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Flashcards in prions Deck (13):


proteins that are infectious


normal prion

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


infectious prion protein

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


sporadic spongiform encephalopathy

due to spontaneous misfiling of cellular prions CJD disease


genetic or familial spongiform encephalopathy

associated with specific mutations of PrPsc (familial CJD inherited)


infectious/transmissable encephalopathy

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


characteristics of transmissible form

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


Scrapie histo

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


scrapie clinical signs

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


premortem Dx

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


scrapie control

reportable, USDA based cleanup and monitoring plan


bovine spongiform encephalopathy

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


bovine spongiform encephalopathy clinical signs

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