Ocular Infections 2 Flashcards
Moraxella bovis
Gram negative rod - strict aerobe
Grows in mucus memb of URT/conj in carriers/infected
Causing keratoconjunctivitis in cattle
Predisposition for pinkeye - moraxella bovis
Host - lacking eyelid pigment, young, bull calf>heifer
Environment - UV exposure, dry/dusty, crowded condition
Transmission of moraxella bovis
Infected or carrier animals
Flying insects - mechanical transmission
Factors to m. Bovis virulence
Fimbriae or pili that mediate attachment of bacteria, vaccine targets pili action
- initial damage in eye is required
Hemolysin initiates toxic damage for corneal epithelial cells & damage epithelial via inflammatory infiltration
Range of ocular signs for pink eye
Conjunctivitis
Epiphora
Hyperemia
Profuse lacrimation
Photophobia
Blepharospasm
Keratitis
Corneal ulcers
Potential sequelae for m bovis
Globe rupture
Secondary infection - hypopyon
Treating m bovis
Could be self limiting
Subconjunctivial antibiotics - Pen G, ceftiofur
Systemic antibiotics - tetracycline, tulathromycin
Medicated eye patches
Controlling m bovis
Avoid predisposing factors
Isolate affected animals
Decrease stocking rates
Add shade/fly control
Vaccination
Fungal Extraocular infection
Periocular infection - blepharitis
- dermatophytes (ringworm)
Surface ocular infections are predominantly fungal keratitis
- commonly free living fungi transported to conjunctiva
More common in horses & production animals
Fungal keratitis
Aspergillus is the most common bacteria, directly inoculated into traumatized corneal epithelium
Virulence inhibit corneal neovascularization , reduced neutrophil infiltration & cell mediated phagocytosis = slowed healing
Feline herpes virus keratitis
URT and ocular infection commonly occur simultaneously
Rapid cell to cell spread, inducing cell lysis
Herpetic keratitis
Punctate ulcers - dots appearence
Dendritic /linear ulcer - fluorescence spreads linearly
Geographic ulcer - localized to a focal area affected
Interstitial ulcer - chronic manifestation
Symblepharon
Adhesion of conjunctiva to itself or cornea
Leads to vision loss/permanent damage
Common w severe cases of FHV1
Canine distemper virus
Can cause viral keratitis /conjunctivitis
Acute blepharitis / conjunctivitis - often 1st clinical sign
Acute keratoconjunctivitis
Intraocular disease - chorioretinitis, anterior uveitis, optic neuritis
canine adenovirus 1
Cause of infectious canine hepatitis - ocular manifestations are common
Rare disease due to good vaccine health
Presents w diffuse corneal edema - blue eye or anterior uveitis
Pathology due to deposition of immune complex on endothelial cells of eyes (type 3 immune reaction)
Intraocular infections
Due to local or systemic disease
Eye is often a target organ for systemic infectious agents
Ocular disease can be primary complaint
Intraocular infectious agents
Access eye via uvea /choroid or vascular tract
Posterior uveitis or chorioretinitis
Anterior uveitis
Leptospira
Intraocular bacteria
Anterior uveitis & equine recurrent uveitis
- kidney, liver, abortion
Enterbacterales
Intraocular
Gram negative bacteria - E. coli
Conjunctivitis, keratitis, dacrocystitis, anterior uveitis, etc
Histophilus somni
Gram negative Intraocular bacteria
Chorioretinitis, retinal detachment
Borrelia burgdorferi
Gram neg Intraocular bacteria
Anterior and posterior uveitis in dogs and panuveitis in horses
Brucella canis
Gram neg Intraocular bacteria
Anterior and posterior uveitis in dogs
Tick borne infections in Intraocular infections Ehrlichia canis
Ehrlichia canis
- ocular lesion occur frequently in dogs
Typical lesions
Uni- or bilateral anterior uveitis
Conjunctival episcleral hyperemia or hemorrhage
Miosis
Aqueous flare
Hypopyon
Keratitic precipitates
Posterior inflammation can also occur
