Lyme disease is caused by infection with Borrelia burgdorferi bacteria that are transmitted through the bites of certain types of ticks (e.g., deer or Ixodes ticks). Lyme disease most commonly affects dogs in the northeastern United States. Humans and other species of animals can develop Lyme disease, but only by being bitten by a tick that carries the bacteria, not through exposure to an infected dog.
Symptoms of Lyme disease can vary depending on where the infection develops in the body, but swollen lymph nodes and painful joints are typical. Kidney disease may also develop with long-term exposure to the bacteria. The "bulls-eye" rash that is associated with Lyme disease in people is not frequently reported in dogs. A veterinarian can diagnose Lyme disease based on a dog's history, clinical signs, physical exam, blood tests that reveal exposure to the Borrelia bacteria, and x-rays or lab tests that can help eliminate other potential causes of a dog's symptoms. Infected dogs will often develop clinical signs long after being bitten by a tick, so a lack of recent tick exposure does not rule out a diagnosis of Lyme disease.
Once a dog has been diagnosed with Lyme disease, treatment with certain types of antibiotics can very quickly improve its condition. Antibiotics do not completely eliminate the bacteria from a dog's body but will suppress the disease to the point where it should not cause any future problems, although future kidney disease remains a possibility. Many cases of Lyme disease can be prevented through the use of effective tick control products. Preventative vaccines are also available for dogs at high risk for developing Lyme disease.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008