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3. Food Animal 4 > Neurologic disease, Lameness, & Ocular disease > Flashcards

Neurologic disease, Lameness, & Ocular disease Flashcards

1
Q

Neurologic disease
* Common:
* Uncommon but reportable:

A

Common:
* Polioencephalomalacia
* Listeriosis
<><>
Uncommon but reportable:
* Rabies
* Scrapie

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2
Q

Polioencephalomalacia
* Presenting complaint:
* cause
* risk factors

A
  • Presenting complaint:
    > Single case, acting bizzare, blind
  • Caused by thiamine deficiency (B1)
  • Dietary + synthesized in the rumen
    <><><><>
  • Risk factors:
  • High level of carbohydrate (grain) in diet
  • Molasses
  • Toxic plants (bracken fern, horsetail)
  • High sulfur in water/feed
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3
Q

Polioencephalomalacia
* Clinical findings:

A
  • Stiff, stilted gait
  • Opisthotonus
  • Cortical blindness (still has PLR, no menace)
  • May go down
  • Die within 1-2 days if not treated
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4
Q

Polioencephalomalacia
* Post-mortem findings

A
  • Cerebral/cerebellar edema
  • Fluoresces with UV light
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5
Q

Polioencephalomalacia
* Treatment
* considerations, prognosis

A

Treatment
* Thiamine – TID x 3 days
* Dexamethasone to reduce cerebral swelling
* Flock level – can add to feed
<><><><>
* Early treatment is often successful
* If no response by 24h, poor prognosis
* No harm in treating with thiamine – add to treatment plan for all suspect cases

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6
Q

Listeriosis
- type of disease?
- prevalence?
- risk factors
- pathogenesis, lesions

A
  • Bacterial infection typically via ensiled feeds
  • Outbreaks of 2 – 10 % of the flock/herd
    <><>
  • Risk factors:
  • Silage/haylage with pH > 5.0
  • Contamination with dirt/manure
  • Forages fed on the ground, rodents, manure
    <><>
  • Entry via bloodstream or trigeminal nerve
  • Incubation 10 – 21 days
  • Microabscesses in brainstem
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7
Q

Listeriosis
* Clinical findings:
* prognosis
* who is susceptible?
* other signs sometimes?

A
  • Fever (> 40.0 C)
  • Unilateral cranial nerve signs
    > Circling, headtilt
    > Facial paralysis
    <><><><>
  • Often very severe
  • High case fatality
    <><><><>
  • Sheep/goats more susceptible than cattle
  • Also can be a cause of abortion
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8
Q

Listeriosis
* Treatment, control

A

Treatment:
* Antibiotics: oxytetracycline, penicillin or TMS
* Dexamethasone for cerebral swelling
* NSAIDs
* Extended nursing care
<><><><>
Control
* Metaphylactic treatment with LA oxytetracycline
* Remove source of infection
* Feed off the ground, keep silage face fresh

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9
Q

Rabies
- significance?
- signs?

A

– REPORTABLE!
* Local Public Health Unit if human exposure
* OMAFRA veterinarian if domestic animal exposure
<><><><>
* Lots of variation in clinical picture – acting weird
Typically seen in animal on pasture, but can be in a barn
* Exposure typically two weeks prior
* Treat all neuro cases as potentially rabid, even if
low on your list

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10
Q

Scrapie
- significance?
- what is it?
- pathogenesis, transmission, progression
- who is susceptible?

A

– REPORTABLE!
* Prion disease of both goats and sheep
* Named for the intense pruritis associated
* Sheep have a genetic predisposition or resistance to development of disease
* Infection of youngstock occurs at lambing (environmental contamination) when ewe is infected and has susceptible genetics
* Susceptible lambs can develop disease (2-5 yrs)
* Goats are very susceptible, and no genetic test exists

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10
Q

Scrapie
- clinical signs
- progression

A
  • Causes intense pruritis, increased grooming
  • Locomotor incoordination – high stepping, stumbling, abnormal head carriage
  • Progresses to recumbency within weeks-months
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11
Q

Scrapie diagnosis, control

A
  • Testing can be done using lymphoid tissue (live animal) or obex (dead)
  • Genetic testing of sheep for susceptibility
  • Sheep certification program
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12
Q

Lameness
* Common causes:

A

Foot disease complex:
* Foot scald
* Foot abscess
* Footrot
<><>
* CAE arthritis
* Joint ill in lambs and kids

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13
Q

Foot disease complex
- prevalence?
- signs?
- what diseases are part of this complex? pathogens?
- transmission / presence on farm

A
  • Lameness, usually > 5 % of the flock
  • Eat on knees
    <><>
  • Etiology:
  • Food scald – Fuscobacterium necrophorum, +/-
    benign strains of Dichelobacter nodus
  • Food rot – above + Dichelobacter nodus
  • Foot abscess – above + Trueprella pyogenes
    <><>
  • D. nodosus survives off food 1 week if warm and moist (not if hot/dry or cold)
  • Can only spread sheep/sheep if warm/moist
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14
Q

Foot disease complex
- pathogenesis

A
  • Moisture (muddy yard, wet pasture)
    > Softens interdigital skin
    > Invasion of tissues by
    Fusobacterium necrophorum +/- benign Dichelobacter nodosus
    <><>
    possible outcomes:
  • Deep invasion by trueperella pyogenes > foot abscess
  • interdigital dermatitis, foot scald
  • presence of more severe strains of Dichelobacter nodosus > Footrot
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15
Q

Foot disease complex
- what do the diseases in this complex look like?

