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Pathogenes mission is to develop patent protected technologies for the diagnosis and treatment of parasitic diseases.

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Dr. Siobhan Ellison DVM, PHD, received a PhD in molecular biology in 2001 from the University of Florida where she had previously completed a Masters program in veterinary microbiology in 1976 and a Doctorate of Veterinary medicine in 1983.  Her PhD thesis was a study in molecular biology, cloning a novel gene from Sarcocystis neurona with a goal to developing tests that assist in diagnosing EPM. After she left UF, she developed the first successful EPM horse infection model, licensing the technology to Bayer Animal Health and later Schering Plough for testing EPM treatments.

Since 2001 she has continued to work and publish, the publications tell the story of EPM.

Pathogenes Publications tell the story of EPM

Who we are
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Equine protozoal myeloencephalitis (EPM) was recognized in horses in the 1950’s and Sarcocystis neurona was isolated from a horse in 1991. Our approach to making EPM a treatable disease is a correct diagnosis. 

The tools we use for diagnosis are antibody tests in serum.  These tests are based on our equine model of infection that we patented in 2001.  This technology led to understanding the early signs, understanding immune protection from vaccines, and ultimately the chronic inflammatory condition that leads to polyneuritis equi.

Sarcocystis fayeri is a  common infection in horses with a different life cycle and outcome.  Infection with S. fayeri is called Equine Muscular Sarcocystosis. We developed a test for the toxin present in disease causing strains.


Our tests use serum and are uniquely designed to distinguish between S. neurona, S. fayeri toxin, and poly- neuropathy.  The diseases caused by these three conditions are treated differently.  

Pathogenes collaborations with industry partners define treatment effects in EPM horses

Pathogenes model defined early signs of EPM

EPM vaccine shows efficacy in equine model

Polyneuropathy linked to Sarcocystis neurona infection in horses

About EPM
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Learn more about your case by using our highly specific tests.


You can understand more in a less technical format by reading the blogs about EPM, S. fayeri, pathogenesis of disease, and the role of polyneuritis.


You can follow our research by reading the peer reviewed literature.

Learn more

What is PNE?

Polyneuritis equi is a rare,  condition that  presents clinically with chronic  signs that often relapse. Affected horses have damaged peripheral nerves that can heal if the disease is recognized and treated appropriately. PNE is rare and  often overlooked as a diagnosis or confused with  EPM. These horses are called "sidewinders" due to the hemi-paresis and a sidewinding gait.

Clinical Trial PNE treatment

Our polyneuritis equi IND is designated under MUMS (minor use in a minor species) for the control of clinical signs that are associated with polyneuritis equi (PNE) in horses. Effectiveness is determined by conducting a field effectiveness trial and is the last step in bringing this much needed treatment to veterinarians for PNE horses. Blood testing and trial drugs are provided at no cost for the trial participants. This trial does not use a placebo.

What causes PNE

PNE is caused by chronic inflammation.  Inflammation  comes after infections that include protozoan parasites, viruses like herpes virus, gut parasites, or hind-gut ulcers. PNE can also be caused by some vaccinations. Chronic inflammation located on the peripheral nerves leads to the loss of myelin. (Myelin covers nerve fibers.) Neurodegeneration and auto-immune disease are end stage conditions.  There are  no current treatments, the prognosis is poor and most horses are euthanized.  We are working to bring the horse community the first licensed treatment for PNE. 

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15471 NW 112th Ave
Reddick, FL 32686

Cell: 352-214-5209
Fax: 352-591-4318


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