Difference Between Virus and Prion
Our understanding of pathogens causing Infectious diseases is limited to protein made virus and bacteria. However, Stanley Prusiner has discovered one more species of pathogens called prions. These are single protein pathogens which have the capability to create havoc on brain cells. These show many similarities with viruses and are different from them in many aspects as well. As known, viruses are an intermediate link between living and non living things. Similarly, prions are non living things too. Like virus, they also need living cells to grown and reproduce.
As known, viruses are made of lipids, protein, nucleic acids namely RNA and DNA. Once, viruses have found their way to the cells of any living being, these nucleic acids help them to reproduce by feeding on the building material of the cells and host’s body. These acids are encapsulated in a protective shield known as capsid. Before finding an appropriate host, the capsid protects the nucleic acid of extracellular virus. Once after invading, the capsid gets dissolved and reveals the DNA to the host cells to reproduce more intercellular viruses.
Prions do not have nucleic acid in their cell structure. These are said to cause only neurodegenerative or brain diseases such as transmissible spongiform encephalopathy, Mad Cow Disease, Scrapie (found in sheep and goat), and Creutz-Jakob disease. They are made of protein commonly found in mammal animals and birds. Though, the protein is in abnormal form and when enters human body, it develops faster and causes brain infection.
Most of the times, the protein is ingested as a result of defense mechanism of body but the mutation of the protein containing gene cause them to transform into harmful protein pathogens. As soon as prions reach brain cells, they cause mutation of normal proteins which results in brain infections. During X-ray screening, the infection is appeared as holes in the brain. The only way to get rid of the infection is incineration.