Prion diseases Flashcards
Transmissible spongiform encephalopathies
Degenerative diseases of the central nervous system and brain the most accepted theory is that these illnesses are transmitted by prions which are essentially infectious misfolded proteins
What makes prions different
They are believed to consist only of protein and like any form of nucleic acid they are transmissible and cause numerous holes to form within the tissues of the central nervous system causing the affected tissues to develop a sponge-like spongiform appearance they listed no response from the host immune system
How do prions function
They cause certain proteins to miss fold into non-functional forms with a prion protein acting as a template guiding them is folding process the newly misfolded proteins are now preons themselves and can affect the folding of correctly folded proteins of the same time these proteins gradually accumulate in the body especially in nerve cells which subsequently die
Prions of considerable concern because
The diseases they caused a fatal they are resistant to many of the forms of disinfection that kill bacteria viruses fungi and spores
Scrapie
Neurological disease that affects sheeps and goats and does not appear to be a transmissible to humans different breeds of sheep have different susceptibility to the disease ranging from 0% to 80% and dissimilar breeds the name comes from the fact that the disease causes itching and so the sheep rub against rocks or tree scraping the fleece off their bodies
As the disease progresses amyloid plaques farm in the central nervous system of the infected animals the incubation period is generally 2-5 years no treatment is available and so the most common way to contain breakout is to quarantine and destroy the infected animals
Bovine spongiform encephalopathy (mad cow disease)
First identified in the 1980s in the UK for some time before this protein in the form of sheep and cattle bone meal and meat had been fed to cattle as a supplement without ill effect however in the mid-1980s there was a change in the way that the offal was processed and the unforeseen outcome was that contaminants were not destroyed and cattle became infected for the recycling of these contaminated animals may have amplified the effect
Possibilities on the source of the original infection of BSE
One one possibility is that the strain of scrappy was involved while other research suggests that BSE may have developed from a sporadic form of cattle prion disease called bovine amyloidotic spongiform encephalopathy
Variant creutzfeldt-jakob disease
A human disease believed to have Risen from BSE. They are thought to have been caused by the same agent and it is thought that vcjd arose from infection of humans with BSE the disease is assumed to have transmitted to human beings through food contaminated with BSE
Hans Gerhard creutzfeldt and Alphonse Maria Jakob
The variant croots felt Jakob disease was named after these neurologists
Other forms of TSE that have been detected in humans
Kuru Gerstmann straussler scheinker syndrome
These diseases can be grouped according to the manner in which they are quiet
Idiopathic (spontaneous) familial acquired
