head tremors and a loss of coordination. It died a few months later on February 11, 1985,

while other cows began showing similar symptoms.

But it wasn't until September of that year when a government pathologist determined that

cow number 133 died from spongiform encephalopathy, later called bovine spongiform encephalopathy

(BSE) or, more commonly, mad cow disease.

And it would take several more years until scientists on the Spongiform Encephalopathy

Advisory Committee (SEAC) announced a possible link between the disease in cows and a similar

disease in humans (announcement made on March 20, 1996), sparking numerous efforts to curb

its spread, from banning British beef exports, to culling more than 4 million cows, to banning

blood donations.

While early predictions estimated the outbreak would kill thousands to tens of thousands

of people, there have only been 231 human fatalities worldwide, the majority within

the UK.

However, in 2013, a study was published where researchers tested over 32,000 appendices

from British people for the disease. And they worryingly found that 1 in every 2,000 people

in the UK is carrying the abnormal protein that causes the disease but are not showing

any symptoms. At least not yet.

Because an estimated 31,000 people are still carriers of the disease, preventative measures

like blood donation bans are still in place to avoid transmission. In the US, if you spent

more than 3 months in the UK from 1980 to 1996, you can't donate blood.

But as the pandemic rages on, blood shortages are dire. Hospitals are struggling to have

enough on hand. And since the 90s, new blood tests have been developed, and general cautions

in blood donations have advanced. So are these bans just overkill at this point, or are they

still necessary?

When BSE is transmitted to humans it's called variant Creutzfeldt-Jakob disease or vCJD.

This is just one of four major types of CJD, which are classified by how it is contracted.

In addition to variant CJD, there is sporadic CJD, the cause of which is unknown. However,

it is the most common, though still extremely rare, affecting 1 or 2 people per million

each year in the UK. Familial or inherited CJD occurs when someone inherits an abnormal

protein gene from their parent. And Iatrogenic CJD occurs accidentally in the medical setting.

One famous occurrence took place between 1958 and 1985 when thousands of children were injected

with human growth hormone collected from deceased donors who were unknowingly infected with

CJD.

CJD altogether is an extremely rare but fatal condition. It's caused by an abnormal, infectious

protein in the brain called a prion.

Prions are misfolded proteins with the ability to transmit their misfolded shape onto normal

variants of the same protein, inducing them to change their conformation as well, producing

a chain reaction that propagates the disease and generates new infectious material.

This is unique in the disease world. Before prions were discovered, it was believed that

all pathogens, like bacteria or viruses, had to contain nucleic acids to enable them to

reproduce - like DNA or RNA. The discovery of prions opened our eyes to a totally new

mechanism of disease.

And it is a particularly devastating one. Their misfolded shape creates brain damage

which quickly worsens over time.

Proteins are a very important part of our body's chemistry and are responsible for

the structure, function, and regulation of our tissues and organs.

They are large molecules made up of hundreds to thousands of organic compounds called amino

acids, which are attached in long chains or strings. These strings then fold into a 3D

shape. This “protein folding” is key, as each protein forms a specific shape that

allows it to perform its specific function. But if a mistake occurs, they can misfold,

or fold incorrectly, which is how an abnormal prion occurs.

There are many diseases caused by misfolded proteins. These can lead to a loss of function,

like in cystic fibrosis or Tay-Sachs disease, where one type of protein is misfolded and

therefore can't do its job. They can also stick together and cause clumps or plaques

which disrupt cell function. This is what scientists think may be the cause of neurological

disorders like Alzheimer's and Parkinson's. The other way prions devastate the brain is

by creating holes.

The infectious prion responsible for CJD converts normal proteins into an abnormal state. As

they build up, they cause brain cells to die, which releases more prions, and so on. In

areas where brain cells are killed, holes are created that make the brain sponge-like.

This type of brain damage causes symptoms similar to other neurological disorders, like

Dementia. In variant CJD, typically psychological symptoms that affect a person's behavior

and personality develop first.

In a few months, neurological symptoms develop, such as problems with coordination,

slurred speech, numbness, dizziness, and vision problems.

Over time, symptoms worsen until the patient is bedridden, completely unaware of their

surroundings, and can't communicate. The disease always progresses to death.

It took some years of research to nail down just how BSE spread from cow to cow and from

cow to humans. Eventually, they identified the source as their food, in both cases.

