Lyme disease

Lyme disease is an illness transmitted through a tick bite. A tick can infect both humans and dogs; in this article, we focus on infection in dogs.

A tick must have been attached to a dog's body for at least 24 hours to infect the animal with the Borrelia burgdorferii bacterium, which causes Lyme disease. Through the bloodstream, the Borrelia burgdorferii bacterium travels through the body in search of a suitable place to settle; tissues, muscles, and organs are considered suitable locations.

Symptoms

Only 10% of all dogs infected with the Borrelia burgdorferii bacterium show symptoms. Because the symptoms are often vague and general, it can be difficult to determine whether a dog has Lyme disease. Symptoms associated with Lyme disease include:

• Recurring lameness due to inflamed joints
• Reduced appetite
• Fever
• Swollen glands around the tick bite
• Kidney damage
• Heart abnormalities
• Damage to the central nervous system
  
  

The characteristic red ring that appears around a tick bite in humans is rarely visible in dogs.

Diagnosis

Because the symptoms of Lyme disease are often very general, they may be attributed to another condition. As a result, the disease is often diagnosed only at a later stage, frequently when kidney failure occurs.

A veterinarian can diagnose a dog with Lyme disease based on the symptoms, the owner's observations, and a blood test. The blood test must determine whether the dog has produced antibodies against the Borrelia burgdorferii bacterium.

However, the blood test result may be false positive; this means that the bacterium is not currently present in the dog's body, but that the dog has produced antibodies against it (the dog was previously infected with the bacterium, but the body successfully eliminated it). To rule out a false-positive result, a veterinarian can perform an additional test, such as a PCR test. A PCR test can demonstrate whether DNA from the Borrelia burgdorferii bacterium is present in a dog's body tissues or fluids.

Treatment

A veterinarian will generally prescribe a course of antibiotics for an infected dog. This course lasts at least two to three weeks and, in some cases, even longer. In general, dogs respond well and quickly to a course of antibiotics. Because the joints often become inflamed with Lyme disease, a veterinarian may also prescribe anti-inflammatory medication; however, this is not a treatment but rather symptom relief.

Do you suspect that your dog has Lyme disease? Contact your veterinarian. The risk of lasting symptoms is lower when treatment is started early.

A dog may remain a carrier of the Borrelia burgdorferii bacterium. If a dog's immune system becomes weakened, for example due to illness or old age, the symptoms may reappear.