Diseases In Humans And Animals Caused By “Proteinaceous Infectious Particles” Or Prions

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A few rare diseases such as Chronic Wasting Disease (CWD) in deer, bovine
spongiform encephalopathy (mad-cow disease), and Creutzfeldt - Jakob disease (CJD) in humans are caused by a transmissible agent. The identification of this transmissible agent has been the subject of much scientific inquiry and debate. This newly-discovered pathogen is called a prion.
Initially, the agent was thought to be a slow virus due to the unusually long incubation period, which can be up to forty years, between the time of exposure to the pathogen and the onset of symptoms. Further research into CJD, however, has indicated that this agent differs significantly from viruses and other conventional agents. Whereas viruses and other known infectious agents contain nucleic acids which house a cell's genetic material, researchers have been unable to identify any nucleic acids in the CJD agent. Additionally, the chemical and physical procedures that inactivate most viruses have proved ineffective in decreasing the infectivity of the CJD pathogen. In contrast, the procedures that degrade protein have been found to inactivate the pathogen.
As a result, a new theory regarding the transmissible agent has emerged and gained widespread acceptability. This theory holds that the transmissible agent is neither a virus nor other previously known infectious agent, but rather an unconventional agent consisting of protein. This newly-discovered pathogen is called a "prion", short for "proteinaceous infectious particle". Prions are thought to transform normal, benign protein molecules into infectious, deadly ones by altering the shape of the healthy molecules to the dangerous conformation. This transformation then induces a chain reaction to alter the shape of the other benign protein molecules into the deadly form. This new pathogen has been found responsible for four diseases that are terminal in humans.
Creutzfeldt - Jakob disease falls within a category of related ...