Products & Articles

Lyme, Anaplasmosis, EPM in the Horse: Relapses, Thoughts and Theories

The opposite of health is disease and in the horse, we have many chronic and likewise frustrating health conditions.  Many include lameness as a result of direct joint or soft tissue damage, which continue to inflict pain and lameness on the patient as a normal course of the condition.  In other cases, we deal with the increasing incidence of Lyme disease, Anaplasmosis, and EPM, which in and of themselves can be frustrating due to the often high recurrence rate in certain patient groups.  Given this group of chronic diseases, which often come with hefty ongoing medical costs and variable outcomes, we need to step back and really evaluate the conditions and how the patient is responding, if we are to come up with better solutions.

TIcks EPM, Lyme, and Anaplasmosis in Horse
Ticks EPM, Lyme, and Anaplasmosis in Horse

Vector borne diseases are those which are transmitted amongst humans and animals usually by insects.  Lyme disease, Anaplasmosis, and EPM generally fall into this group, although EPM is believed to involved transmission via other mammals such as the Opossum. Vectors include ticks, fleas, and biting flies or other insects such as mosquitos.  Given the route of transmission, there are times of the year in which there are higher occurence rates such as in spring and summer, when the insects are more prevalent.  The northeastern section of the United States appears to be a hot-spot for certain vector borne conditions, including Lyme and Anaplasmosis, which seem to be increasing in prevalence here and in other areas with each new year.

One of the biggest health concerns amongst horse owners that I consult with is usually one of these three conditions; EPM, Lyme, and Anaplasmosis. Often, the conditions are mentioned as part of the horse’s medical history, but no longer appear to be a problem directly, while in others, the major complaint is an evident recurrence or relapse of the condition, despite proper medical therapy.  The ongoing chronicity of these conditions can be frustrating to both owner and veterinarian, not to mention result in lost performance and potential income.  When the patients relapse or reocurr, we often reinitiate the same prior therapies, hoping for different results.  In the case of EPM, there is talk of using lower doses of antiprotozoal medications on a daily and ongoing basis in chronic relapsers or in areas of high prevalence of the disease.  Is this really the way to go??

Over the past 8 years, we have had the privilege of working with several horse owners experiencing a relapse of one of these three conditions, being non-responsive to medical therapies.  I have always held the philosophy that a compromised or improper immune response is a major contributing factor not only to the development of these diseases, but also likewise played a role in the ongoing presence of the condition and failure to respond to therapies. In reality, these conditions are ‘treated’ with antibiotics or anti-protozoal medications, not with the goal of ‘curing’ the disease, but more so with the goal to reduce the numbers of organisms (bacteria or protozoal) to a more acceptable level in the hope that the body’s immune response would kick in and clear the rest…essentially restoring health.  So, if we are dependent on the immune system to restore health and kick in, then this implies that quite possibly, it was deficient or not working properly to begin with.

In many cases of Lyme and Anaplasmosis, of which many were recurrent or relapsers, the patients would often respond very favorably through the use of herbs to control the inflammatory response and balance the immune system.  Actually, many of these patients that responded had failed to respond to continued courses of medications over the course of months or years.  A high percentage of these patients actually did so well that their original titers returned to a normal state within 90 days and they returned to active competition.

In our EPM cases, even before the development of our Cur-OST® formulas, we would use traditional medications but always support the patient with immune enhancing agents including Levamisole or later, mushroom polysaccharides.  When we did this, the patient outcomes were much better and the relapse rate was much lower.  Many of these patients also had evidence of a deficient immune response at the start of therapy, as noted by a reduced lymphocyte count on blood work.  Could this have been the door that was left open, which allowed the invasion of the parasite?

Looking Deeper into EPM, Lyme, and Anaplasmosis in the Horse

I just returned from a veterinary convention this past weekend, in which many topics were discussed and reviewed.  It does not occur often, but one lecture at the end of the weekend left me thinking and I mean really thinking.  It was a discussion on emerging diseases in the horse with a focus on an organism called Bartonella, which is a bacteria.  The speaker was a well known researcher in his field from a well known university, but his focus was not so much on the horse, but more so making implications as to what could potentially be.

Bartonella is a vector transmitted bacterial infection, impacting humans, pets and yes…horses.  The exact life cycle and mode of transmission of this bacteria is not known, but is being studied, however it has been around since at least the early 1990’s, being cited in medical research.  In veterinary practice, we experienced it with cats and managed it to the best of our abilities, but in people and horses, the infection is not completely understood due to lack of exposure to the subject matter.

