A prion is an infectious agent composed of protein in a misfolded form. This is the central idea of the Prion Hypothesis, which remains debated. This is in contrast to all other known infectious agents (virus /bacteria/fungus/parasite) which must contain nucleic acids (either DNA, RNA, or both).

Nucleic acids contain the same elements as proteins: carbon, hydrogen, oxygen, nitrogen; plus phosphorous (C, H, O, N, and P).

Viruses. Viruses are assembles of organic molecules that consist of some short strands of RNA or DNA encapsulated within a protein shell. They are often referred to as if they were living organisms, but they don’t meet the criteria listed above for living things.

The prion appears to be the first infectious agent found whose transmission is not reliant upon genes made of DNA or RNA. An infectious structural variant of a normal cellular protein called PrP (prion protein) is known to cause spongiform encephalopathies.

Despite being composed by a single-stranded, circular, non-protein-coding RNA of just 246-401 nucleotides (nt), viroids can incite in their host plants symptoms similar to those caused by DNA and RNA viruses, which have genomes at least 20-fold bigger and encode proteins.

Prions can be deactivated in a steam autoclave using a temperature of 270 °F (132 °C) at 21 psi for 90 minutes. If the prion infected material is in a solution of sodium hydroxide, steam autoclave at 250 °F ( 121 °C) at 21 psi for one hour.

Immerse in 1N NaOH or sodium hypochlorite (20,000 ppm available chlorine) for 1 hour; remove and rinse in water, and then transfer to open pan and heat in a gravity displacement (121°C) or porous load (134°C) autoclave for 1 hour; clean; and subject to routine sterilization.

Prions cannot be destroyed by boiling, alcohol, acid, standard autoclaving methods or radiation, he said. Right now it is not clear what it takes to destroy prions, Moench said, but tests have shown some types may survive cremation temperatures of 2,000 degrees.

Universal Precautions. Prions are very stable molecules that do not break down easily. Normal sterilization procedures such as cooking, washing and boiling do not destroy them.

It is now established that scrapie and CWD are horizontally transmissible and can remain infectious after years in the environment. In one study, the scrapie agent remained infectious after burial in garden soil for three years.

Prions (proteinaceous infectious particles, an abnormal isoform of a normal cellular protein) cause Creutzfeldt-Jakob disease (CJD), scrapie and other related human and animal neurodegenerative diseases.

Furthermore, Prions are resistant to food-preparation treatments such as high heat and can find their way from the digestive system into the nervous system; recombinant Prions are infectious either bound to soil particles or in aerosols.

Prions & General Biosafety Recommendations In many instances, BSE prions can also be manipulated at BSL-2, however due to the high probability that BSE prions have been transmitted to humans, certain circumstances may require the use of BSL-3 facilities. All other animal prions are considered BSL-2 pathogens.

Prions are unprecedented infectious pathogens that cause a group of fatal neurodegenerative diseases by a novel mechanism. They are transmissible particles that are devoid of nucleic acid. Due to their singular characteristics, Prions emerge as potential danger since they can be used in the development of such weapons.

“Some researchers believe that the prions are formed when PrP associates with a foreign pathogenic nucleic acid. This is called the virino hypothesis. (Viruses consist of proteins and nucleic acids that are specified by the virus genome.

Prion diseases affect mammals, including cattle, sheep, goats and cervids (elk, deer and moose). Some prion diseases are infectious, and all are fatal.

Unlike diseases caused by viruses or bacteria, prion diseases are caused by infectious protein molecules that pass from animals to humans. Although differences between species makes it difficult for prion diseases to spread from one species to another, transmission does occur.

Animal prion diseases include scrapie of sheep and goats, bovine spongiform encephalopathy (BSE) or mad cow disease, transmissible mink encephalopathy, feline spongiform encephalopathy, exotic ungulate spongiform encephalopathy, chronic wasting disease of cervids and spongiform encephalopathy of primates.