Lyme disease in dogs is one of the most common tick-transmitted diseases in the world, but it only causes symptoms in 10 percent of affected dogs. When infection leads to Lyme disease in dogs, the dominant clinical feature is recurrent lameness due to inflammation of the joints, and a general feeling of malaise. There may also be depression and a lack of appetite. More serious complications include damage to the kidneys, and rarely, heart or nervous system disease.
Transmission of Lyme disease has been reported in dogs throughout the United States and Europe, but is most prevalent in the upper Midwestern states, the Atlantic seaboard and the Pacific coastal states. However, the disease is spreading and becoming more common throughout the United States.
Symptoms of Lyme Disease in Dogs
Many dogs who develop Lyme disease have recurrent lameness due to inflammation of the joints. Sometimes the lameness lasts for only three to four days but recurs days to weeks later, either in the same leg or in other legs. This is known as “shifting-leg lameness.” One or more joints may be swollen, warm and painful.
Some dogs may also develop kidney problems. Lyme disease sometimes leads to glomerulonephritis—inflammation and accompanying dysfunction of the kidney's glomeruli (essentially, a blood filter).
Eventually, kidney failure may set in as the dog begins to exhibit such signs as vomiting, diarrhea, lack of appetite, weight loss, increased urination and thirst, and abnormal fluid buildups.
Other symptoms associated with Lyme disease in dogs include:
- Stiff walk with an arched back
- Sensitivity to touch
- Difficulty breathing
- Fever, lack of appetite, and depression
- Superficial lymph nodes close to the site of the infecting tick bite may be swollen
- Heart abnormalities are reported, but rare
- Nervous system complications (rare)
Causes of Lyme Disease in Dogs
Lyme disease is caused by a spirochete (bacteria) of the Borrelia burgdorferi species. Borrelia burgdorferi is transmitted by slow-feeding, hard-shelled deer ticks (Ixodes spp.). Infection typically occurs after the Borrelia-carrying tick has been attached to the dog for at least 48 hours.
Diagnosing Lyme Disease in Dogs
You will need to give a thorough history of your dog's health to give your veterinarian clues as to which organs are being affected. Your veterinarian may run some combination of blood chemistry tests, a complete blood cell count, a urinalysis, fecal examinations, X-rays and tests specific to diagnosing Lyme disease (e.g., serology). Fluid from the affected joints may also be drawn for analysis.
There are many causes for arthritis, and your veterinarian will focus on differentiating arthritis initiated by Lyme disease from other inflammatory arthritic disorders, such as trauma and degenerative joint disease. Immune-mediated diseases will also be considered as a possible cause of the symptoms. X-rays of the painful joints will allow your doctor to examine the bones for abnormalities.
Treating Dog Lyme Disease
If the diagnosis is Lyme disease, your dog will be treated as an outpatient unless their condition is unstable (e.g., severe kidney disease). Doxycycline is the most common antibiotic that is prescribed for Lyme disease, but other dog antibiotics are also available and effective.
The recommended treatment length is usually at least four weeks, and longer courses may be necessary in some cases. Your veterinarian may also prescribe an anti-inflammatory (pain medication for dogs) if your dog is especially uncomfortable.
Unfortunately, antibiotic treatment does not always completely eliminate infection with Borrelia burgdorferi bacteria. Symptoms may resolve but then return at a later date, and the development of kidney disease in the future is always a worry. Proper use of antibiotics reduces the likelihood of chronic consequences.
Living and Management
Improvement in sudden (acute) inflammation of the joints caused by Borrelia should be seen within three to five days of antibiotic treatment. If there is no improvement within three to five days, your veterinarian will want to reevaluate your dog.
Preventing Lyme Disease in Dogs
If possible, avoid allowing your dog to roam in tick-infested environments where Lyme disease is common. Check your dog’s coat and skin daily, and remove ticks by hand. Your veterinarian can prescribe a variety of prescription flea and tick collars, topical and oral products that kill and repel ticks.
Such products should be used under a veterinarian's supervision and according to the label's directions. Lyme vaccines are available, but their use is somewhat controversial. Talk to your veterinarian to see if the Lyme vaccination is right for your dog.