Feline Infectious Uveitis

he uveal tract is composed of the iris, ciliary body and choroid.Uveitis in cats can be induced by either exogenous or endogenous causes.The most common causes of exogenous uveitis include trauma, corneal ulceration, and penetrating wounds which can usually be diagnosed on clinical examination.Endogenous uveitis can be classified as parasitic, infectious, lens-induced, neoplastic or idiopathic.Excluding lens-induced and neoplastic causes, there are no pathognomonic clinical ophthalmic changes associated with uveitis in the cat.Independent of etiology, aqueous flare, iritis, keratic precipitates, hyphema and hypopyon commonly develop in the anterior chamber.The choroid can be inflamed with or without concurrent anterior segment involvement.Appropriate management of uveitis in the cat is important to avoid lens luxations, cataract formation and glaucoma, three common sequelae to intraocular inflammation.The most common infectious agents proposed to cause uveitis in naturally-exposed cats of the United States include Toxoplasma gondii, feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline infectious peritonitis virus (FIP), and mycoses including cryptococcosis, histoplasmosis, blastomycosis, coccidioidomycosis and candidiasis.Uveitis has been induced in cats following inoculation with FIV, FIP and T gondii.Recently, some information suggests that Bartonella henselae and herpesvirus 1 can induce intraocular inflammation in some cats.Clinically, these agents induce intraocular changes that are indistinguishable on ophthalmoscopic examination, particularly if only the anterior uvea is inflamed.