We have all heard of viruses, bacteria, fungal and protozoan induced infection. Most of them curable under proper diagnosis, some very common to us and while others are more feared diseases like AIDS and cancer. However, these diseases also have some sort of medication and care which can be given to patients for their recovery. But today let’s talk about the lesser known but most dangerous kind of infectious particle known to humans. Its name is prions and scientists hardly know anything about it.
It all started in 1982, when Stanley Prusiner discovered a particle which had no DNA or RNA, the basis of every living organism in the world. These particles were just proteins and couldn’t even be classed as living or dead. The particles were infectious agents and were given the name prions. Some scientist resisted the fact that prions exists because it disrupts the universal rule that proteins are formed from transcription and translation of nucleic acid.
Our brain is the most complex organ of our body. Much of things about the functions of the brain is unknow to us till now. There is a protein present in the cytoplasmic membrane of the cells in our brain, known as prp. The exact functionality of the protein is unknown to us but is speculated that it’s associated with then normal functioning of the brain. The sequence of amino acid in PrP allows the protein to fold into two stable tertiary structures: The typical cellular PrP (C-PrP) functional structure has multiple α-helices, whereas β-pleated sheets are the disease-causing forms of prion prp (P-PrP). Just like the saying goes: one rotten apple spoils the lot, in the same way one disease causing prp causes the other normally functioning prp to transform into its disease-causing form, in a process known as templating. The neurons stop functioning correctly and finally die as prion prP aggregates spread all over the brain. This gives rise to a disease known as bovine spongiform encephalopathy. The disease causes degenerate a person’s life within months. It causes amnesia, mental retardation, paralysis and death. The zoonotic epidemic in Europe which caused the cows to behave unusually, and die was also cause by prions and is known as the mad cow disease. It affects a variety of animals, and its form of transmission is through foods which have been infected with prions. It causes scrapie in sheep, and chronic wasting disease in deer. Prions are associated with Alzheimer’s, Parkinson’s, Creutzfeldt–Jakob disease and even cancer.
The thing that makes prions most dangerous is the fact that once you have been infected with a prion disease, it is 99% of the times, going to kill you. There are no cures for prion diseases. Cooking doesn’t kill prions, nor does our standard sterilization method, practised worldwide. In other words, alcohol, soaps, detergents, acid, even fire does not kill it. After a number of research, we found that it takes much more than rapid and intense heat treatment, at 482 degrees Celsius continuously for 4 hours to finally deactivate it.
So why isn’t prion, which is such a dangerous particle, not the leading cause of disease in the world? Well, lucky for us there are number of reasons why prions aren’t seen that commonly in the world. Firstly, its primary mode of transmission through different species is through ingestion. Food can be retracted from the market in case of an outbreak and food transmission is not as dangerous as airborne transmission of other diseases. Secondly, Human PrP only mishaps if it contains 129th amino acid as methionine. About 40% of human beings are now prion sensitive leaving 60% of the population immune to prions. This disease is mostly seen in tribal people who have the tradition of cannibalism, and in families which have had a history of prion diseases in their ancestry. The sporadic form of the disease is seen rarely. Prion problems are enigmatic as always as it is not known that the specific physicochemical nature of the agent is essentially a black box. It is also necessary to understand the exact mechanisms driving the transmissible protein states. The origin of different prion strains complicates the treatment. There is hence a need for more study to create adequate diagnostic tools to help create new therapy strategies to treat prion illnesses.