to immediately receive antibiotic therapy. Likely it will not hurt the dog to get the antibiotics at this point, but one should understand they are not medically indicated from an evidence-based perspective.

The third question I wanted to answer was, “Does my dog really need the Lyme vaccine, a series of shots?” The answer I arrived at is no. The Lyme vaccine only exposes a dog to Lyme so that the dog develops antibody to fight against these bacteria if later exposed to them through a tick bite. Cruiser already had been exposed and his body produced antibody on its own, a normal, healthy immune response. Lyme vaccine would be redundant, another case of overkill like administering rabies vaccine at yearly intervals.

At this point I believe it is fair to say that many veterinarians will argue that much is still not known about Lyme in dogs, and better to play it safe by treating and vaccinating the dog. All kinds of rationales are used to go this route but again, I like to stick to known facts, not possibilities. Thus I decided to stop the antibiotic therapy, and I declined the next in the Lyme series, feeling confident I was doing the right thing for my dog.

If your healthy dogʼs vet recommends your dog receive the Lyme vaccine, you can decline this offer if you prefer not to overload with unnecessary vaccinations.

Remember, if your dog is exposed to Lyme in nature, chances are there will be no ill effects. But should your dog incur Lyme disease from this exposure, symptoms of lameness will signal the illness, and you can get cyclosporin from the vet or online to treat the symptoms. If your unvaccinated dog is tested for Lyme and the titre is positive, (they have a dual test for heart worm, so itʼs hard to avoid the blood test), absent clinical symptoms of the disease, you can treat your dog with cyclosporin or you can decline treatment, and neither decision will be wrong.

I hope this information will help you to make informed decisions about your dogʼs care. Just as you do not have to follow every bit of advice a doctor gives you, you do not have to follow every bit of advice the vet prescribes. Knowledge is key to making informed decisions for your dogʼs health care, and objective understanding of what is known about Lyme in dogs can help you decide what is best for your dog and for your pocketbook. In these times when many of us are cash strapped, this is one case where the decision to decline a recommendation because you simply canʼt afford it, or due to differing philosophies, can be made confidently and without a feeling of inadequacy, embarrassment or guilt.

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