TSE

Question 1

give examples of TSEs

Answer 1

sheep and goats: scrapie, atypical scrapie
Mink: minl spongiform encephalopathy
Deer/elk: chronic wasting disease
Cattle: bovine spongiform encephalopathy
cats: feline spongiform encephalopathy

Question 2

what are Transmissible spongiform encephalopathies

Answer 2

• neurological disorders
• neuronal loss
• invariably fatal
• very long incubation periods
• caused by misfolded prion protein

Question 3

discuss the role to prions in the development of TSEs

Answer 3

PRPc, a prion protein found in all mammals and has no known function, but high levels of expression within the CNS, misfolds. the prion, which is mainly composed of alpha helixes, changes conformation to beta sheets which makes the protein more rigid. this can happen one of three ways:
- spontaneously
- inherited (genetic)
- acquired (ingestion, contact)

it is not treatable, there is no cure and it can have VERY long incubation periods (time from exposure to symptoms)

Question 4

what are some properties of prions
‘Especially in terms of removing them from environments or animals

Answer 4

• relatively insoluble
• self catalytic conversion
• exceptionally high stability
• resistant to proteases
• resistant to heat treatment
• resistant to UV

making it difficult to decontaminate premises or clinical setting and allowing it to survive in environmental reservoirs
there is NO CURE or TREATMENT

Question 5

how do you test for TSEs

Answer 5

the primary site of pathogenetic prions is found in the obex, a site in the brain stem caudal to the medulla oblongata.
HOWEVER, different strains have been found in the cerebrum and cerebellum instead.
only way tp test definitively is with post mortem sample of brain
tests: histology, immunohistochemistry, Immunoassays (Western blots and ELISAs)

Question 6

what are clinical signs of TSEs

Answer 6

• weight loss
• subtle behavioural chanhes
• licking lips, grinding teeth, scratching
• pruitis (scrapie)
• posture, gait changes
• ataxia/tremors
• none, animal found dead

Question 7

which strain of TSE is zoonotic

Answer 7

BSE and FSE

Question 8

how is TSEs spread

Answer 8

BSE, FSE etc are difficult to spread among hosts (requires ingestion, transmission via medical procedure)
Scrapie and CWD are transmitted through direct contact an environmental reservoirs

Question 9

how is TSE controlled

Answer 9

• culling/cohort culling
• feed ban for ruminant material
• older cattle banned from human food chain
• ban of specific risk material from food chain
• export ban
• surveilance
• breeding resistant genotype

Question 10

what are contagious materials for scrapie in sheep

Answer 10

• skin
• feces
• urine
• saliva
• placenta (very contagious)
• blood
• milk