Shivering in a thoroughbred mare.

This research case documents a rare instance of a horse presenting with neuromuscular deficits resembling shivering in its left hind limb, with no detection of known pathogens or significant signs of muscle or nerve damage upon necropsy.

Case Presentation

• The study deals with an 11-year-old mare (female horse) who was suffering from neuromuscular deficits, which are signs of malfunctioning nerves and muscles, and resembled shivering in her left hind leg.

Necropsy Findings

• Upon performing the necropsy, a post-mortem examination essentially, there was no evidence of denervation atrophy (wasting of the muscles due to lack of nerve stimulus) in the gastrocnemius muscle (calf muscle) of the horse’s left hind limb.

Spinal Cord Investigation

• Despite there being no clear signs of muscle or nerve damage in the affected limb, the examination of the horse’s spinal cord revealed a small, right-sided lesion or harm in the region between the third and fourth, and fourth and fifth cervical vertebrae (C3-C4 and C4-C5). These areas of the spinal cord are located in the neck region of the vertebral column.

Pathogen Testing

• Despite the findings in the spinal cord, tests for common equine pathogens such as equine herpesvirus-1 and Sarcocystis spp. came back negative. Both of these pathogens are known to cause neurologic disorders in horses, but apparently were not present or responsible in this particular case.

Summary

• The study presents a unique case in veterinary neurology, where the typical causes for such disease symptoms – denervation atrophy in the muscle or presence of known neurologic pathogens – were not found. The condition of the mare remains unexplained, and further investigations to understand such cases can provide more insight into equine neurological disorders.