For auld lang syne, my dear,
for auld lang syne,
we'll take a cup of kindness yet,
for auld lang syne.
As another year closes, Pathogenes gives a big THANK YOU to those who contributed to our research studies. Each consult adds information to our system and renews our hope that we will find a cure for EPM. In 2017, we are concentrating on FDA-approved studies which move our treatments closer to full licensing as well as publications that explain our work. We fondly remember those animals along the way that brought us here, like Lily a paint mare that was one our first cases in 2013.
We two have run about the slopes,
and picked the daisies fine;
But we've wandered many a weary foot,
since auld lang syne.
An autoimmune test was (developed in 2014) and incorporated into our EPM panel in 2015. The S. fayeri assay was added in 2015. Results from these assays were published, hoping our information will make EPM a lot easier to understand. Our work taught us how to better prevent disease. The road to prevention starts with a correct diagnosis.
Importantly, horses with a diagnosis of EPM may suffer from S. neurona or S. fayeri sarcocystosis. Or they may have an autoimmune disease. Autoimmune disease is present when the horse’s immune system attacks myelin protein, the covering found on nerve tissues. Detecting antibodies against the horses own nervous tissues indicates the horse has polyneuritis. We suggest that autoimmune polyneuritis may start with a protozoal infection which stimulates chronic inflammation in some animals. Clinically, once the cause of the disease is identified, the horse can begin the recovery process. Antiprotozoal drugs aren’t the answer to autoimmune polyneuritis.
It is difficult to figure out what is going on in horses which “relapse” with supposed “EPM”. That is because horses can have one or a combination of three syndromes that we have identified as associated with S. neurona. The three syndromes are: S. neurona sarcocystosis, S. fayeri sarcocystosis, or autoimmune polyneuritis. Each of these diseases which looks like EPM has a different treatment protocol. Some “EPM” tests can’t distinguish S. neurona from S. fayeri. Our unique approach does just that.
The BIG question we wanted to answer was “Can we prevent EPM?” The answer is suggested in data from a complicated study that started a year ago. The study was non-blinded (everyone got the medication) and uncontrolled (no placebo was used). Treatment was given to horses with known relapsing/remitting EPM. To enter the study, the horses had to be successfully treated, they had a normal neurological gait score. It was important that there was a history of at least one EPM relapse that followed successful EPM treatment.
Horses were categorized as EPM (antibody against S. neurona), SF (S fayeri antitoxin present in the serum), or MPP (antibody against myelin protein or the against the neuritogenic peptide contained on the myelin protein). 2016 S fayeri Ellison 2015 MPP MP2 Assay
It was interesting to see that there were more S. fayeri-infected horses than S. neurona-infected horses. There were more autoimmune horses than expected; in fact the autoimmune group comprised the largest number of cases! The smallest group were horses in the EPM category, meaning there were antibodies against S. neurona present but not S. fayeri or antimyelin protein antibodies. It was obvious that horses with relapsing/remitting signs of EPM that have antimyelin protein antibodies needed an alternate diagnosis.
We interpreted a “treatment failure” as the horse getting signs consistent with EPM and the prophylaxis was not working. These horses were removed from the study and received an alternate treatment. Horses with a diagnosis of autoimmune polyneuritis received treatment according to protocols that have worked for the majority of cases. Horses with evidence of autoimmune polyneuritis failed in the first 3 months of treatment. Interestingly, the horses with a diagnosis of Sarcocystis infections did not fail.
We discovered some more interesting and surprising results. For example, we have evidence that horses with recurring EPM are re-exposed continually from the environment. We found that treating horses in the SF category eliminated the S. fayeri toxin that may be responsible for neuromuscular disease. And, it was possible to detect sub-clinical disease. Right now, we are working on a lab value to predict when sub-clinical disease turns into apparent disease.
We discussed this study with veterinarians at the 2016 AAEP meeting in Orlando, Florida, a gathering of veterinarians interested in EPM treatment and prophylaxis. Again, thank you to those who took the time to stop by and discuss your cases! The EPM prophylaxis paper is available , however we will share our view of the data and how it affects treatment decisions concerning your case now. Just give us a call. We need the consult form completed. Find it on our web site: www.pathogenes.com.
Overall, in 2016 we learned more about chronic disease, how to prevent EPM and the incidences of autoimmune polyneuritis. This year, we will add more information to the pathogenesis of disease and work out a method to stage polyneuritis in the diseased animal. We will continue to transfer our information to the EPM community and promote positive discussion among practitioners. And so we’ll take a cup o’ kindness yet, for auld lang syne.