A quick romp in the backyard or a long-distance hike through the woods both mean a good day for most dogs, but lurking ticks in long grass and other vegetation mean we need to be vigilant about post-outdoor fur checks. It’s especially important to catch Lyme disease early in dogs, and to do your best to prevent them from getting it in the first place.
What Is Lyme Disease In Dogs? How Do They Get It?
Infection with the bacteria Borrelia burgdorferi causes Lyme disease1-3. It spreads from host to host through black-legged ticks (deer ticks) after 48–72 hours of attachment1-4. Dogs, cats, horses, cattle, and people can develop lyme disease, but you’ll never see direct transmission from one species to another1.
Tick bites do carry bacteria from one host to the next. Dogs can also bring infected ticks into your home, potentially exposing their household humans. A careful brushing or a good petting session can help find any six-legged stowaways, but take special care to check in their ears, under their collar, and between those corn chip-scented toes.
How Do Ticks Get Lyme Disease?
Ticks become infected with the Lyme disease bacteria by feeding on reservoir hosts (those that carry the disease but don’t show symptoms). White-footed mice are the noted reservoir, but it can also come from other small mammals, birds, and lizards1-2.
Birds can easily spread ticks to areas that previously have not had Lyme disease1. Below are the current CDC maps for the two ticks responsible for spreading Lyme disease in the US—the black-legged tick (deer tick, Ixodes scapularis) and western black-legged tick (Ixodes pacificus).
What Does Lyme Disease Look Like In Dogs?
Dogs contract 2 well-documented forms of lyme disease: arthritis and renal3.
Arthritis Form Of Lyme Disease
The arthritis form is more common and usually seen in younger dogs. Symptoms include:
- Swollen lymph nodes (lymphadenopathy)1-2
- Swollen joints1-2
- Limping that can change legs1-3
Sometimes these symptoms resolve without intervention, but others require antibiotic treatment3—a small price to pay to get that tail wagging again!
Renal Form Of Lyme Disease
The renal (a.k.a. kidney) form is less common, but very serious because it causes protein-losing glomerulonephritis2-3. This means the kidneys, which usually act as a filter to keep the good and get rid of the bad, become inflamed and can’t do their job as well. As a result, the body loses valuable proteins it needs to function appropriately.
While we don’t understand the exact cause of the renal form of Lyme disease in dogs, we believe immune complexes (“good guy” antibodies bound to “bad guy” antigens) depositing in the kidney2-3 are to blame. Symptoms include:
- Not eating (anorexia)2-3
- Weight loss2
- Swelling of legs (peripheral edema)2
- Free fluid in chest or abdomen (body cavity effusion)1-2
- Difficulty breathing (dyspnea)1
Dogs with this condition are often quite ill and require hospitalization to treat acute renal failure, and most unfortunately don’t survive2. Lyme disease has reportedly caused cardiac (heart), neurologic (brain), and dermatologic (skin) disease, but it isn’t well-documented and quite rare2-3.
I Found A Tick On My Dog. How Long Does It Take For Lyme Disease Symptoms To Show?
Dogs bitten by an infected tick typically show symptoms 2–5 months AFTER the tick bite1-3. If you’ve noticed ticks on your dog, seek veterinary care to make sure all ticks have been completely removed, start them on tick prevention medication, and make a plan for your individual dog’s care.
Related Article: How To Remove A Tick From Your Dog
A month after tick exposure, your vet can run tests to determine whether your dog was actually bitten by an infected tick2-4. Even if this is the case, most dogs who test positive (90–95%1,3) remain symptom-free. So don’t panic, but keep an eye out for symptoms of Lyme disease and seek care immediately if they develop.
Vets recommend testing for other coinfections (infections that commonly happen at the same time as Lyme disease) for dogs exposed to ticks or who have had confirmed exposure to Lyme disease-causing bacteria. These include:
- Rocky Mountain Spotted Fever1-3
Head to your vet for routine urine tests if your dog tests positive for exposure to Lyme disease but doesn’t show symptoms1-3. This allows your vet to detect kidney disease early, and hopefully results in a better response to treatment.
How Can I Prevent My Dog From Getting Lyme Disease?
Tick prevention and control is key1,3, and keeping your dog on year-round tick prevention medication that repels or prevents attachment of ticks is ideal3-4. It’s also a great idea to maintain your outdoor landscaping by clearing away long grass, mowing the lawn consistently, and raking leaves to minimize tick habitats in your yard, as well as daily removal of any ticks found on your dog3.
Is There A Lyme Disease Vaccine?
Vaccinations for Lyme disease are available for dogs, but controversial1,3-4. Vaccination works by training the immune system to recognize illness-causing agents in the body. This allows the body to quickly flag (with antibodies), attack, and eliminate the threat before it has a chance to cause illness.
With Lyme disease in dogs, the concern is that the renal form (the very rare but usually fatal form) is likely caused by those antibodies bound to antigens getting into the kidneys, and vaccination may increase the risk of developing the condition2-4. There are no good studies right now to clarify this issue.
If you’re considering getting your dog a Lyme vaccination, discuss it with your veterinarian, as your pup’s individual health and local Lyme disease burden will help you both to make a decision3.
Colleen Ferriman, DVM, is a canine and feline health, wellness, and illness management advocate. She has a combined 10 years of experience in clinical medicine, education, and educational content development. Colleen graduated from Colorado State University as a Doctor of Veterinary Medicine, has worked as a general practitioner, and has contributed to the development of veterinary educational tools. She is also a member of the American Veterinary Medical Association and American Academy of Veterinary Pharmacology and Therapeutics.
1Cote E: Borreliosis. Clinical Veterinary Advisor Dogs and Cats, 2nd ed. St. Louis, Elsevier Mosby 2011 pp. 146-147.
2Rathrock K: Lyme Disease (Zoonotic) (Canine). VINcyclopedia of Diseases 2019.
3Littman MP, Goldstein RE, Labato MA, Lappin MR, Moore GE: ACVIM Small Animal Consensus Statement on Lyme Disease in Dogs: Diagnosis, Treatment, and Prevention. J Vet Intern Med 2006;20:422-434.
4Littman MP: ACVIM Lyme Consensus Update. ACVIM 2018.