Proteins That Kill: Will Prions Be the 21st Century AIDS?
by www.SixWise.com

Prions are mutated, slightly misshapen proteins. These agents are thought to be responsible for a number of closely related, currently incurable, rapid-spreading and fatal "prion diseases" known as transmissible spongiform encephalopathies (TSE).

Of these, the most talked about these days is bovine spongiform encephalopathy (BSE), or mad cow disease, which infects cows.

It is now known that this disease can be transferred to humans who eat meat or other tissue from BSE-infected cows. In humans, the disease is called Creutzfeldt Jakob disease (CJD), or new varient Creutzfeldt Jakob disease (nvCJD), when referring to the type related to BSE. In sheep, the disease is called "scrapie."

Why "nvCJD" is Of Great Concern

There is no cure for any of the TSE diseases, including the human forms, CJD and nvCJD. This infectious brain disease kills quickly once symptoms start, but seems to come out of nowhere because it can lie dormant for up to 40 years, according to the National Institute of Neurological Disorders and Stroke (NINDS).

The disease causes small holes to develop in the brain (making it look like a sponge), which causes changes in personality, loss of body function and finally death.

Prions Can't be Killed

Because prions are not actually alive, and contain no genetic information, they cannot be killed by any of the typical methods of heating, sterilizing, etc.

Normal prions occur naturally in the body and are harmless. But when a prion takes on a different folded shape than its normal counterparts, it becomes infectious. It's thought that once a prion becomes infectious, it alters other prions in a chain reaction.

The abnormal prions then clump together, which researchers believe may lead to neuron loss and brain damage.

"The New AIDS"

Because prions are so difficult to kill, and because they've been identified in the blood supply, some are calling prion diseases "the new AIDS."

There are several forms of CJD, with the most common (85 percent) being sporadic CJD, which appears in older people with no known risk factors. There's also hereditary CJD, which accounts for about 5 percent to 10 percent of cases, and acquired CJD, which is transmitted by exposure to infected brain or nervous system tissue, typically through a medical procedure.

The new variant variety differs in that it typically affects younger people and is thought to be caused by eating BSE-tainted meat. There have been about 150 confirmed deaths from nvCJD so far. It's thought that BSE was originally transmitted to cows because they were fed sheep meat infected with scrapie along with other cow parts that may have been infected.

No one knows for sure how many people have had, or have, a form of TSE, because it's now becoming clear that some cases of dementia and Alzheimer's disease may actually have been TSE. But because diagnosis would entail an autopsy, which most people don't have done on elderly relatives, the cases slip by undetected.

What Can be Done?

There is no test to detect prion-related diseases, no one knows for sure how long they can lie dormant before springing up, there is no treatment and there is no cure. Aside from humans, sheep and cattle, prion-related diseases have also been found in cats, mink, mule, elk and deer.

At this stage, the only real way to prevent prion diseases would be to take great care to stop including contaminated tissues, meat and more in animal feed, and stop feeding cow parts to other cows. Further, every cow should ideally be tested for the disease -- a test that reportedly costs about $30 a cow, making the ideal unlikely -- before it's allowed to be sold.

When, and if, that will ever happen is completely unknown. In the meantime, one way to ensure that your meat is prion-free would be to find a supplier of grass-fed beef. A grass-fed cow would not be exposed to prions via contaminated feed (if they are truly all grass-fed).

The U.S. Food and Drug Administration does maintain that the U.S. beef supply is safe to eat, however. "Consumers should feel very confident that the system of multiple firewalls maintained by Federal agencies protects them from possible exposure to BSE. In addition, we believe it is important for consumers to also understand that scientific research indicates that muscle meat is not a source of infectious prions," says the FDA.

Recommended Reading

How Many Insect Parts and Rodent Hairs are Allowed in Your Food?

The Six Most Feared but Least Likely Causes of Death

Sources

National Institute of Neurological Disorders and Stroke

Prion-Related Diseases

Madcow Opens Door to Grass-Fed Beef

U.S. Food and Drug Administration