Equine infectious ulcerative keratitis uveitis (Proceedings)


Equine infectious ulcerative keratitis uveitis (Proceedings)

Aug 01, 2011


     o Moon Blindness, Periodic Ophthalmia
     o Most common cause of blindness in horses
          • 2-5% of US horses
     o Recurrent episodes of intraocular inflammation separated by quiescence
     o What causes ERU?
          • Genetic
          • Environment
          • Cause of initial uveitis
     o Etiology debatable, but agreement that a dysregulated ocular immune response causes the disease
          • Positive corticosteroid effects
          • Inflammatory recurrences
          • Lack of antibiotic tx success
     o Unilateral vs bilateral disease
          • May be either
          • Recurrences may be either
          • If 2+ years pass without disease in second eye, vastly reduced chance of developing disease

Uveitis Classification: any cause of blood-ocular barrier breakdown

     o Primary: any etiology causing inflammation
          • Trauma: blunt vs penetrating
          • Infectious
               √ Bacterial: Brucella, Borrelia burgdorferi, Leptospira, Rhodococcus equi, Streptococcus
               √ Viral: EHV-1, EHV-2, Equine influenza, EVA, Parainfluenza type 3
               √ Parasitic: Onchocerca, Strongylus, Toxoplasma
          • Miscellaneous: endotoxemia, neoplasia, septicemia, tooth root abscess
     o Equine Recurrent Uveitis
          • Two or more episodes observed
          • Two+ years w/out an episode diminishes risk
          • Labeled: active / acute, quiescent, or end-stage
          • Three clinical syndromes
               √ Classic
                    • Most common
                    • Inflammation of iris, ciliary body, and choroid and adjacent cornea, anterior chamber, lens, vitreous, retina
                    • Attacks become more frequent / more severe
                    • Sequelae include blindness, phthisis bulbi, cataract, synechia
               √ Insidious
                    • Low grade inflammation not outwardly painful
                    • Gradual destructive effect
                    • Draft and appaloosa breeds
               √ Posterior
                    • Vitreous, retina, choroid and some anterior segment associated inflammation
                    • Blindness, vitreal cloudiness, retinal detachments
                    • Warmbloods, Europeans, draft breeds