Transmissible Spongiform Encephalopathies Flashcards
1
Q
Name the 7 TSEs
A
- BSE
- Scrapie
- Chronic Wasting Disease
- Transmissible Mink Encephalopathy
- Feline TSE
- Exotic Ungulate Encephalopathy
- CJD, vCJD, GSS, FFI
2
Q
Clinical signs of scrapie
A
- progressive neurological signs
- subtle behavioral changes
- scraping behavior
- incoordination
- weight loss
- biting feet and limbs
- lip smacking
- gait abnormalities
- trembling
- recumbency
3
Q
Which scrapie strain is most common in USA?
A
strain 171 (change in protein genotype at codon 171)
increased susceptibility with QQ as opposed to QR or RR
4
Q
Pathogenesis of scrapie
A
- infectious prions ingested, cross mucosa at tonsils and Peyer’s patches
- prions accumulate in macrophages in lymph nodes
- spread to CNS via retrograde transport in nerves
- accumulation of PrPsc
5
Q
Diagnosis of scrapie
A
- post-mortem histopathology of brain
- 3rd eyelid biopsy with IHC
- ELISA (not currently approved)
6
Q
Clinical signs of chronic wasting disease
A
- cachexia and changes in behavior
- ataxia, wide based stance, head tremors, somnolence
- less eating
- salivation and drooling
7
Q
Pathologic changes from chronic wasting disease
A
cachexia
aspiration pneumonia
8
Q
Histopathology of lymphoid tissues in chronic wasting disease
A
PrPsc demonstrable before neuropathology is detected
9
Q
Histopathology of CNS
A
- earliest lesions in parasympathetic vagal nuclei (at obex)
- IHC detection of PrPsc
- vacuolar change in astrocytes and neurons
- demyelination and astrocytosis
10
Q
Diagnostic tests for chronic wasting disease
A
- histopathology of brain
- IHC for PrPsc in affected brain regions, lymph nodes, or tonsils
- ELISA of medial retropharyngeal lymph node only (90% sensitivity)
11
Q
Diagnosis of BSE in cows
A
IHC for PrPsc on brain stem at obex
no other tests are currently approved
