Viral neurological diseases Flashcards
List some viral diseases affecting the neurological system
- Rabies
- Aujeszky’s disease
- Caprine arthritis and encephalitis virus
- Maedi visna virus
What are some other names for Aujeszky’s disease?
- Pseudorabies
- Match Itch
What is the aetiological agent of Aujesky’s disease?
- Suid herpesvirus -1*
- Varicellovirus*
- Herpesviridae*
Who is the main host of AD?
Swine
How is AD transmitted?
- Inhalation of the virus
- Ingestion
- Fomites
- Carcasses
- Latent carriers - pigs
How far can aerosol AD travel?
2km
How does AD affect the body (pathogenesis)?
- Virus enters the oropharynx
- Replicates in the epithelium of the nose, mouth, tonsils, oesophagus and upper respiratory tract
- Travels to the axoplasm of the cranial nerves
- Within 24 hours the virus can be isolated from the cranial nerve ganglia
What are the clinical signs of AD in cattle and sheep?
DEATH within 1-2 days
- Intense pruritus of a concentrated patch of skin
- Progressive weakness
- Recumbency
- Neurological signs
- Heart abnormalities
What are the post mortem signs of AD in ruminants?
Areas of oedema, congestion and haemorrhage of the spinal cord
How do we diagnose AD?
- Clinical signs
- Virus isolation
- Serology - ELISA, VNT and latex agglutination
- Immunofluoresence and immunoperoxidase
- PCR
What samples do we need to take for AD?
- Section of spinal cord that innervates the pruritic area
- Pruritic area of skin plus SC tissue
- Nasal swab, oropharyngeal tissue and tonsil biopsy
How do we treat AD?
Cull!
What is the aetiological agent of CAE?
- Lentivirus
- Retroviridae
How is CAE transmitted?
In kids, by drinking colostrum and milk from affected dams.
Horizontal transfer is less common, via direct contact, exposure of fomites and/or contaminated milk
Describe the pathogenesis of CAE
- Infiltration of lymphocytes, plasma cells and macrophages
- Localise in the synovial, CNS, lungs, mammry glands, kidneys, heart and lymphoid tissue
What are the clinical signs of the arthritis syndrome of CAE?
- Chronic polyarthritis of all joints (mainly carpal joints)
- Synovitis
- Bursitis
- Recumbency
- Loss of condition - poor coat
Describe the clinical signs of the encephalitic syndrome of CAE
- Progressive wasting
- Tremor
- Afebrile
- Hind limb ataxia progressing to paralysis of all limbs
- Opisthotonus of head and neck
- Head pressing
What other clinical signs can be seen in CAE?
- Pneumonia
- Mastitis
How do we diagnose CAE?
- Clinical signs and history
- Hisology of the CNS
- ELISA, AGID, PCR
What are the differentials of CAE?
- Listeriosis
- Toxoplasmosis
- Borna virus
- Enterotoxaemia
How do we treat CAE?
None - usually fatal
How do we prevent CAE?
Vaccination
Radical elimination of disease
What is the aetiological agent of Maedi-Visna?
- Lentivirus*
- Retroviridae*
How is MV transmitted?
- Ingestion of infected colostrum or milk
- Close contact - respiratory route
- Water contaminated faeces - rare
- Intrauterine spread - rare/negligable
Describe the clinical signs of Maedi?
RESPIRATORY SIGNS IN SHEEP
- Wasting
- Progressive dyspnoea
- Dry cough with no exudate
- Death from anoxia and secondary pneumonia
Describe the clinical signs of Visna
NEUROLOGICAL DISEASE OF GOATS
- Hindlimb weakness
- Trembling of lips
- Head tilt
- Ataxia, incoordination
- Paresis, paraplegia
Other signs of MV?
- Mastitis (but normal composition)
- Slowly progressive arthritis with severe lameness
- Poor weight gain
How do we diagnose MV?
- Clinical signs
- PCR
- ELISA, AGID
How do we treat MV?
None - supportive
How do we prevent MV?
NO VACCINE
- Only stock MV free animals
- Cull seropositive
- Quarantine and test before entry
- Isolate lambs from seropositive dams IMMEDIATELY
