Lyme Disease in Dogs

Lyme Borreliosis

Lyme disease is one of the most common tick-transmitted diseases in the world. It is caused by a spirochete (bacteria) species of the Borrelia burgdorferi group. Dominant clinical feature in dogs is recurrent lameness due to inflammation of the joints. There may also be a lack of appetite and depression. More serious complications include damage to the kidney, and rarely heart or nervous system disease. Kidney disease appears to be more prevalent in Labrador retrievers, golden retrievers, and Bernese Mountain dogs. Experimentally, young dogs appear to be more susceptible to Lyme disease than adult dogs. Transmission of the 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.

Causes

• Borrelia burgdorferi transmitted by slow-feeding, hard-shelled deer ticks
• Infection takes place only after a tick (nymph or adult female) carrying Borrelia has been attached to the host for at least 18 hours

Symptoms and Types

• Recurrent lameness due to inflammation of the joints
• Sudden (acute) form lasts for only three to four days but recurs days to weeks later, with lameness in the same leg, or in other legs; known as “shifting-leg lameness,” this condition is characterized by lameness in one leg, with a return to normal function, and another leg is then involved; one or more joints may be swollen and warm; a pain response is elicited by feeling the joint; responds well to antibiotic treatment
• Long-term (chronic) inflammation of several joints, in which the bones around the joints are not destroyed, is found in animals that have suffered prolonged infection without adequate treatment; may persist despite antibiotic therapy
• Affected dogs may walk stiffly with an arched back and may be sensitive to touch.
• Fever, lack of appetite, and depression may accompany inflammation of the joints
• Superficial lymph nodes close to the site of the infecting tick bite may be swollen
• Kidney damage – glomerulonephritis – reported with immune-complex deposition in the glomeruli leading to fatal kidney disease; each kidney is composed of thousands of nephrons (the functional units of the kidney, each consisting of the glomerulus [a tuft of blood capillaries – the blood filter] and a series of tubes and ducts, through which the filtered fluid flows as urine is produced; where glomerulonephritis is inflammation and accompanying dysfunction of glomeruli (plural of glomerulus) of the kidney
• Kidney failure - signs include vomiting, diarrhea, lack of appetite, weight loss, increased urination, and increased thirst, fluid build-up in the tissues, especially the legs and under the skin, or fluid build-up in the abdomen
• Heart abnormalities are reported, but rare; they include complete heart block
• Nervous system complications are rare

Diagnosis

You will need to give a thorough history of your dog's health, including a background history of symptoms, and possible incidents that might have precipitated this condition. The history you provide may give your veterinarian clues as to which organs are being affected secondarily. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. Your veterinarian will use these tests to look for the presence of bacteria, parasites, and fungi in the bloodstream. Fluid from the affected joints may also be drawn for analysis.

The condition of the skin near the tick-bite site will be an important indicator of your dog's health as well, such as whether the wound is still open, or whether there are any fragments of the tick's body left in the wound.

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, or osteochondrosis dissecans (a condition found in large, fast growing breeds of puppies). Immune-mediated diseases will also be considered as a possible cause of the symptoms, and an x-ray of the painful joints will allow your doctor to examine the bones for damage or disorder.

Treatment

If the diagnosis is Lyme disease, your dog will be treated as an outpatient, unless its health condition is severe. There are a number of antibiotics from which to choose. It is important that you keep your dog warm and dry, and you will need to control its activity until the clinical signs have improved. The recommended period for treatment is four weeks. Your veterinarian is unlikely to recommend dietary changes. Do not use pain medications unless they have been recommended by your veterinarian. Long term joint pain may continue even after the bacteria has been fully eradicated from your dog's system.

Prevention

• Avoid allowing your dog to roam in tick-infested environments where Lyme borreliosis is common (known as an endemic area)
• Mechanical removal of ticks – groom your dog daily; discuss appropriate techniques for the removal of ticks with your veterinarian
• Prevention of tick attachment – sprays and collars, products used to kill ticks and tick repellents are available commercially as spot-on topical products; such product should be used only according to label directions
• Vaccines are available commercially for dogs; talk to your veterinarian about its availability and whether it is right for your dog
• Control the tick population in your environment if your pet is restricted to small areas; you may have limited success by reducing deer and/or rodent population

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 consider a different diagnosis. Treatment of Lyme disease requires regular administration of antibiotics as prescribed by your dog's veterinarian. The disease may recur, with intervals of weeks to months, with a positive response to antibiotic treatment each time.