The increased prevalence of ticks in the Chittenden County over the last 10 years has led to a greater number of dogs “testing positive” for Lyme disease.
The first thing to know when your dog tests positive for Lyme disease is that this test merely identifies dogs that have been exposed to the organism that can cause Lyme disease, not the illness itself. Some time since, or just prior to, the last test, your dog was bitten by a tick that harbored the Lyme bacteria, Borrelia burgdorferi. According to a study at Cornell University, 94% of dogs that have been exposed will never develop disease symptoms. This means a positive test is not the end of the world.
Clinical Lyme disease manifests itself in a variety of ways but most commonly we will see limping that is often combined with a decreased appetite and energy level. A physical exam will typically identify joint swelling, pain, fever and sometimes enlarged lymph nodes. If your dog is exhibiting these clinical signs then treatment is imperative. The antibiotic Doxycycline is our first choice. Signs typically resolve within the first three days and improvement can be seen within 24 hours. Typically a 3-4 week course of antibiotics is recommended but longer treatments are sometimes advised.
What lameness can look like with Lyme disease (not a great video but a good example of what to look for):
At River Cove Animal Hospital we do not recommend treatment if your dog merely tests positive and is not sick. We stand very little to gain with a prolonged course of antibiotics as treatment is typically not successful in eradicating the organism from the body. Though treatment is very successful in eliminating clinical signs in those that are sick it cannot eliminate the infection completely, as the organism is very good at hiding. Thus dogs testing positive will remain positive for years if not forever. Some veterinarians advocate treatment in all cases, even those that test positive but are asymptomatic, in hopes of preventing illness prior to the onset of signs. Since only 5 % of exposed animals get sick, we feel it is unnecessary and the side effects of over using antibiotics are greater than the risk of disease itself.
The test identifies a specific antibody that is produced by the body only after natural exposure from the bite of a deer tick. It is very sensitive, so false positives are unlikely. The test used at River Cove Animal Hospital is the 4DX test. It not only looks for Lyme Disease but also rules out Heartworm, Anaplasmosis, and Ehrlichia. The later two are additional tick born illness that are often found as confections with Lyme disease. A positive test is seen as a color change much like a pregnancy test. Some practitioners interpret the degree of color change to infer the “severity” of infection. A quantitative test is available that gives us a numeric level or titer. However, we rarely feel the expense of this test is warranted as results will probably have no impact on our decision to treat. The test may have value in monitoring response to treatment but we at River Cove generally do not recommend further testing. Please ask your veterinarian if this test is right for your dog.
Once your pet is Lyme positive it is important to monitor for clinical signs such as lameness, swollen joints, fever, lethargy and decreased appetite. If these signs are noted it is possible that Lyme is the culprit; however, other causes can often be identified. Remember around 95% of dogs that are positive will never get sick.
Even if your dog has been exposed to Lyme disease, you and your family are not at risk of catching the disease from your dog. You are at risk of Lyme disease because you venture into the same outdoor environment as your dog and encounter ticks not because your dog is positive.
Though most dogs that get Lyme disease will develop arthritis, there is another form of disease that is important to note. The Lyme organism and antibodies produced after exposure can damage the filter in the kidneys. This is the silent killer of Lyme disease. If your pet becomes painful it is obvious and treatment can be implemented early. The effect on the kidney’s can go unnoticed until it is too late. If we can identify this rare form of Lyme disease early we stand a better chance of controlling or curing it. At River Cove Animal Hospital we recommend evaluating a urine sample for small amounts of protein in all dogs that test positive for Lyme disease to determine if the kidneys have been affected. If found, treatment and monitoring can often be started before serious renal issues arise. At this time we recommend testing the urine annually in individuals that recurrently test positive.
It is controversial whether to vaccinate dogs for Lyme disease that have already been exposed. Some specialists feel vaccination will help prevent individuals from developing disease. While others are concerned that the vaccine may in fact increase the risk of kidney damage in those that have already had natural exposure. At this time we generally do not advocate vaccinating individuals that have already been exposed but please do not hesitate to talk with your veterinarian about what is best for your dog.
Points to Remember When Your Dog Tests Positive for Lyme Disease:
1) A Lyme positive test identifies exposure not illness; 95% never get sick.
2) Treatment is only indicated in individuals exhibiting clinical signs.
3) Monitor for limping, swollen joints, lethargy and decreased appetite and contact us at River Cove Animal Hospital if any of these signs arise.
4) Evaluating a urine sample for protein on an annual basis is important to rule out underlying kidney damage before signs arise.
5) Your dog does not pose a risk to you or your family.
6) Continued tick prevention to limit further exposure is very important. Daily tick checks, prompt tick removal and using and staying current with the best tick preventatives are the mainstays of preventing Lyme disease in your dog.
* Please review your tick medication. All tick preventatives are not equal. There is a huge variation in efficacy. Please contact us at River Cove Animal Hospital for the best method to prevent ticks and therefore ultimately prevent Lyme disease in your dog.