Diseases Of Nervous System Of Farm Animals By Ali Sadiek

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

by Prof. /Ali Hassan Sadiek Faculty of Vet. Med. Assiut Univ. E. mail: [email protected]

‫ ﻟﻄﻠﺒﺔ ﻛﻠﯿﺎت اﻟﻄﺐ اﻟﺒﯿﻄﺮي‬- ‫أﻣﺮاض اﻟﺠﮭﺎز اﻟﻌﺼﺒﻲ ﻟﺤﯿﻮاﻧﺎت اﻟﻤﺰرﻋﺔ‬ ‫اﻋﺪاد‬

‫ ﻋﻠﻲ ﺣﺴﻦ ﺻﺪﯾﻖ‬.‫د‬ ‫أﺳﺘﺎذ اﻷﻣﺮاض اﻟﺒﺎﻃﻨﺔ واﻟﺘﺸﺨﯿﺺ اﻻﻛﻠﯿﻨﯿﻜﻲ واﻟﻤﻌﻤﻠﻲ‬ ‫ ﺟﺎﻣﻌﺔ أﺳﯿﻮط‬-‫ﻛﻠﯿﺔ اﻟﻄﺐ اﻟﺒﯿﻄﺮي‬ E. mail: [email protected]

Nervous system Nervous system Consist of : 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: 1- Sensory function : Taste , smell , vision sensations

2- Motor function : Voluntary & Involuntary movements

3- Visceral regulating function : Regulating the internal organs , glands

4- Associating function : Memory , intelligence

Clinical terminology of CNS Encephalitis : inflammation of brain Myelitis : inflammation of spinal cord Encephalomyelitis : inflammation of both brain & spinal cord Meningitis : inflammation of meninges Encephalomeningitis : inflammation of brain & Its covering (meninges ) Neuritis : inflammation of nerves Neuropathy : non inflammatory degenerative Changes of peripheral nerve endings .

Clinical terminology of CNS Tremors : repetitive twitching of muscles Spasm : muscular contraction Convulsions : severe muscular contractions Aesthesia : feeling ( sensation ) Hyper aesthesia : increase sensation An aesthesia : no feeling (no sensation ) Coma : loss of consciousness

Important technical term :Paresis : Loss of muscle tone (Incomplete paralysis) Paralysis : complete loss of muscular motor function Paraplegia : paralysis of both hind legs Hemiplegia : paralysis of ( fore + hind ) limbs at one side.

Manifestations of nervous system dysfunction :1- Abnormal mental state a) Excited state  mania  Frenzy (severe mania ) b) Depressed mental state  Depression  Coma

2- abnormal behavior

Manifestations of nervous system dysfunction :3- Abnormal posture & gait 4- Disturbance in sensation  Hyperesthesia.  Hypoesthesia.  Anesthesia

5- Involuntary muscular movement  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, ears  Opisthotonus & 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 paralysis 1- 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, +ve pupilary reflex  Preph. Blind.: Avitaminosis A: inability to avoid danger, -ve pupilary reflex

Diagnosis of nervous system diseases 1- Case history. 2- Clinical signs. 3- Examination of animal A)- General physical examination B)- Laboratory - Hematology - Biochemical analysis - Serology - C.S.F collection & analysis

C)- Special methods

- Radiology & other imaging techniques - Electro encephalography

Diseases of nervous system Acquired Infectious

Congenital Non infectious

Hypoplasia

Bacterial (listeriosis )

Trauma

Hydrocephalus

Viral (rabies )

Ischemia

Meningeo –

Parasitic (toxoplasmosis)

Cerebral anemia

Fungal (cryptococcosis )

Cerebral hemorrhage

B.E.S ( scrapie )

Space occupying Lesion & neoplasia Intoxication as :lead organo ph. cbd

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 Cattle

Equines Sheep & Goats

Bacteria Listeriosis, Hemophilus Ricketsia, Clostridium Viruses: Rabies, MHCV. BSE. Parasitic: Toxoplasma

Staphylococus Viscna. Scrapie

Equine infectious anemia



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 hematogenous 1-A. mallei of glanders lesion in lungs 2-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 latrval

migration: 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 cerebralis Thin walled cyst in brain

Diagnosis and treatment  Diagnosis:  History of excess dogs on pastures and

farms.  Signs of circling and incoordination.  X-ray  Post 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, ataxia  Refuse to enter the milk allays, with violent voices.  Loss of orientation, aims, contracted ears, muscle tremors  Kicking, 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. Diagnosis: Disease 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 o o o o o

Fever, nervous signs, Pricking of eye leads. Protruded tongue. Biting of Jaw. Walking in circles, convulsions Extension of limbs in recumbent animals

Postmortem Exam,  Hydrothorax, hydropercardium,

hydropleura  Ascitis  Enteritis, hepatomegaly, splenomegaly, enlargement of L. nodes.  Edema and brain Hrge.

( Heartwater)

Estrus ovis