What was relayed during this lecture was what was known about Bartonella and implications.  The long and the short of it is that in many cases of disease, including joints, neurological and other conditions, Bartonella is known to be a player.  Not all of the time, but a higher percentage than what we originally thought.  The reason for this is that in the past, our ability to detect this organism has been poor.  It is hard to culture and methods to detect were primitive as compared to EPM, Lyme or Anaplasmosis.  In more recent times, on the research side, they are developing more precise means of detecting Bartonella and with this, are discovering how it appears to be more involved than what we originally thought.  They are finding it in many cases of cardiovascular, neurological and even mental conditions in people.  In animals, it appears to be causing similar clinical problems, often those found in cases of Anaplasmosis, EPM and even Lyme disease.  It is being found in inflammed joints, infections, in the spinal fluid and other areas of the body.  As in the case of EPM, Lyme and Anaplasmosis; Bartonella elicits an inflammatory response and with this, clinical pain and cellular deterioration occur.  It was even noted that in some cases of canine lymphoma (cancer), Bartonella was found within the lymph nodes and a course of appropriate antibiotics actually cured the cancer due to involvement of the organism.  Bartonella was even noted to be potentially involved in cases of laminitis and navicular disease, due to the organism’s impact on the circulatory system.

The interesting thing to me is several fold.  First, in many human patients, they were likewise not only positive for Bartonella but also positive for Lyme and even Anaplasmosis.  When antibiotics such as Doxycycline were used for therapy, even for 6 months time, the Lyme and Anaplasma titers dropped but the Bartonella levels did not.  As the speaker mentioned, he didn’t think you could ‘float a person or animal in enough Doxycycline to kill the organism’, which implies that Doxycycline and other tetracycline antibiotics are likely not very effective.  No other therapy options have been recommended to the best of my knowledge and there is still much to learn and discover about this organism.

In horses, transmission was not really known.  Of course, it could be a vector such as fly or tick, but the speaker mentioned that the barn cat was a major carrier of the Bartonella organism and that somehow, due to potential exposure to the barn cat, the horse was becoming infected…but how?  Again, we don’t know and there is much to learn.

Further Thoughts and Considerations

Taking all of this into consideration, I have to think back on the multitude of equine patients that I have consulted with over the years.  Most of these patients had a history of Lyme, Anaplasmosis or EPM and either responded to traditional therapy and never looked back or they responded then relapsed or just failed to respond all together.  When modifications were made to diet and herbal therapies initiated to ‘rebalance’ the inflammatory and immune response, the patients responded favorably.

Is it possible that yes, indeed, we have an underlying immune deficiency which is opening the door for these infections to take place?  Could diet, stressors and other factors be impacting overall health so negatively, beyond our level of acceptance, that the incident rate of these conditions is increasing and response to therapy is decreasing?

Could we not only have an EPM, Lyme or Anaplasma infection BUT also have a concurrent Bartonella infection?  Could many of our laminitis and navicular cases actually be linked to Bartonella and poor immune function? This may explain partially why so many of these patients ‘relapse’ on one level or another.  Could it be that we really eliminated the Lyme or Anaplasma organism, but yet Bartonella is still present and causing clinical problems?

I think that the answer is really that both of these theories are correct, but are hard to prove.  We know, based on clinical evidence and response to dietary and herbal therapy, that likely at least the first theory is correct, however proving that Bartonella is present proves more difficult. A high percentage of these patients are responding, but is this due purely to restored or enhanced immune function, which then allows the host to eliminate the invaders? We do not know, to be honest.  In some cases, the patients respond fully but in others, they required ongoing and daily immune support in order to maintain their health, which implies some sort of inherent deficiency.

As the speaker mentioned, we do not know the mode of transmission to the equine patient, but we do know that cats harbor the bacteria and that fleas do as well.  When connecting the two, we know that fleas leave ‘dirt’ or fecal material behind, which is known to carry the Bartonella organisms.  If this is true, is it possible that the feces from the cat does as well?  Could the mode of transmission also include an oral route, meaning the horses actually consume the organism?

If this were true, we would expect the body’s natural defenses such as stomach acid and immune response to take over and be protective…HOWEVER, in today’s equine world these two mechanisms cannot be relied upon.  We have an over use of stomach acid reducing medications being used, which lower stomach acid production and thus, is less likely to be protective. Second, we have a high incidence of stomach and hindgut ulcers, which is essentially an opening for the bacteria to penetrate.  We also have a high incidence of leaky gut syndrome and altered normal bacterial populations in the horse, much like that seen in human studies, which further weakens host defenses including the immune response.

So…could the Bartonella organism infect the horse as a matter of course, due to altered overall health and immune response?  This is a theory we have worked on for some time now, not necessarily looking at Bartonella, but more so looking at impact of leaky gut syndrome and altered bacterial flora in the gut of the horse and how this potentially contributes to allergies, poor immune function and even lameness conditions including laminitis and navicular.

In the end, this article is not meant to alarm or create concern, as this organism is not really new, but more so just new in regards to being found.  I think it has been a part of our disease processes, in humans and animals, for quite some time, but we are just now starting to recognize it.  In regards to therapies, we always look to the pharmaceutical world in these cases, seeking a new antibiotic in these cases…which maybe someday it will come.  More so, I think we need to see it for what it is, potentially, and that is an indicator for poor overall health and immune function.  These two factors play a major role in almost any disease, human or animal, but maybe now is the time to accept and make changes to our regimens and approaches.


Thank you.

Tom Schell, D.V.M.

Nouvelle Research, Inc.

Leave a Comment

Your email address will not be published. Required fields are marked *