Vascular and Neuro-ophthalmic Pathology of Elaeophorosis in Elk

Abstract

Elaeophora schneideri was identified as the cause of a specific neuro-ophthalmic disorder of elk (Cerrus canadensis) in Arizona, Colorado. New Mexico, and Wyoming. This intra-arterial nematode was found within the cephalic arterial system in 10 of 16 elk with visual disturbances. Pathologic findings indicated that the parasite and the vascular lesions which it caused resulted in impairment of cephalic arterial circulation. Blindness and death were attributed to ischemic damage in the brain, eyes, and optic nerves. Although E. schneideri is a relatively common parasite of deer and domestic sheep in certain mountainous regions of the western and southwestern United States, it had not been reported in elk prior to this study.