Lyme disease is caused by a spirochete, Borrelia burgdorferi. A spirochete is a type of bacterium. It is transmitted to dogs (and, uncommonly, cats) through the bite of a tick. Once in the blood stream, the Lyme disease organism is carried to many parts of the body, often localizing in joints. Although several species of tick are capable of carrying lyme disease, the most common carrier is the Deer Tick.
Can Lyme disease also affect people?
Yes, people, like dogs, can contract lyme disease by being bitten by affected ticks. Dogs can not directly transmit the disease to people. However, infected dogs can serve as a reservoir for lyme disease in our environment, thereby increasing the risk to people. Therefore, preventing exposure to ticks is important for both you and your dog.
What are the clinical signs of Lyme disease?
Many people with Lyme disease develop a characteristic “bull’s-eye” rash at the site of the bite within three to thirty days. For these people, the disease can be easily diagnosed at an early stage. However, in animals symptoms of Lyme disease are more difficult to detect.
The characteristic rash seen in people does not develop in dogs or cats. Because symptoms of the disease may be delayed or go unrecognized, and because the symptoms are similar to those of many other diseases, Lyme disease in animals is often not considered until other diseases have been eliminated.
Many dogs affected with Lyme disease are taken to a veterinarian because they seem to be experiencing generalized pain and have stopped eating. Affected dogs have been described as if they were “walking on eggshells.” Often these pets have high fevers. Dogs may also begin limping. This painful lameness often appears suddenly and may shift from one leg to another. If untreated, it may eventually disappear, only to recur weeks or months later.
Some pets are affected with the Lyme disease organism for over a year before they finally show symptoms. By this time, the disease may be widespread throughout the body.
How is Lyme disease diagnosed?
Dogs with lameness, swollen joints, and fever should be suspected of having Lyme disease. However, other diseases may also cause these symptoms. There are two blood tests that may be used for confirmation. The first (and more common initial test) is an antibody test. This test does not detect the actual spirochete in the blood but does detect the presence of antibodies created by exposure to the organism. A test can be falsely negative if the dog is infected but has not yet formed antibodies or if it never forms enough antibodies to cause a positive reaction. This may occur in animals with suppressed immune systems. Some dogs that have been infected for long periods of time may no longer have enough antibodies present to be detected by the test. Therefore, a positive test is meaningful, but a negative is not.
The second test is the polymerase chain reaction (PCR) test, a DNA test that is very specific and sensitive. However, not all infected dogs have the spirochete in their blood cells. If a blood sample is tested, a false negative may occur. The best sample for PCR testing is the fluid from an affected joint.
How is Lyme disease treated?
Because the Lyme spirochete is a bacterium, it can be controlled by antibiotics. However, a lengthy course of treatment is necessary to completely eradicate the organism. The initial antibiotic selected to treat an infected pet may not be effective against the disease, especially if the infection is long-standing. In this situation, changing to another antibiotic is often effective. Occasionally, the initial infection will recur, or the pet will become re-infected after being bitten by another infected tick.
How can I prevent my dog from getting Lyme disease?
The key to prevention is keeping your dog from being exposed to ticks. Ticks are found in grassy, wooded, or sandy areas. They find their way onto an animal by climbing to the top of a leaf, blade of grass, or short trees. Here they wait until their sensors detect a nearby animal on which to crawl or drop. Keeping animals from thick underbrush reduces their exposure to ticks. Dogs should be kept on trails when walked near wooded or tall grass areas. Using products such as Frontline Plus to kill ticks will also help prevent transmission of Lyme disease to your dog.
Is there a vaccine that will protect my dog from Lyme disease?
A vaccine is now available to help protect dogs against Lyme disease. This vaccine is initially given twice (three to four weeks apart) and is then boostered annually to maintain immunity. The vaccine has been shown to be safe and effective.
How do I remove a tick from my dog?
Check your pet immediately after it has been in a tick-infested area. The Deer Tick is a small tick and only about pinhead size in its juvenile stage, but is a little more obvious in its adult phase and after feeding. If you find a tick moving on your pet, the tick has not fed. Remove the tick promptly and place it in rubbing alcohol or crush it between two solid surfaces. If you find a tick attached to your pet, grasp the tick with fine tweezers or your fingernails near the dog’s skin and firmly pull it straight out. You may need another person to help restrain your dog. Removing the tick quickly is important since the disease is not transmitted until the tick has fed for approximately twelve hours. If you crush the tick, do not get the tick’s contents, including blood, on your skin. The spirochete that causes Lyme disease can pass through a wound or cut in your skin.