TV4101 - Bovine - Nervous 4 - Exotic Dz

Important Exotic Dz with nervous signs?

- bovine spongiform encephalopathy (BSE)

- rabies

- Aujeszky’s disease

Bovine spongiform encephalopathy (BSE)

Part of the family of?

Overview?

Transmissible spongiform encephalopathies (TSEs or prion diseases)

Transmissible, neuro-degenerative, fatal brain disease of cattle

Bovine spongiform encephalopathy (BSE)

Behaviour of Dz?

Central nervous signs, although variable, generally fall into

three categories (all of which may be present) which are?

CX onset insidious

- behavioural changes

- hyperaesthesia

- abnormalities in posture & gait

Bovine spongiform encephalopathy (BSE)

Behavioural changes?

Initially

• Placid → agitated or agro (e.g. kicking out at milking shed)

Later signs

- apprehension

- nervousness

- charging and pawing

- frenzy when confronted by obstacles

Bovine spongiform encephalopathy (BSE) - Hyperaesthesia

Describe it

Extreme sensitivity to sound and touch

• Cows may kick vigorously when trying to put on the milking

cups

Bovine spongiform encephalopathy (BSE) - Abnormal gait and posture

• Present as wide-based stance and low head carriage

• Kyphosis of the thoracic spine and lordosis of the lumbar

region (→ overall ‘S’ curvature of the vertebral column)

• Tremors, hindlimb ataxia, swaying & hypermetria when

walking

• Sharp turning may uncover problems such as knuckling of

the fetlocks, stumbling or falling

Bovine spongiform encephalopathy (BSE) - DX

Early clinical signs may be similar to?

Can also be sim to?

BSE also needs to be differentiated from?

Metabolic diseases, such as nervous ketosis and hypomagnesaemia

Ryegrass staggers

Polioencephalomalacia, hepatic encephalopathy, and other

causes of encephalitis and poisonings (e.g. lead, urea)

What is this?

Describe it

BSE

Histopathology of the brain with characteristic spongy

degen

BSE - Brain submission

What part of brain is submitted fresh to confirm BSE DX?

Obex region

Rabies

Typically transmitted by?

Contamination of a fresh wound with infected saliva, usually associated with the bite of a rabid animal (e.g. dog, bat)

Rabies

The forms?

The form in cattle usually?

Signs vary from excitatory (‘furious’ form) to paralytic

(‘dumb’ form)

In cattle, signs are usually of the paralytic form – the furious

form is relatively rare

Rabies

Prev in cattle?

Cattle are highly susceptible to rabies; however, only one or

two animals of the herd will be infected

Rabies - CX

Furious (rare) version signs?

Persistent bellowing with a hoarse, lowered-pitch voice, pawing at the ground, or aggression. There may also be aggression, increased sexual excitement & libido

Rabies - CX

Early signs?

Behaviour change, muzzle tremors,

abnormal posture, tenesmus, yawning, photophobia and pica

Partial paralysis of the pharyngeal muscles, teeth grinding

(odontoprisis or bruxism), and excess salivation

Rabies - CX

Late clinical signs can include?

As paralysis develops we see?

Opisthotonus, seizures, and widespread paralysis

Cattle knuckle over at the fetlocks, stumble, and fall frequently until they are unable to rise → then lapse into a coma and die

Rabies - Paralytic Form needs to be DDX from?

- botulism

- thrombo-embolic meningo-encephalitis (TEME)

- polioencephalomalacia

- intoxications such as lead, urea, and organophosphates

- cerebral babesiosis and theileriosis

Aujesky’s Dz (pseudorabies aka mad itch)

Overview?

Prevalence in cattle?

Viral disease causing encephalomyelitis and respiratory

infections

Sporadic (cattle are dead end hosts as primarily dz in pig)

Aujesky’s Dz (pseudorabies aka mad itch)

Most striking clinical sign is?

It manifests as?

Other signs?

Intense pruritus of a localised area of skin (‘mad itch’) – neck, trunk, and hindlimbs are most commonly affected (at least initially)

Licking, rubbing or gnawing → self-mutilate

High fever and sweating

Aujesky’s Dz (pseudorabies aka mad itch)

Within 24hrs we see?

Other signs?

Animal is recumbent, but is still able to rise and walk unsteadily

Clonic convulsions,

bellowing,

teeth grinding,

depression or aggression,

pharyngeal paralysis,

rapid shallow breathing, and cardiac irregularities

Aujesky’s Dz (pseudorabies aka mad itch)

Disease should be differentiated from:?

- nervous ketosis

- intoxications or other infections that produce severe neurological signs; e.g. rabies