At the time, cows were often fed the remains of other cows. So, if they ate infected meat,

they too became infected. This led to a spread of BSE between cows, eventually reaching a

peak infection rate in 1993 of 0.3% of the UK national herd. The answer: ban the feeding

of meat-and-bone mix to farm animals.

Likewise, humans who ate beef containing infected nerve tissue contracted vCJD. While, initially,

it was thought that humans weren't affected by the disease, once it was made clear that

they were, bans were quickly placed on British beef exports, cattle over a certain age were

banned from the food chain, and at-risk cows were culled.

But eating infected beef isn't the only way humans can get vCJD. And this is where

the blood bans come in. There were four cases in the UK where a patient contracted vCJD

after receiving a blood transfusion.

Quickly, blood donation bans were put in place in countries like the U.S., Canada, Australia,

where people who have spent several months in the UK in the 80s and 90s are not allowed

to donate blood.

This seems like a broad stroke to ban millions of possible donors from just 4 instances of

blood transmission. But, for a long time, it's been necessary, because it's difficult

to know for sure if someone has vCJD. There is no blood test that can simply tell you

if you have it. Typically, a diagnosis is made by considering the patient's symptoms

and through neurological tests like MRI, which could show abnormalities typical of vCJD.

But even then, its not conclusive. The only way to confirm a diagnosis is by analyzing

the patient's brain tissue, which can only be done after they have died.

So scientists are aiming their sights here: if there was a way to test for vCJD in living

patients, then the ban could, in theory, be permanently lifted.

Because prion proteins are primarily found in the brain, they are hard to detect in blood.

So, researchers have developed a method to amplify the prions in blood samples called

“protein misfolding cyclic amplification” or PMCA.

It works by taking advantage of the infectious prions' natural tendency to convert normal

proteins into an abnormal state. They did this by combining healthy proteins with a

small amount of infectious prions and agitating the mixture with sound waves. The sound waves

broke up the chunks of infectious prions, helping them to meet and infect normal proteins.

Studies have shown that this method can accurately detect vCJD in human blood samples and even

distinguish it from other types of neurological disorders, including sporadic CJD. In a 2016

study, it was found to correctly identify those with or without the disease 100% of

the time.

It can even detect it in patients who aren't showing any symptoms. In another study published

in 2016, their test detected vCJD prions in two patients 1.3 and 2.6 years before they

began showing any signs of the disease.

While these results are extremely promising, it is still early days. A clinically available

blood test has yet to be released.

Nevertheless, some scientists think its time to rethink the bans on blood donations, especially

with the implementation of safety measures like leukoreduction, a process which removes

white blood cells from blood, since white blood cells sometimes carry pathogens. Methods

like this have already helped to change the donation regulations in many countries around

those who are at high risk of sexually transmitted diseases like HIV and AIDS.

Increasing the number of potential donors is even more of a priority with the current

blood shortages caused by the Covid-19 pandemic.

Since the pandemic began, there have been alarming shortages of blood supplies. For

one American blood center, 31% of their locations have a one-day supply or less.

Luckily, changes have begun. In 2019, the Irish Blood Transfusion Service lifted their

ban, enabling some 10,000 individuals to now donate blood. And in 2020, the FDA lifted

their ban on US military veterans who served in Europe, now allowing 4.4 million more people

to donate.

With more testing and trials, soon this catch-all ban should be lifted in the US, saving hundreds

of thousands of lives with much needed blood.

How we treat our farm animals invariably affects our own lives. Mad cow disease, swine flu,

avian flu - many diseases of the modern age spread to us from livestock, and many diseases

like this happen due to the poor and overcrowded conditions in which we keep these animals.

Keeping the animals healthy, will in turn, keep us healthy - along with it being simply

the right thing to do.

Ending the practice of feeding COWS to OTHER COWS was a solid step in the right direction.

But there are still a lot of other bad practices, like pumping them full of antibiotics, that

need to come to an end.

Helping in this endeavor are new technologies being rolled out around the world, like this

silly robot named Astronaut, which is a fully automated milking system. It lets the cows

decide when they want to get milked, with no human input required, along with cleaning

the utter before the milking process. Being milked more often means the cows get sick

less often, they get fewer infections, and thus need fewer antibiotics. To learn more

about this elegant solution you should watch Milking Robots For Healthier Cows on CuriosityStream,

a part of the European Inventor Awards series. All episodes in the series are overviews of

cutting edge technology that is working to solve our most complicated problems.

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