If your dog tests positive for Lyme disease in your veterinarian’s office, it should be a no-brainer that he should be treated, right? Well, unfortunately, that’s not always the case. If you live in an area that sees Lyme disease, your veterinarian probably has an in-clinic test for Lyme that is combined with a heartworm test. Many veterinarians run this test, called the 3dx test, every year as a way to screen for heartworm disease.

If your dog tests positive in the 3dx test, he has definitely been infected with the organism that causes Lyme disease.

But here’s the catch: The results of that test can remain positive for a year or more after actual infection. So, when do we treat for Lyme disease? A pet that tests positive for Lyme could have actually been infected months and months ago and not need treatment because his immune system did its job and cleared the initial infection on its own. The organism that causes Lyme disease is great at avoiding the immune system and will go on to hide in the dog’s body, and treatment with antibiotics will not affect these latent infections.

Antibiotic treatment 

Antibiotics are the mainstay of treatment for Lyme, and I always treat dogs who present with clinical signs of Lyme disease (lameness, fever, enlarged lymph nodes, etc.), but when it comes to symptom-free dogs who test positive for Lyme, it’s just not black and white. That’s why your vet may have a discussion with you about further testing.

There is another blood test that your veterinarian can order to help determine whether your dog needs antibiotic therapy. It also can serve as a way to monitor the effectiveness of therapy, because if the results don’t change, your vet may consider another round of antibiotics. This test can also come in handy in the long run because the chances that your dog tests positive for Lyme the year after an initial positive test are quite high. Your vet will want to know if the test is still positive from the previous year or if your dog has been re-infected.

In a previous blog, I mentioned that Lyme disease may be responsible for kidney disease in some pets, so your vet may also suggest that you drop off a sample of your dog’s urine to run tests on as well.

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With all of the confusion surrounding treatment, it’s best to try and avoid the situation altogether. As with all conditions, prevention is key. We know that once a tick attaches to your dog, it takes at least 48 hours to transmit Lyme disease. This means that by performing daily tick checks (and removing attached ticks), you can avoid the transmission of Lyme disease to your pet. Because no one I know can commit to doing tick checks 365 days a year (and because it is easy to miss small ticks in long-haired breeds), tick control is imperative. There are several options to consider, including monthly topical or internal treatments and vaccination.

Your veterinarian may offer a Lyme vaccine for your dog if you live in an endemic area. Lyme vaccines are another sticky wicket in the veterinary community, as there are debates as to when they should be given and whether they should be given to dogs who already have tested positive.

Like I said, there are many different opinions regarding the treatment and prevention of Lyme disease, and if you ask several different veterinarians their opinions, you will likely get several different answers. Work with your veterinarian to find a plan that is best for your family.

Jun 12, 2012
Pet Health

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