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The Positive Blue Dot of Lyme Disease

6/29/2015

What does it mean when the dot for Lyme disease turns blue on the heartworm 4DX test? Does your dog really have Lyme? How can you tell? What should you do?

The dot is supposed to turn blue when antibodies against Lyme disease are present in the blood sample. Additionally, the blueness of the dot is supposed to correspond to the number of antibodies. This is why a pale blue dot is recorded as a “faint positive” for Lyme, and a dark blue dot is a “strong positive.”

This test is not 100% reliable, and I would never diagnose a dog with Lyme disease based on it. At this point you have several options:

Treat for Lyme disease. A 30-day course of antibiotics is often presented as a reasonable course of action. However, antibiotics are dangerous drugs with significant side effects, and antibiotic overuse is what has led to MRSA and other resistant strains of bacteria. Since dogs commonly test positive year after year, is it good medicine to treat your patient with antibiotics for a month every year? It sounds ridiculous, but I read medical records every day that tell that story. What is being treated in these cases? The dog owner’s and the vet’s anxiety.
Do further testing. Sometimes a C6 titer supports a diagnosis of Lyme disease, and sometimes completely negates it in spite of the blue dot.
Do nothing. The presence of antibodies indicates exposure. That means that the dog has been bitten by a tick in the past that was carrying the Lyme bacteria. Does the dog actually have an active case of Lyme disease? This needs to be determined by the physical exam and pet owner interview. If your dog has active Lyme disease, there must be symptoms to support that diagnosis.

What if you are afraid of Lyme disease, the dot is blue, and you don’t want to use antibiotics? Options abound!

Give herbs that strengthen the immune system. Echinacea is the most common one that comes to mind here. Use a tablet, capsule, or an alcohol-free tincture. Dogs are dosed as a percentage of the human dose. For example, a 50 lb. dog gets approximately 50% of the recommended human dose. Other useful herbs are Cat’s Claw and Goldenseal.
Support the immune system in other ways. Is your dog on raw food? Now is a good time to start! Do you give probiotic and digestive enzyme supplements? Remind yourself to put them in your dog’s food daily. Are you giving your dog high antioxidant supplements, like spirulina and bee pollen? Why not?
Give homeopathic Ledum 1M, 1 pellet by mouth three times a day for three days.

Better yet, focus on building a strong immune system before the dot has a chance to turn blue.

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Making Sense of Antibody Titers

6/22/2015

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Antibody titers are available for the major infectious diseases of dogs and cats, including distemper, parvovirus, panleukopenia, calicivirus, herpesvirus, and rabies. The purpose of running an antibody titer is to verify that the animal has an objective measure of immunity to the disease in question. The titer itself is a blood test, so your vet will draw a blood sample from your pet and send it to a laboratory. The lab determines the greatest dilution at which antibodies to the disease in question can still be found. The laboratory also determines a dilution below which (they suggest) your pet will not have enough antibodies should it encounter the disease.

Now, titer results bear interpretation. It is not realistic to say that if there aren’t enough antibodies, or any measurable antibodies, then there is no immunity. Immunity to disease doesn’t work that way. This is why a titer test should not be used as a screening tool to determine whether your pet needs to be revaccinated.

For example, I have been vaccinated against polio three times in my life, the last time being 27 years ago. Do I have antibodies to polio in my blood right now? I hope not! What a waste of resources for my body to be busy making antibodies against a disease I will likely never encounter. Could I make antibodies to polio if I needed to? Sure, in a fraction of a second. This is why we have whole parts of the immune system devoted to remembering pathogens that we have met previously.

When I do titer tests on dogs for distemper and parvovirus, a very common result is that the dog has a low titer for distemper and a high titer for parvo. Sometimes there is no measurable distemper titer, but almost always that high parvo titer shows up. Why is that?

Parvo is a very stable virus that lasts practically forever in the environment. It is present wherever dogs have been. When dogs are vaccinated against parvo, they shed the virus in their feces for approximately 3 weeks afterwards. Therefore the virus is constantly being renewed in the environment as well. If you take your dog to a public park, parvovirus is there. If the people who lived in your house before you had a dog, parvovirus is there. This means that there is constant exposure and re-exposure to the virus.

Distemper, on the other hand, doesn’t last long outside the dog. Dogs need close contact to transmit distemper. They need to cough on each other and breathe in each other’s faces. Distemper is no longer a common disease outside of the vaccine, so there isn’t the routine exposure like dogs have with parvovirus. I have seen and treated many cases of parvo in my 18-year career as a veterinarian, but only one case of distemper (and that was vaccine-induced).

All this means that your dog might have a low or even not a measurable titer to distemper. Then how do you know whether they are immune? It’s difficult to know. There is also a possibility that the dog did not respond to the vaccine as desired and did not produce antibodies. Will giving another vaccine booster force the dog’s immune system to produce antibodies? Nobody knows.

So this is the challenge with vaccine titer testing. We love it when test results are clear cut, and yes means yes and no means no. Unfortunately that is not the case with titers.

When I interpret these results, I think that any measurable antibody is a positive result, even if it doesn’t meet the laboratory standard for a “protective titer.” If you can produce one antibody, you can likely produce trillions (or however many it would take to fight off a disease) in nanoseconds. If you have no measurable titer, then the answer is unknown.

As far as I can tell, one antibody titer should be sufficient for the animal’s lifetime. Once you have proven your body’s ability to produce antibodies, you will always be able to. Even quite unhealthy animals and people will respond to vaccination with a positive titer, and this tells me that antibody production is quite easy for the body to do. Therefore, as long as you maintain a basic semblance of health and your immune system doesn’t self-destruct, you should be able to produce antibodies.

Please note that I am discussing viral diseases here, and that this information has no bearing on bacterial diseases, which are a whole other can of worms.

I was vaccinated for rabies in vet school, so likely about 20 years ago. Three or four years later I had my rabies titer checked, and it was high. Nobody ever sends me a postcard telling me to booster my vaccine, and I don’t ever need to check my titer again. It is good for life. And these vaccines likely provide our pets with lifelong immunity as well. For more information, check out the work done by Dr. Ron Schultz and Dr. Jean Dodds, and the Rabies Challenge Fund.

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The Positive Blue Dot of Lyme Disease

Making Sense of Antibody Titers

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