(Mad Cow Disease)

Introduction

Mad Cow Disease or bovine spongiform encephalopathy (BSE) is certainly one of the most fascinating ailments in all of time, however, it is not a virus, as is often thought. Rather, it is the multiplication of prions (pree-ons) in the brain and the central nervous system.

 

There are different kinds of spongiform encephalopathy, given the name due to its sponge-like appearance under electron microscopes. One kind is Scrapie, found in sheep, another is Creutzfeldt-Jakob Disease (CJD) found in Humans, and BSE is found in cattle. Many other animals are known to be similarly effected

 

CJD works by slowly converting the proteins of the nervous system into inert or dysfunctional versions by rewrapping the strings of amino acids which make up the protein. When many many of the proteins in a particular area of the brain are converted, the function that that area performs will become crippled. Slowly, over a period of years, the disease spreads and eventually kills the victim.

Symptoms (Human CJD):

• Anxiety
• Withdrawal
• Fearfulness
• Insomnia
• Loss of memory

To lead us to an ultimate understanding of these horrifying conditions, we need to acquire a bit of background knowledge and history of them.

History:

The origins of the Disease most likely lie in a condition in sheep called Scrapie. For our purposes, Scrapie is basically the same thing as BSE. Scrapie has been recognized in the United Kingdom, particularly in Scotland, in sheep for over 200 years. Isolated to that species, Scrapie posed little threat to the meat supply of the UK, as sheep was not considered a food supply in that area.

 

The Jump to Cows:

As the beef industry in the United Kingdom took off, new ways to make the cattle grow larger and more profitable were being developed. One of these strategies was to feed the cows protein supplements to make up for the often meager diet fed to the animals. Offal, or the leftover parts of butchered animals, was added to the menu as one of these protein supplements. One of these leftover parts included the brains of sheep.

In the brains of an infected animal are infectious prions, which are able to transform normal working brain proteins into copies of the useless abnormal prion. If enough of these normal proteins are transformed, a system of the body may be rendered ineffective, or even destroyed.

 

How it's Done:

Proteins are constructed from strings of amino acids which wrap themselves a certain way in order to be recognized by the body. An abnormal protein (prion, in the case of BSE) wraps itself the wrong way and is not recognized. The prion then, instructs the other proteins to rewrap themselves the wrong way. An example below:

A prion from an infected sheep is consumed by a healthy cow. The prion, through the blood stream, makes its way to the brain. There, it comes in contact with healthy brain proteins and helps one of them to "rewrap" themselves. Both of these proteins then become inactive for their normal function. These two "rewraped" proteins come in contact with 2 more proteins. Now, we have four inactive, abnormal proteins. Now, each of these four proteins come in contact with 4 more normal proteins, rewrapping each of these as well. We now have 8 new abnormal proteins or prions. If we continue this out……. you can see what would happen.

These abnormal prions will travel all over the brain, infecting new areas and causing new disorders.

 

The Epidemic:

Farmers in the United Kingdom continued to feed their cattle the remains of infected sheep, unknowingly infecting the cattle with BSE. Then things started going wrong; cattle began to become very sick, literally heel over and die, all across the UK. The industry was in a state of panic: What could be killing all of these cows? In the meantime, remains of the cows killed by the disease were being fed to others in the herd, magnifying the epidemic. By 1993, the answer was clear. Banned was the practice of using offal in protein supplements. Unfortunately, over 160,000 cows in the UK had been identified with the disease. Over 50% of the herds were affected.

 

The Slaughter:

Enraged and terrified, the public demanded the complete elimination of cattle from the United Kingdom. Many millions of cattle were slaughtered in a relentless effort to eradicate the disease. However, in 1993, over a thousand new cases were being reported every week. From a purely logical point of view, the killing of all of these cattle made little sense. No solid evidence had yet been discovered to link BSE in cattle to its human counterpart, Creutzfeldt-Jakob Disease (CJD). The British government reassured the people that BSE posed absolutely no risk to humans, and was not linked to CJD.

 

The Evidence:

CJD occurs in many countries around the world, even in those where BSE does not exist. This is due to errors in the proteins in their initial wrapping. However, in late 1993, a startling 10 cases of CJD erupted within a short period of time. After conducting analysis of each of the cases, it was concluded that the disease did not occur on its own- a prion from an outside source was consumed. The most likely suspect at the time was beef that the victims had consumed as children.

 

Aftermath:

The Mad Cow Disease epidemic crippled the British beef industry. If it "goes under," 300,000 jobs are at risk, and it could cost Britain 30 billion dollars economically. Many in the country are paralyzed with fear of beef, even imports.

So What?

Though BSE has not yet been proven to be transmissible to humans, many are still concerned about consuming beef. If you live in the United States, you have nothing to worry about; no cases of Mad Cow Disease have ever been reported. If you are in Britain, you most likely don't need to worry. Cattle in the United Kingdom have been tested for BSE, and the infected were killed. Much of the beef in the country is now imported from the US or Denmark.

To Wrap it Up:

Mad Cow Disease is not a virus, it is a renegade protein (prion) that does not function properly. The prion assists normal proteins to rewrap and become a prion.

No proof has arisen to link BSE in cattle to CJD in humans, yet the transmission HAS taken place in cats. At this point, however, it does seem likely that BSE can and has jumped to the human population.