Protozoan encephalomyelitis causing pelvic limb paresis in a yearling sheep

Authors: McGorum B, Woodman MP, Scott PR, Watt NJ, McDiarmid A
Publication: New Zealand Veterinary Journal, Volume 41, Issue 3, pp 139-141, Sep 1993
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Locomotor, Muscle/myology, Disease/defect, Nervous system/neurology, Parasites - internal, Protozoa, Infectious disease
Article class: Short Communication

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Abstract: A pelvic limb paresis of 6 weeks duration in a yearling sheep resulted from protozoan encephalomyelitis involving the spinal cord at the thoracolumbar junction. An elevated lumbosacral cerebrospinal fluid protein concentration but normal cisternal cerebrospinal fluid protein concentration indicated the presence of a thoracolumbar inflammatory lesion resulting in cord compression which obstructed the rostral flow of the cerebrospinal fluid. Under general anaesthesia, myelography at the lumbo-sacral site demonstrated blockage to the rostral flow of contrast medium at T₁₃/L₁. At necropsy, there were no gross pathological changes at T₁₃/L₁, but histopathology revealed non-tract specific lymphocytic perivascular cuffing, axonal swelling and oedema in the spinal cord, characteristic of a protozoal encephalomyelitis. No parasites were detected in the multiple spinal cord sections examined but immunocytochemistry identified antigens cross-reactive with Sarcocystis spp. antigens in glial cells in these lesions.

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