Chorioretinitis, retinal haemorrhage, retinal detachment and optic neuritis
Rickettsia rickettsii Intraocular infection
Ocular lesion due to vasculitis - mostly presents as ocular hemorrhage
Infects endothelial cells
Feline corona virus
Cause of FIP, ocular manifestations are common in the dry form or chronic form of FIP
Presents as bilateral granulomatous anterior uveitis & chorioretinitis aka fibrin & keratic precipitates
Pyogran lesions around retinal vessels
Feline leukemia virus - ocular lesion
Intraocular infection - ocular lymphoma
Uveal tract is common site for metastasis
Mild uveitis, aqueous flare, keratitic precipitates
Leads to iris thickening & glaucoma
Canine distemper & adenovirus - Intraocular infection
CDV - presents as multi focal, non granulomatous chorioretinitis, optic neuritis / blindness
CAV - uveitis with miosis and aqueous flare, common in unvaccinated dogs
MCF - Intraocular infection
Highly variable clinical signs
Edema - eyelids, conjunctiva
Photophobia, lacrimation, conjunctivitis, progressive corneal opacity = corneal edema
Lymphocytic uveitis
Caused by gamma herpes that infects atypical host - sheep
Systemic fungal infections - histo Intraocular infection
Histoplasmosis - geographical region
More common in cats than dogs
Signs
Granulomatous chorioretinitis
Retinal detachment
Anterior uveitis
Secondary glaucoma
Optic neuritis
Histoplasmosis in cats
Conjunctival hyperemia
Corneoscleral inflammation
Corneal edema & vascularization
Anterior uveitis
Modular iritis
Blastomycosis - Intraocular infection
Geographic distribution - Mississippi, Ohio river, central Atlantic state
Cause of ocular lesion in 50% of dogs
Ocular lesions of blastomycoiss
Chorioretinitis - focal granuloma in fundus
Anterior uveitis
Endopthalmitis
Cryptococcus- Intraocular infection
Most common feline systemic mycolic infection
- common in cats, can occur in dogs
Wide spread distribution - bird/bat droppings
Presents with chorioretinitis w granulomatous inflammation & retinal detachment / optic neuritis
Toxoplasma gondii - Intraocular disease
Disease may be acute in young cats*
Common lesion is chorioretinitis
Multi focal dark gray infiltrates in tapetal fundus & fluffy white infiltrates the nontepetal fundus
Clinical signs/diseases caused by intraocular bacteria
Anterior uveitis
Vasculitis
Bacteria causing anterior uveitis
Lepto, B. Burgdorferi, H. Somni, B canis
Bacteria causing vasculitis/ uveitis
E. Canis, R. Rickettsia
Diseases caused by extra ocular bacteria
Blepharitis, conjunctivitis, keratitis
Bacteria causing blepharitis
Gram positive
Bacteria causing conjunctivitis
Mycoplasma, chlamydia, pasturella, moraxella
Bacteria causing keratitis
Gram positive, psudomonas Aeruginosa, moraxella
Conditions caused by intraocular fungi
Uveitis, chorioretinitis
Conditions caused by extra ocular fungi
Blepharitis
Fungi in Intraocular infections
H. Capsulatum, B. Dermatidis, C. Neoformans
Fungi in extra ocular infections
Dermatophytes
Diseases w intraocular parasites
Chorioretinitis
Diseases w extra ocular parasites
Blepharitis
Parasites for intra and extra ocular
Intra - t. Gondii
Extra - mites, Cuterebra
Intraocular Diseases caused by viruses
Uveitis, ocular LSA, chorioretinitis
Extraocular diseases caused by viruses
Keratoconjunctivitis
Causes of Extraocular blepharitis
Bacteria
Fungus
Parasites
Causes of uveitis in intraocular diseases
Bacteria - anterior or vasculitis
Fungus
Virus
Causes of keratitis
Bacteria
Fungus
Virus*
Specific causes for blepharitis
G+ cocci
Dermatophytes
Demodex
Cuterebra
Specific causes for keratitis
G+ cocci
P. Aeruginosa
Opportunistic fungi
Specific causes of conjunctivitis
Chlamydia
Mycoplasma
Pasteurella multocida
canine distemper virus
Specific causes of keratoconjunctivitis
Moraxella bovis
Feline herpes virus 1
Causes for corneal edema
Canine adenovirus 1