Diseases of Nervous System of farm animalsFor the students of Semester 9, 10 Faculty of Vet. Med.

byProf. /Ali Hassan Sadiek

Faculty of Vet. Med. Assiut Univ.

Sadiek59@yahoo.comE. mail:

لطلبة كلیات الطب البیطري-أمراض الجھاز العصبي لحیوانات المزرعة اعداد

علي حسن صدیق. د والتشخیص االكلینیكي والمعملي الباطنةأستاذ األمراض

جامعة أسیوط -كلیة الطب البیطري E. mail: Sadiek59@yahoo.com

Nervous system

Consist of :Nervous system 1-Central nervous system:

Brain & spinal cord

2- Peripheral nervous system :- Cranial Nerves.(12 pairs in all animal).- Spinal nervous (42 pairs in equines, 37 pairs in cattle, sheep &goats, 36 pairs in camels)

3- Autonomic nervous system :Regulating visceral organs.

Anatomy and physiology

Any pathological changes in structure leading to Modification or loss of function of this part .The nervous system (centrally & peripherally) is highly interactive and integrative , this to achieve the total coordination of body functions Which are necessary for survival

-Function of nervous system : Maintenance of mental, locomotor equilibrium. Control of different body functions in relation

to its surrounding environment.These functions achieved via:

function :function :SensorySensory--11Taste , smell , vision sensations

Motor function :Motor function :--22Voluntary & Involuntary movements Voluntary & Involuntary movements

::Visceral regulating functionVisceral regulating function--33Regulating the internal organs , glandsRegulating the internal organs , glands

Associating function :Associating function :--44Memory , intelligence Memory , intelligence

Clinical terminology of CNS

: inflammation of brain Encephalitis: inflammation of spinal cord Myelitis

: inflammation of both Encephalomyelitisbrain & spinal cord

: inflammation of meninges Meningitis: inflammation of brain &Encephalomeningitis

Its covering (meninges ) : inflammation of nerves Neuritis

: non inflammatory degenerative NeuropathyChanges of peripheral nerve endings .

Clinical terminology of CNS

: repetitive twitching of muscles Tremors: muscular contraction Spasm

: severe muscular contractions Convulsions: feeling ( sensation ) Aesthesia

: increase sensation Hyper aesthesia: no feeling (no sensation ) An aesthesia

: loss of consciousnessComa

-Important technical term :

: Loss of muscle tone (Incomplete Paresisparalysis)

: complete loss of muscular Paralysismotor function

: paralysis of both hind legs Paraplegia : paralysis of ( fore + hind ) Hemiplegia

limbs at one side.

Manifestations of nervous system -dysfunction :

Abnormal mental state-1a) Excited statemania Frenzy (severe mania )b) Depressed mental stateDepression Coma

abnormal behavior-2

Manifestations of nervous system -dysfunction :

Abnormal posture & gait-3Disturbance in sensation-4

Hyperesthesia. Hypoesthesia. Anesthesia

Involuntary muscular movement-5 Tremors Convulsions

Tetanus

Tetanus

Disturbance in posture and gait

Observed in:Encephalitis, meningitis, neuritis

Signs:Deviation of head, neck, Dropping of lips, eye lashes, cheeks,

earsOpisthotonus & Orthotonus.Dog sitting position.Head pressing

Disturbance in posture and gait

Head pressing & loss of sensation

Dog sitting position

Bovine ketosis

Paralysis:

Occur due to injury of locomotor center, it is either Spastic or flaccid paralysis.

Examples for disease assoc. with paralysis1- Trauma of motor pathway in the brain.2- Final stages of encephalitis/ or meningitis.3- Flaccid paralysis (Metabolic dis., Tick

paralysis, Snake venom, Botulism). 4- Spastic paralysis (e.g. Tetanus, tetany,

hypomagnesaemia)

Hyopmagnesemia (Lactation tetany)

Spastic paralysis

Tick paralysis

Boutulism

Disturbance of ANS

1- Dist. Of cran. Ns. (spasmodic colic, grass sickness, Vagus. Indigestion.

2- Dist. Of body sphinctres: Incont. Urine, feces, anuria

3- Blindiness:Central blindness (Brain injury)

decreased ability to avoid danger, +vepupilary reflex

Preph. Blind.: Avitaminosis A: inability to avoid danger, -ve pupilary reflex

Diagnosis of nervous system diseases

Case history. -1Clinical signs.-2Examination of animal-3

A)- General physical examination B)- Laboratory

- Hematology - Biochemical analysis - Serology

- C.S.F collection & analysisC)- Special methods

- Radiology & other imaging techniques

- Electro encephalography

Diseases of nervous system

Acquired Congenital

Infectious Non infectious

Bacterial (listeriosis )

Viral (rabies )

Parasitic (toxoplasmosis)

Fungal (cryptococcosis )

B.E.S ( scrapie )

Trauma

Ischemia

Cerebral anemia

Cerebral hemorrhage

Space occupying

Lesion & neoplasia

Intoxication as :lead

organo ph. cbd

Hypoplasia

Hydrocephalus

Meningeo –

encephalocele

Spinal dysgenesis

Cerebral anemia

Acute or chronic, depends on degree of O2 deprivation. Begins with excitation lasting to loss of function.

Causes: All anemia, hypoxia, it associate:Hydrocynide & nitrite toxicity.Heart failure (copper def. cows).Anesthesia.Pneumonia.At parturition in neonates.Brain injuries

Cerebral anemia

Signs:Acute hypoxia: loss of all brain function

(quadriplasia, loss of consiouness, muscle tremors, recumbency, convulsion, deaths or recovery.