A
  • Foot scald > Interdigital skin mascerated, inflamed, sole unaffected
  • Foot rot > Foot scald + underrunning of sole, mild to very severe
  • Foot abscess > Foot scald + deep involvement, may include P2/P3 joint
16
Q

Foot disease complex
- dx, tx?
- control?

A
  • Trimming helpful to diagnose, NOT a treatment
    <><><><>
    Treatment - foot bathing:
  • 10% zinc suplphate – stand 20-30 min, or 3% formalin walk through (painful) – twice 1 week apart
  • Hold on dry cement 1 hour
  • Isolate lame, return sound to clean pasture
  • House lame in dry lot, cull non-responders
    <><>
    (or) Treatment – antibiotics:
  • Long acting oxytetracycline (sheep/goats), or tilmicosn
    (sheep)
    <><><><>
  • Vaccination – available in other countries, efficacy?
  • Genetic susceptibility also involved
17
Q

Joint ill
- what is this?
- signs?
- associated with what other conditions?
- pathogens and their characteristics, disease, tx

A
  • Polyarthritis – many causes, often opportunistic
  • Causes stiffness, lameness
  • Associated with failure of passive transfer
  • Typically secondary to navel infection (add navel dip)
    <><><><>
    Erysipelothrix rhusiopathiae & Strep. spp.
  • Fibrinous polyarthritis in animals 2 weeks – 6 months
  • Bacteria present in soil
  • Respond well to penicillin if treated early
    <><><><>
    Chlamydia pecorum
  • Associated with pinkeye in lambs (kids, only pinkeye)
  • Responds well to tetracycline
18
Q

Ocular disease
* Common causes:

A
  • Entropion in lambs > Less common in goats
  • Contagious opthalmia/infectious
    keratoconjunctivitis > Sheep and goats
19
Q

Entropion
- what is this? who gets it?
- origin?
- tx?

A
  • Young lambs with blepharospasm, keratitis
  • One or both eyes
  • Inverted eyelids (lower more common)
  • Inherited – dominant (typically 1-5% prevalence) - Don’t breed
    <><><><>
  • Treatment – roll out eyelid
  • Inject bleb of penicillin
  • Clips, surgery
  • Repeated unrolling by hand
20
Q

Pinkeye
- what is this?
- signs? prevalence?
- pathogens?

A
  • AKA infectious keratoconjunctivitis, contagious opthalmia
  • Blinking, watery eyes, 15 – 30% affected
    <><>
  • Causative agents:
  • Mycoplasma conjunctivae – most common
  • Chlamydia pecorum - Associated with joint ill in kids/lambs
  • May see listeria causing conjunctivitis - ‘silage eye’
21
Q

Pinkeye
- usual presentation
- other associated conditions
- dx?
- tx?

A
  • Most have mild signs, resolve 3-4 days
  • Some will have keratitis, uveitis, corneal
    ulceration
  • Lab dx? Swabs conjunctiva in early cases
    <><>
  • Treatment:
  • Do not treat mild cases or will reoccur!
  • Need to develop immunity
  • If severe, single LA oxytet or tulathromycin
  • Irritation signs usually resolve quickly
22
Q

Take home messages
- important neuro diseases > causes, signs, tx, dx…

A
  • Polio is caused by a thiamine deficiency, associated with high grain feeding or high dietary sulfur– classic sign is cortical blindness, responds well if treated early
  • Listeria should be suspected for unilateral neurologic signs in animals on ensiled feeds – tx = antibiotics, steroids, NSAIDs, supportive care
  • Rabies (R) causes unusual signs – always keep this on your DDx list!
  • Scrapie (R) causes neurologic signs and intense pruritis – genetic susceptibility in sheep (+ control program), no genetic test in goats
23
Q

Take home messages
- foot scald, foot rot, foot abscess
> pathogens, lesions
- risks, transmission, control

A
  • Foot scald = infection of the interdigital area with F. necophorum +/- benign strains of D. nodus
  • Foot rot = foot scald + D. nodus, causes lesions on the sole
  • Foot abscess = foot scald + T. pyogenes, causes deep abscesses
  • Bacteria can live ~ 1 week in the environment when warm and moist
  • Treatment = footbathing or injectable antibiotics
  • Hold lame animals on a dry lot to avoid re-contamination, move healthy animals to clean pasture
24
Q

Take home messages
- joint ill
- entropion
- pinkeye
> who gets these, why? what to do?

A
  • Joint ill in lambs/kids – associated with FPT, navel infections – think about environmental contamination, colostrum program, navel dip
  • Entropion in lambs/kids – genetic, treatment = roll out eyelid
  • Pinkeye in sheep and goats – mild cases = conjunctivitis, severe = keratitis, uveitis, corneal ulceration – do not treat mild cases! Severe cases, use oxytetracycine or tulathromycin (systemic)

3. Food Animal 4 (16 decks)

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