bovis - Articles
Bovine iritis
Synonym(s): Silage eye, uveitis
Introduction
- Cause: local immune/hypersensitivity reaction of the iris (and surrounding tissues), thought to be associated with an infective agent, most commonly Listeria spp.
- Signs: corneal opacity, miosis, corneal/scleral neovascularisation, ptosis, pannus, hypopyon, lacrimation, serous to mucopurulent ocular discharge, photophobia, palpebral edema, blindness.
- Diagnosis: history (exposure to silage/Listeria), clinical signs.
- Treatment: bulbar sub-conjunctival administration of corticosteroid and antimicrobial with Gram +ve spectrum, +/- topical ophthalmic antimicrobial preparation.
- Prognosis: fair to good.
Geographic incidence
- Worldwide (UK over-represented in literature reports).
- Associated with silage/conserved forage feeding, leading to exposure to Listeria spp.
Age predisposition
- Weaned and older.
Breed/Species predisposition
- No known breed predisposition.
Pathogenesis
Etiology
- Hypersensitivity/local immune reaction of the iris, thought to be in response to an infective agent, most commonly associated with Listeria spp Listeria monocytogenes presence.
- Listeria likely to have gained access to the eye either by direct infection across the conjunctival sac or from the gingival margins by trigeminal nerve migration.
Pathophysiology
- Iritis and miosis can lead to complete uveal tract inflammation and uveitis with keratic precipitate (KP) and hypopyon developing.
- Marked pannus and palpebral edema can predispose to secondary infections.
- Chronic/refractory cases may require enucleation Surgery: enucleation (rare).
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed Papers
- Recent references from PubMed and VetMedResource.
- R A Laven & K R Lawrence (2006) An outbreak of iritis and uveitis in dairy cattle at pasture associated with the spplementary feeding of baleage. NZ Vet J 54 (3), 151-152 PubMed.
- Erdogan, Hidayet Metin (2010). "Listerial keratoconjunctivitis and uveitis (silage eye)." Veterinary Clinics: Food Animal Practice 26.3: 505-510. PubMed
Other sources of information
- Andrews A H, Blowey R W, Boyd H & Eddy G (2008) Bovine Medicine. 2nd edn. In: Ocular Diseases. pp 923.
- Blowey R W & Weaver A D (1991) A Colour Atlas of Diseases & Disorders of Cattle. In: Ocular Disorders. pp 136.