Chronic hypoxia: General weakness, loss of equilb., blindness, tremors, convulsions.

Diagnosis: DD from hypglycemia,Treatments:O2 therapy, respiratory stimulants,

removal of causes.

Increased intracranial pressure, Brain edema

Associate other disease, it may be recoverable.

Causes:1- Vasogenic (Brain Hrge, meningitis,

trauma)2- Cellular toxicity (Salt poisoning in pigs).3- Brain edema: Closure of drainage of

cranial cavity fluids, it may congenital,)

Increased intracranial pressure, Brain edema

Signs: Central blindness observed within 12

hours of increased ICP, Fits of Opisothonus, Nystagmus, muscle tremors alternative with weakness and flaccidity.

Treatment: Hypotensive drugs (Thiamine, hypertonic

solutions, diuretics, cortisone “1 mg/kg bw)

Hydrocephalus

Encephalitis

Ruminants Equines

Cattle Sheep & Goats

Bacteria

Listeriosis, Hemophilus

Ricketsia, Clostridium

MHCV.,RabiesViruses:

.BSE

Toxoplasma: Parasitic

Staphylococus

Viscna.

Scrapie

Equine infectiousanemia

Signs of encephalitis

According to the causes and severity: Early stage: Excitation, violence, kicking, blowing,

yawing, convulsions, exophthalmoses, empty mastication, Salivation, Muscl. Tremors,

Later stage: Recumbency, fever, depression, tachycardia, change in animal behavour. Blindinss,incoordination , ataxia

Scrapie sheep

Encephalitis

Atrophy of cerebral cortex (CCN)

Rabies

Rabies

Rabies

Dianosis

It is difficult because of signs inter-related with other brain disease.

It could be confirmed on PM.Treatment:According to the cause, but generally you can use:1- Fluid therapy containg electrolytes.2- Narcotic in excitement stage and stimulant on

the depression stage.3-Antibiotics, Anti-inflammatory, antipyretics.4- Vitamin B cpx.

Brain Abscesses

Commonly in fattening calves and lambs. Its signs related to brain occupying lesions

Causes: usually hematogenous1-A. mallei of glanders lesion in lungs2-St. equi of strangles.3-Actinomyces & T.B.4-Fusobac.necrophrum from oropharynx.5-St. aureus in tick pyemia of lamb.6- Cryptococcosis (fungi )

Abscess of spinal cord

Cenurosis

Ruminants eat grass infested with dog feces containing the intermediate host T. multiceps, E.granulosus, reaching blood via intestine, invading brain & Sp. Cord forming cysts causing pressure onto neuronal and sensory centers..

Signs:

During the acute stage of latrvalmigration: blindness, ataxia, muscle tremors, dizziness. When adult cyst formed ( 2-5 cm):

Nystagmus, salvation, crazy running, convulsions, walking on circles.Cysts on spinal cord: Gradual

paralysis and inability to move or stand.

Cysticercus cerebralisThin walled cyst in brain

Diagnosis and treatment

Diagnosis:History of excess dogs on pastures and

farms.Signs of circling and incoordination.X-rayPost slaughtering examin. Treatment:Rafoxinide and other Antiparasitic with

little success.

Bovine Spongioform Encephalomylities (BSE)

Affect adult cattle & Transmit to human, resemble scrapie of sheep.

Causes: It may be the same of scrapie after feeding

cattle on food containing meat and bone extract of sheep infected with scrapie.

The lesion (spongiofrom vacuoles) was found in brain of infected cattle, man and sheep.

Isolated heat stable protein called prions.

BSE

Occurrence: It affect highly lactating cows and all

exposed cows as well. The disease is fatal with 100 %

mortality.Other cases observed in dogs, cats,

Tigers those imported from Britain

Scrapie Incoordination spastic

contracted Muscle

Nystagmus

Signs of BSE

Gradual increasing Change in animal behavior, posture, position, movement

Aggressive behavior, hyperesthesia, ataxiaRefuse to enter the milk allays, with violent

voices. Loss of orientation, aims, contracted ears,

muscle tremorsKicking, head pushing, attack of attendants

&other animals. Violent Licking, dragging of hind limbs. Falling & unable to stand.

Dragging of hind legs (BSE)

Postmortem exam.

Intracytop. vaculation of the neurons and grey matter & neutrophils of brain stem.

:DiagnosisDisease should be differentiated from all nervous system disease e.g.:Milk tetany, ketosis, rabies, lead poisoning

Histopathology

Secretions of prions

Secretions of prions in human

Treatment

No treatment, Condemenation of affected farms is the solution.

Prophylaxis: Avoid importing animals from endemic

countries. Avoid adding feed additives of animal origin

from infected countries. Notification of Authorities Avoid eating of animal products from affected

animals. Histopathological exam. Of the brain of any

suscpected animals.

Heartwater disease. Affects ruminants, caused by Ricktessia

(Cowardia ruminatum), transmitted by Ampyloma ticks.

Signs: Peracute form: Fever, diarrhea, convulsion

and death. Acute form: o Fever, nervous signs, o Pricking of eye leads.o Protruded tongue.o Biting of Jaw. o Walking in circles, convulsionso Extension of limbs in recumbent animals

Postmortem Exam,

Hydrothorax, hydropercardium, hydropleuraAscitisEnteritis, hepatomegaly,

splenomegaly, enlargement of L. nodes.Edema and brain Hrge.

( Heartwater)

Estrus ovis