18 - Prions Flashcards
Prion outbreak: disease was linked to using ______________ and rapidly became endemic in the UK and from there spread to other countries
slaughtered carcasses in animal feed
It is estimated that ________ infected animals entered the food supply chain without being detected
3.5 million
When the disease gets transmitted to humans it is known as ____________
variant Creutzfeldt-Jkob disease (vCJD)
The practice of feeding agricultural waste to animals was banned in ____, cases after this were likely due to cross-feeding, and cross contamination.
1988
Prionsareinfectious agents composed entirely of a___________ that can fold in multiple abstract ways and at least one of which is transmissible to other prion proteins. This leads to a disease that is epidemiologically comparable to the spread of ________
protein material
viral infection
Prion composed of the prion protein (Prp) are believed to be the cause of _______________ among other diseases
transmissible spongiform encephalopathies (TSEs)
Prions cause fatal ______________ in humans and animals by converting the cellular prion protein P____ into the aggregation-prone _____ .
neurodegenerative diseases
PrPC
PrPSc
____________: biological material that has been obtained through sampling of infected individuals
isolate
_________: the term corresponds to a defined prion population isolated from one specified animal
strain
________: refers more particularly to a combination of biochemical parameters (mainly to the size of the unglycosylated PrPSc fragment after proteinase K partial digestion) that are independent from the host.
Type
Each TSE disease shares some common characteristics:
- long incubation periods ranging from years to decades
- illness of weeks to months with invariable progression to death
- accumulation in the brain and other tissues of fibrillar amyloid protein aggregates (PrPTSE)
- Pathological changes confined to the CNS
- The absence of an immune response (cause it is only a misfolded protein - not recognized as foreign by the immune system)
T or F: There are some biological differences in terms of pathogenesis, transmission, and distribution of infectivity in tissues
T
Different strains of TSEs affect different humans and animals:
- scrapie affects ______ and _____
- chronic wasting disease affects ________
- transmissible mink encephalopathy affects ____
- kuru only affects ______, but really was only confined to Papua new Guinea cannibals
sheep and goats
cervids
mink
humans
T or F: CWD first appeared in North America in captive animals in 1969 when biologists conducting a physiological study recognized that their animals often died with a syndrome of weight loss and behavioral changes
T
CWD is a _______ developing disease, with prolonged _______________
slowly incubation periods (2-4 year incubation time)
In most prion diseases, ______ and infectivity are restricted mainly to the brain. However, in _____, PrPSc can be found in many _______ tissues, body fluids, and excreta, facilitating ____________
PrPSc
CWD
extraneural
horizontal transmission.
Name some natural CWD hosts:
- elk
- mule deer
- white-tailed deer
- moose
- reindeer
_______ and _______ deer are also susceptible to CWD via experimental transmission
red deer and fallow deer
T or F: A unique aspect of CWD is that unlike other prion diseases, indirect transmission also occurs via CWD prion deposition into the environment from urine, feces, and saliva onto and into water, soil, and plants.
Cervids and other animals likely consume prions contained in these reservoirs and become infected.
T (deers don’t have to ear each other to become infected)
BSE =
Bovine spongiform encephalopathy
Is it considered natural for a cow to eat the nervous system of another cow?
no
It is suggested that sporadic disease of BSE may be cause by a __________ mutation
genetic
Once cattle were infected, there is evidence to indicate that epidemic was perpetuated by _______________
feeding BSE-contaminated meat and bone meal to cattle
In BSE, the stability of the protein shows an unusual resistance to destruction, protein can survive:
- heating under pressure at 121C
- exposure to dry heat at 600C
- immersion in 0.1N NaOH
- immersion in 0.5% bleach
