Farm animal ophthalmology Flashcards
(36 cards)
When do you get transplacental infection of bovine foetus?
125-175d gestation (numerous congenital defects possible)
Possible in utero effects - IBR
- retinal atrophy
- optic neuritis
- cataract
- micropthalmia with retinal dysplasia
- these often –> blindness
Other than ocular lesions, how does IBR affect bovine feoetus?
- URT –> red nose and eyes
- eye lesions: conjunctivitis (hyperaemia + oedema), diffuse corneal oedema possible t
- usually presents with bilateral serous ocular discharge
Tx - IBR
symptomatic
Prevention - IBR
- vaccination
- biosecurity
What is OVH2? Transmission?
Ovine herpesvirus 2
- transmitted sheep to cattle
CS - OBH2 in cattle
- GI signs: anorexia and diarrhoea
- agalactia
- pyrexia (41-41.5)
- RT signs: mucopurulent ND, severe dyspnoea with stertor d/t obstruction of nasal cavities with exudates
- enlarged LNs
- ocular signs (common, corneal opacity, unilateral then bilateral, hypopyon may develop (often die first)
Define hypopyon
= leukocytic exudate in AC, usually accompanied by red conjunctiva and underlying episclera. a form of anterior uveitis
Dx - OVH2
viral DNA by PCR
Tx - OVH2
frequently PTS
Colloquial names - Moraxella bovis
= New Forrest eye, Pink eye
What type of bacteria is Moraxella bovis?
- gram negative
- aerobic
Where is Moraxella bovis found?
in eyes of many recovered and apparently normal cattle
Outline disease - Moraxella bovis
- mutifactorial
- cattle are carriers
- Fomites: flies, dust, long grass (thus common in summer/ early autumn)
- tends to be unilateral
CS - Moraxella bovis in cattle
- tearing and photophobia
- conjunctival hyperaemia and chemosis
- corneal changes may follow (oedema, ulcer, abscess, hypopyon)
- vision loss may develop within 3 d
Tx - Moraxella bovis
- early (to resolve problem and prevent spread)
- cloxacillin
- TC
- bulbar conjunctival injection
- no topical steroid (corneal ulcer risk)
- OTHER: isolate infected animals, fly control
What type of bacteria is Listeria monocytogenes and where is it found?
- gram positive
- microaerophilic
- in poorly fermented alkaline silage
CS - Listeria monocytogenes
- Encephalitis and abortion
- CN deficits
- OCULAR: strabismus and nystagmus
- ‘silage eye/ red eye’ (originates directly from silage, innoculation when animal eats and head goes into silage)
Dx - Listeria monocytogenes
- CS
- Time of year
Tx - Listeria monocytogenes
- Antibiosis : chlortetracycline or penicillin, in early stages (IM, subconjunctivally)
- NSAIDs to reduce inflammation
What neoplasia can affect bovine eye?
SCC (malignant)
Outline SCC in bovine eyes
- animals > 5 yo usually
- low pigment is a predisposing factor (common with white heads = Hereford, associated with actinic radiation = sun)
Lesions stages - SCC
- plaque (hyperplastic epithelium)
- papilloma (non-malignant, high regression rate)
- SCC in situ (non-invasive)
- invasive SCC (past the epithelium’s lamina propria)
Name 3 possible ocular locations for bovine SCC
- sclera
- nictitating membrane (TE)
- eyelid
