The human variant of Creutzfeldt-Jakob disease (vCJD) - spongy brain degeneration is the first infection in the history of medicine that is transmitted without germs such as viruses, bacteria, fungi or zoonotic parasites. They infect the brain most likely degenerate microparticles of animal protein called prions. They come mainly from beef protein - from cows with spongiform encephalitis (with BSE). The disease in animals is known as mad cow disease.
Prions - what do we know about them?
Prions are microparticles of animal protein. They have their benign form marked with the -cPrP symbol present in all healthy cells and degenerated in the body of the cow - a pathogenic type of scPrP.
The pathogenic form of prions destroys the cells of the nervous system, especially the brain.
Prions are resistant to acids, alkalis, high temperature, UV radiation, which distinguishes them from other proteins. Entering pathogenic prions into a healthy organism does not cause a defensive reaction, which means that we get asymptomatic. Unfortunately, there is no cure to eliminate pathogenic prions from the body.
Infection of the body with prions
Prions can be infected by eating beef containing the pathogenic type of these proteins. Apart from beef protein, the prion carrier is also another animal tissue collagen - a protein-sugar molecule, known and commonly used as gelatin. The infection can also be caused by body fluids of a person infected with prions (in the case of wounds, during blood transfusions, organ transplants). Transmission of prions may be hereditary.
More about prions and the threat to their health
Apart from beef protein, the prion carrier is also another animal tissue collagen - a protein-sugar molecule, known and commonly used as gelatin. In the digestive tract, collagen is broken down into sugars and amino acids. Amino acids are protein building blocks, which may contain prions and incorporate into human tissue.
Prions in proteins of transplanted tissues?
The proof for the presence of prions in animal and human tissues and their infectivity for humans is the disease after brain transplants. It has been documented that a number of people whose post-operative brain losses were supplemented with grafts from a tissue bank - after some time Creutzfeldt-Jakob! - Why? The only reason could be that the transplanted parts of the human dura - built almost entirely of collagen - were infected with prions. Hence, in many countries a ban on feeding cows and other animals with bone meal, which in a large percentage is made up of collagen fibers, appeared.
What is the mechanism of the disease?
Pathogenic prion type scPrP does not reproduce in the body like bacteria or viruses. By encountering proteins with the correct structure, they change their spatial structure that they become pathogenic. These "damaged" protein microparticles affect the brain cell metabolism, that according to the "domino principle" - these become similar to the degenerated structure of cow's brains and die. As a result of the progressive destruction of brain nerve cells, "similar holes" are found in the brain of fallen animals and dead people. That is why the name of the disease is spongy brain degeneration.
The time from infection to the first symptoms of Creutzfeldt-Jakob disease?
In humans, the first symptoms of spongy brain degeneration usually appear several years after infection. It can be up to 20 years, but sometimes the incubation period lasts only a few months.
