prions

Question 1

prions

Answer 1

proteins that are infectious

Question 2

normal prion

Answer 2

PrPc, found in various tissues including neurons, alpha helical structure with predominance of alpha proteins sheets

Question 3

infectious prion protein

Answer 3

PrPsc, isoforms of the normal, same sequence of the PrPc differ in folding, Beta sheets more prominent than alpha , resistant to boiling, and proteases and radiation, and formaldehyde

Question 4

sporadic spongiform encephalopathy

Answer 4

due to spontaneous misfiling of cellular prions CJD disease

Question 5

genetic or familial spongiform encephalopathy

Answer 5

associated with specific mutations of PrPsc (familial CJD inherited)

Question 6

infectious/transmissable encephalopathy

Answer 6

may be acquired from eating infected meat, bone meal or iatrogenically
MOA-PrPsc from infected meat binds to PrPc of normal cells and causes conformational change and conversion to infectious form chain reaction

Question 7

characteristics of transmissible form

Answer 7

causes neurodegenerative Dz in animals and humans, path includes vacuolization, astrocytosis, and loss of neurons, these infectious particles will not induce any inflammatory changes or immune host response

Question 8

Scrapie histo

Answer 8

chronic, fatal nero DZ in goats, sheep will scratch on post for intense pruritis
transmission-oral route or from wounds, can be transplacental, vertical transmission still disputed; sip gene increases susceptibility sA short incubation pA is long so sAsA and sApA alleles die faster than pApA

Question 9

scrapie clinical signs

Answer 9

pruritis, bite flanks, self mutilation, muscle tremors, hind end paralysis

Question 10

premortem Dx

Answer 10

tonsillar biopsy and third eyelid testing histopath (should observe neuronal vacuolation and EM) NO inflammatory/immune response

Question 11

scrapie control

Answer 11

reportable, USDA based cleanup and monitoring plan

Question 12

bovine spongiform encephalopathy

Answer 12

in adult cattle, transmitted by meat and bone meal from slaughtered sheep, possible vertical transmission

Question 13

bovine spongiform encephalopathy clinical signs

Answer 13

incubations 2-8 hours,
NO pruritis
apprehension, hyperesthesia, incoordination, aggressive behavior
can observe vacuolization in grey matter on histology