A Neuropathy in Goats Caused by Experimental Coyotillo (Karwinskia humboldtiana) Poisoning

Abstract

Seven goats were poisoned with daily oral doses of coyotillo fruits and killed at various times after day 12. The distribution of lesions was studied in a sensory nerve, in short and long motor nerves, and at proximal and distal sites of a long motor nerve. Fibers with Schwann-cell lesions (swollen Schwann cells or segmental demyelination) were widespread and outnumbered fibers with Wallerian degeneration in most sites. The percentage of fibers that were undergoing Wallerian degeneration was much greater in long motor nerves than in short ones and was much greater at a distal site of a long motor nerve than at a proximal site. The results were compatible with axonal injury being secondary to Schwann-cell injury and cumulative throughout the lengths of affected fibers, resulting in distal axonal degeneration.