Saturday, July 24, 2010

Lyme Disease

What is Lyme Disease?




Lyme Disease is caused by a spirochete, Borrelia burgdorferi. A spirochete is a type of bacterium. It is transmitted to dogs through the bite of a tick. Once in the blood stream, the Lyme disease organism is carried to many parts of the body and is likely to localize in joints. It was first thought that only a few types of ticks could transmit this disease, but now it appears that several common species may be involved. The most common type of tick to carry Lyme disease is the Deer tick.

Can Lyme disease also affect people?


Yes, but people do not get it directly from dogs. They get it from being bitten by the same ticks that transmit it to dogs. Therefore, preventing exposure to ticks is important for you and your dog.


Many pet owners are unaware of how many ticks your outdoor cat can bring into your home. using preventive medications on your cats is just as important as protecting your dog.


What are the clinical signs?


Many people will develop a characteristic "bull's eye" rash at the site of the bite within three to thirty days. The characteristic rash does not develop in dogs or cats. Because the other 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.


80-90% of dogs positive for exposure show no clinical signs of Lyme disease when routinely screened at their annual health exam.


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 egg shells." 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 are 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 is any 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 also occur in animals with suppressed immune systems.


The Second test is a polymerase chain reaction (PCR) test, a DNA test that is very specific and sensitive. However, not all 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, and sandy areas. They find their way onto an animal by climbing to the top of a leaf blade of grass, or short trees, especially Ceder trees. Using a topical preventive or tick collar is highly reccommended. Talk to your veterinarian to determine which product would best suite your pet.