TSE's

Question 1

What does TSE stand for?

Answer 1

Transmissible spongiform encephalopathies

Question 2

What are common characteristics of TSE’s?

Answer 2

• Long incubation period
• Progressive and invariably fatal
• Holes in brain give spongiform texture
• No signs of fever
• No signs of inflammation
• No antibody response
• No signs of a pathogen with a genome
• No sign of infection

Question 3

How is scrapie characterised?

Answer 3

Ataxia, tremors, rubbing/ scratching, loss of condition & death in 1-3 months.

Question 4

What are the transmission routes for scrapie?

Answer 4

• Mother to offspring in utero
• Parent to offspring: from infected birth tissues
• Adult to adult
• From the environment where infected sheep have lived previously
• Needle contamination

Question 5

Which PrP genotype is the highest risk for scrapie?

Answer 5

VRQ/VRQ

Question 6

What led to the national scrapie plan being set up?

Answer 6

I was suggested that BSE in sheep might transmit naturally, like scrapie; and perhaps could be in joints for human consumption
- This question drove a determination by the UK government to control/eradicate scrapie in the UK sheep population – by genetic means

Question 7

What were the two main components of the national scrapie plan?

Answer 7

• Scrapie-free farms (voluntary scheme): Lambs and sheep genotyped at no cost, under condition that those bearing VRQ allele will be culled.
• Scrapie-infected farms (compulsory scheme): Slaughter of entire flock (with later restocking) OR compulsory genotyping of entire flock, followed by culling of all animals encoding VRQ (except ARR/VRQ)

Question 8

How is Bovine Spongiform Encephalopathy characterised in cattle?

Answer 8

Ataxia, nervous or aggressive behaviour, loss of condition & death in 1-6 months

Question 9

How is Bovine Spongiform Encephalopathy transmitted?

Answer 9

Orally - from a meat and bone meal refed to cattle which contained infected carcass material

Question 10

What is ‘meat and bone meal’ and why was it fed to cattle?

Answer 10

Cattle were fed supplementary protein, as “meat & bone meal” made by rendering animal carcasses

Question 11

What BSE controls were implemented to prevent transmission?

Answer 11

• Ban on the use of ruminant-derived protein in ruminant feedstuffs
• Specified risk material control – remove parts of animal most likely to contain BSE from food chain
• Over 30 months rule: no cattle to enter food chain if over 30 months old

Question 12

What are the clinical signs and pathology of chronic wasting disease?

Answer 12

• Loss of condition, standing apart from herd, listlessness, ataxia, nervousness, excessive drinking and urination
• Aspiration pneumonia is common cause of death
• Incubation period of ~ 16 months

Question 13

How is chronic wasting disease transmitted?

Answer 13

• urine and saliva
• direct shed into the environment which is eaten by other animals
• Lateral (direct animal-to-animal) transmission also occurs.

Question 14

Name the only TSE of wild animals

Answer 14

chronic wasting disease

Question 15

What are the clinical signs of Variant Creutzfeldt-Jakob Disease?

Answer 15

Psychiatryic: depression, anxiety, delusions, hallucinations
Neurological: ataxia, chorea (dance-like motion of twisting & turning), myoclonus (involuntary muscle spasm), dementia