Lyme disease is a multi-system disorder caused by the spirochete bacteria Borrelia burgdorferi and transmitted by ticks. It is the most commonly reported tick-borne disease in the U.S. human population, according to the Center for Disease Control (CDC). And, in a 2001 survey, Lyme-positve dogs were found in all 48 of the contiguous Unites States.
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.
What are the clinical signs?
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, symptoms of
Lyme disease are more difficult to detect in animals than in people.
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.
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 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 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 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
Cedar trees. Here they wait until their sensors detect a close-by 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.
How do I remove a tick from
my dog?
Check your pet immediately after it has been in a tick-infected area. The Deer
Tick is a small tick and only about pinhead size in juvenile stage, but a little
more obvious in 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 finger nails 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.
Is there a vaccine that
will protect my dog from Lyme disease?
A vaccine is now available for protecting dogs against Lyme disease. This vaccine
is initially given twice, at two- to three-week intervals. Annual revaccination
is also necessary to maintain immunity. The vaccine has been shown to be safe
and effective. Some pets will receive the vaccine every two to three years based
on the vaccine used, your pet’s lifestyle and individual risk assessment.
Be sure to discuss any questions you may have regarding the type and frequency
of vaccination with your veterinarian.