Slow Viruses/ Agent disease Flashcards
how are slow virus or slow agent disease characterized by
incubation period period lasting for many months to years
- usually ends in death
what is the difference between convention and unconventional agent replication process
conventional: in vitro, produce CPE
unconventional: no CPE in vitro
conventional agents do what to the central nervous system
evoke inflammatory reaction of CNS
unconventional agents do not cause waht
no inflammatory response
no Ab response
no interferon production
what is Scrapie
disease of sheep marked by tremors and ataxia
- no deymyelination, no pleocytosis, no febrile reaction, no meningeal signs
what does Scrapie cause in gray matter
spongiform changes in gray matter- destruction of neurons
how does one get Scrapie
genetic and/or infectious in origin
physically what is Scrapie
PRION - aberrant protein PrPsc
PrPsc form what
scrapie associated fibrils found in brain
what does PrPc stand for
normal cell
PrPc is anchored to what
phosphatidylinositol glycan
- embedded in cell surface membrane
how does one get Human Ecephalopathies
genetically based disease
- familial transmission
how is Human encephalopathies transmitted
infecitous transmission
familial origins of prion disease results from mutations in the what normal gene? where is this gene located
PrP gene
human chromosome 20
what are mutations in the PrP gene
CJD
GSS
Scrapie agent is resistant to what
UV irradiation
ionizing irradtion
what inactivates scrapie
chlorox ( sodium hypochlorite)
what is the only immunity the body has to scrapie
no immunity except for Ab to neurofilaments
how is scrapie’s transmissible
animals
what does not inactivate scrapie agent
formalin- brain tissue in formalin still infectious after 7 years - threat to pathologists
where does PrP sc go in the cell
accumulates in cells and is deposited in cytoplasmic vesicles or it can be released from the cell surface
how can PrPsc cause disease and be transmissible
abnormal tertiary level folding
- causes CNS degernation
- interact with normal PrPc
what is kuru
spongiform encephalitis in man similar to scrapie in sheep
clinical symptoms of kuru
tremors little or no demenita incoordination ataxia somnolence sleepiness
how has Kuru been passed
eating body parts of dead people who have it
clinical symptoms of Creutzfeld-Jacob disease
presenile dementia ataxia myoclonic fasciculations semiconsciousness involuntary contraction of groups of muscle fibers
what is found in the infectious tissue of Creutzfeld-Jakob disease
SAF
how is Ceutzfeld-Jakob transmitted
corneal transplants
contaminated brain electrodes
maybe sheep to human
what are diseases that are possibly caused by unconventional agents
alpers
picks
alzheimers
what are 2 diseases caused by conventional agents (viruses)
Subacute sclerosing panencephalitis (SSPE)
Progressive Multifocal Leukoencephalopathy (PML)- papovavirus
what happens inside the body for SSPE
progressive demyelination degenerative neurological disease fatal enormous increase in hypertrophic astrocytes proliferation of microglial cells
what is a causative agent for SSPE
measles virus
what are 2 viruses associated with PML
SV40
JC
PML is associated with what disorders
lymphoproliferative disorders
