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Transmissible Spongiform Encephalopathies: A prion disease

by AhsanAli

Before starting today’s blog let’s start with what are prions and where did they came from. Basically, Prions are misfolded proteins with the ability to transmit their misfolded shape on to normal variants of the same protein. Prions are responsible for diseases like transmissible spongiform encephalopathies. Stanly Prusiner discovers prion to receive the Nobel prize in medicine in 1997. An entirely new genre of disease-causing agents but until now we have very limited information about them and we don’t even have any way to cure prion disease yet.
Evolutionary biologist Richard Dawkins mentions that it’s ok to eat human flesh if society allows you to do so. But it’s very important to know that is it really safe from a biological point of view.
In late 1950 in Papua New Guinea scientists found a remote place where a strange disease was spreading in the local Tribes Fore. The population of Fore was 12,000 but annually 300 died due to this unknown disease. Symptoms of this disease were a problem with walking, imbalance as they lost control
over their limbs even unable to do normal body functions and emotions. Initially, the disease was named Laughing illness or Kuru means Trembling and mostly women and children under the age of 8 were susceptible to it. The cause of the disease remains unknown for decades. But later found out that it is linked to
the bizarre funeral tradition Eat their Dead. As most women do this as it was suggested that women got dangerous spirit and the soul of the dead would kill that evil spirit and women allow their children to eat the brain of dead so the proteins of their dead relatives cause the illness those were not RNA or DNA but they increase in number over time in a way unknown to science and named as Prions, they are present in every animal including the human brain twisted incorrectly.

So if at the time of protein formation (prpc) their present a prion nearby it is turned into a dangerous molecule (PrPSc) as our body is unable to distinguish between them. The immune system shows no response against them.

Scientists believe that prion is normally removed by our body in a manner unknown to science. If they grow out of control then the person is doomed. They start infecting the brain cells first and the rest of the body later. Initially affecting the cerebellum part of the brain responsible for coordination and balancing of the body during movement. So impairment of mobility appears then lesions spread to the whole-brain resulting in sponge brain formation. As they were a separate population from the world it is believed that natural control of prion dismissal from body disrupted in a local due to genetic degeneration known as
Variant Creutzfeldt-Jakob disease similar to Kuru. It starts spreading in the whole fore tribe, but even when they stop eating dead disease kept on appearing as its incubation period for the disease was 27 years and symptoms appear 21 years. Later then it was observed the last case in the fore tribe was discovered in 2009.
Then it was observed that not only human flesh even an uncooked steak of mammal is a source of infectious prion. It causes transmissible spongiform encephalopathies. The reason is that prion can’t be killed. So if any animal found affected should be disposed of along with the equipment they use. Even in the case of humans, medical equipment like MRI machines was disposed of. As the disease was transmissible but 3rd world countries were not in a position to dispose of such costly equipment.
Simon Underdown from Oxford Brookes University believes Homo Neanderthalenis the closest to humans were wiped out due to cannibalistic diet. As it was discovered in 2009 that those who recently ate dead got immune to Kuru. The genome was extracted and inserted in rats than the rats were infected with all known prion and found no disease.
Today only one living organism on earth can resist prion disease Yeast. They help yeast to adopt a continuously adaptive environment. We are hopeful that humans will soon found a cure for prion disease. Presently, there is a chance of transmissible spongiform encephalopathies that may be turned into a new Plague to wipe out a large population as prion is also evolving.

Written by: Dr. Mansoor Altaf

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