Retinal degeneration in a 2.5 year old fennec fox

Abstract

A 2.5-year-old male castrated fennec fox (Vulpes zerda) presented to Cornell’s Ophthalmology Service with a chief complaint of running into objects at home. According to the owner, the suspected vision deficit had started approximately seven months ago, but had become progressively worse in the past month. Ophthalmic examination revealed bilateral retinal degeneration, characterized by avascular retinas, atrophy of the optic nerves, and increased reflectivity of the tapetal fundus. Primary differential diagnoses included progressive retinal atrophy (PRA) and taurine deficiency retinopathy. A blood sample was submitted to OptiGen (Ithaca, NY) to genetically screen for known mutations causing PRA in domestic dogs. The fox was negative for the progressive rod cone degeneration (PRCD) mutation. An echocardiogram was performed to rule out dilated cardiomyopathy (DCM), a known sequela of taurine deficiency in foxes. No evidence of DCM was present. Prognosis was grave for return of vision and very good for quality of life. Like dogs and cats, the fox acclimated well to blindness at home.