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New serum test for Sidewinders

Diagnosing an autoimmune reaction in a sidewinding horse can lead to effective treatment!  Pathogenes Testing Options

Sidewinder is a term that describes the clinical presentation of a horse with a unilateral weakness/hemiparesis causing the hind quarter to track either side of the front quarter. Cauda equina neuritis (CEN) is an uncommon condition in the horse clinically characterized by paresis/paralysis of the tail, rectum, and bladder and a loss of sensation in the sacral dermatome with a surrounding zone of hyperesthesia and can be seen in sidewinding horses. Frequently, CEN is associated with cranial nerve paralysis, hindquarter muscle wasting, and an abnormal gait.

The disease in sidewinders describes a syndrome with characteristic clinical signs, predictable outcomes, and no recognized necropsy findings.  It is termed idiopathic. Often clinical signs are due to peripheral and central nervous system (CNS) inflammation, central lesions may indicate the presence of encephalomyelitis. The inflammatory pathological lesions of CEN is similar to those described in allergic neuritis. Experimental allergic encephalitis (EAE) is an induced autoimmune disease of the CNS that is readily induced in many mammalian species by immunization with CNS tissues.

Horses with serum antibody to specific proteins correlate well with clinical and pathologically diagnosed disease and indicate the pathogenesis of disease is immune mediated. The purpose of our current investigation is to determine the presence of antibodies against specific proteins in serum of horses with a diagnosis of idiopathic encephalomyelitis that present with a sidewinding gait. Give us a call to see if your case qualifies for free testing.  We may have your sample on file if it was submitted within the last 6 months, if we tested your horse for S. neurona antibody, that was clinically a sidewinder, we will go back and run our new test on the saved serum.

Several things are important to us.  The degree of disease based on the modified Rostami scale (a number between 0 and 3).  The score is 0 = a normal animal; 1 = is mild (more than 5% weight loss and a flaccid tail; 2 = moderate; and 3= severe with paraplegia or tetraplegia; a typical sidewinding gait.  The distinction between a central and peripheral lesion that is causing the signs is an important factor in diagnosis and treatment expectations.  While there can be both central and peripheral lesions, we want to discriminate between the two populations of horses if a distinction exists.

Email us the answer to the following questions (give a numerical score for the first assessment; circle the presence of any other signs) :

  • Clinical assessment (numerical score)
  • Ataxic, gait anomaly, sidewinder
  • Weight loss
  • Signs attributable to central lesion
  • Behavior change
  • Muscle wasting: back muscles
  • Muscle wasting: gluteal
  • Muscle wasting: masseter muscles
  • Tail paresis
  • Urinary incontinence
  • Rectal dysfunction
  • Perianal analgesia
  • Cranial nerve neuropathy
  • Muzzle twist
  • Eye lid paresis
  • Facial paresis

Update: 2018 ELISA Submission Form

Determining the cause of polyneuritis equi and autoimmune polyneuritis may be possible.  There are no published protocols for polyneuritis equi, our treatment protocol is available to veterinarians when they are faced with a horse with antibodies against myelin protein.  Our next step is in staging disease.  Our autoimmune tests, MPP/MP2 can help us do that.  Call for details.


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