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Saturday, August 05, 2006

Mad-Cow Disease: a summary of what is known about it now.

By Nate Leskovic (nleskovic@hotmail.com)

Though the first American case of Bovine Spongiform Encephalopathy (BSE) -- better known as Mad Cow Disease -- was discovered in December 2003, sensationalism and general concern about the disease have been basically non-existent since. Is this comfort justified? What role has the government and media played in assuaging fears? Is there cause to worry about a future epidemic of new variant Creutzfeldt-Jakob disease (nvCJD), the human form of BSE? Though in no way do I wish to incite panic, I believe that Mad Cow will make the headlines again.

Continued...to "Read More" click link below

CONTINUED:

BSE is caused by a relatively new biological discovery, the prion. In the Ultimate Fighting Championship of semi-living organisms, prions have the potential to kick the ass of the virus. In 1997, Stanley Prusiner, M.D., a professor of neurology at the University of California, San Francisco School of Medicine, won the Nobel Prize for his discovery of prions, “tiny protein molecules that seem to cause a variety of slow acting and inevitably fatal diseases in animals and humans.” The name is an acronym for proteinaceous infectious particles. The effect of the disease, in cows as well as humans, is the disintegration of brain tissue into a spongy mass.

The prion is not a bacteria or a virus, and it has no DNA or RNA. In an organism, it resides in the brain, spinal, and nerve tissue. The prion has no means of replicating itself, but when it comes into contact with proteins in the brain it changes them, causing the disease. Because the prion is not an organism, it cannot be destroyed by normal disinfection, radiation, UV rays, or incineration. It is for this reason that the prion is so frightening.

Prions are transmitted in a multitude of ways, but currently the most common way is through food. They can move from o­ne organism to another by ingestion. This frequently happens because of rendering, the process in which dead animals, as well as the leftover portions of slaughtered animals, are ground into a protein mix to feed other animals. Cows that eat infected sheep (Mad Cow is called Scrappies [scrapie --pseudolus] in sheep) can develop BSE. Cows are sometimes fed to other cows, and transmit BSE this way. Passing prions between farm animals can eventually result in the infection of humans -- when they eat infected cows. From a May 2004 Alternet piece:

“If you inject cows with rBGH [recombinant bovine growth hormone, the genetically engineered drug designed to increase a cow’s milk production], you will have to feed them fat and protein supplements,’ because rBGH takes a heavy toll as it hikes milk production. Likely to be used, he said, would be ‘the cheapest form’ of fat and protein: slaughterhouse waste. And this waste, the researcher said, would inevitably include parts of animals infected with mad cow disease -- and the disease would be passed o­n. The use of slaughterhouse waste was how mad cow disease had spread in Great Britain and elsewhere in Europe in the 1980s.”

In response to the 2003 BSE case in Washington State, the USDA implemented a ban o­n “downer” cows, or those who are unable to walk when slaughtered. It was originally thought that the cow was a downer, and that these unfortunate types were most likely to have the disease. However, it was later determined that the cow was able to walk to its execution. Essentially, this ban o­nly eliminates a portion of potentially infected cows from the food supply.

Furthermore, there is no reason to believe that downers are more likely to have BSE. A cow may have the disease and not show any symptoms, for it is known that there is a gestation period. In cows this is usually 2-8 years, though sometimes up to 10, and in humans it is usually around 5-10, though sometimes more. The earliest age a laboratory has detected BSE in a cow is around 20 months, hence the gestation period. The prions that cause the disease cannot be detected at all.

Because the symptoms are so similar, some Alzheimer’s patients actually have nvCJD and have been misdiagnosed. Due to this and the gestation period, there could be hundreds or thousands of Americans with nvCJD right now. Though this may be unlikely, chances raise the longer rendering processes continue. If nothing else, there are surely many farm animals currently infected. From PETA’s website:

“Because the infected cow was raised for dairy production, she had lived long enough to show symptoms of the disease. Most cows are killed before they turn 2 years old, chickens at 6 to 7 weeks, and pigs and turkeys before they’re 6 months old, long before they could become symptomatic; no o­ne would know whether they were infected with spongy brain disease…”

It is still legal to feed sheep and cows to pigs and chickens; feeding pigs and chickens to o­ne another and to cows is okay too. These practices have been banned in Europe. Cow and sheep blood is still fed to cows and sheep, as well as chickens, turkeys, and other farm animals. Baby cows are often fed “milk replacer,” (don’t want to waste that precious cow milk o­n calves) which is actually made from cattle blood. It is illegal for humans to donate blood in the U.S. if they have spent three or more months in the U.K. due to the mad cow outbreak, however cows are still allowed to eat other cows’ blood.

Feeding sheep and cows to other cows was not prohibited in the U.S. and Canada until 1997, and the U.S. government said as recently as 2001 there was widespread violation of this regulation. In 2002, the U.S. General Accounting Office released a report o­n Mad Cow Disease:

“BSE may be silently incubating somewhere in the United States. If that is the case, then FDA’s failure to enforce the feed ban may already have placed U.S. herds and, in turn, the human food supply at risk. FDA has no clear enforcement strategy for dealing with firms that do not obey the feed ban.... Moreover, FDA has been using inaccurate, incomplete, and unreliable data to track and oversee feed ban compliance.”

Because of the relatively new discovery of prions, much remains unknown. Exactly which animals are susceptible, besides sheep, cows, and humans, is not known. There have been cases of Mad Mink Disease, and spongy brains have been found in cats, dogs, deer, and elk. Hunters use the term Chronic Wasting Disease in diagnosing animals they kill that fit this description as well. It is not known whether any other animals can transmit prions to humans other than cows. There has, however, been some inconclusive evidence that hunters have contracted nvCJD from eating infected deer. Again, while perhaps not widespread, surely the issue deserves attention.

The USDA and meat industry state that prions are not found in the muscle (the part people eat) of cows. They conclude that since brain and spinal cords are usually not eaten, humans face little risk. In a June 2004 MSNBC article:

“When supermarkets found meat from the lone infected Holstein had made it into shoppers’ carts, officials quickly pointed to evidence that animal muscle doesn’t contain the deformed prions believed to cause mad cow’s equivalent illness, variant Creutzfeldt-Jakob disease, in humans.”

Research has shown this is not always the case. Even the USDA’s web site states: “Epidemiological and case studies have not revealed a common risk factor among the cases of vCJD. According to the SEAC [the U.K.’s Spongiform Encephalopathy Advisory Committee], all victims were reported to have eaten beef or beef products in the last 10 years, but none had knowingly eaten brain material.”

Nerve tissue, in which prions are often found, is located throughout muscle. From PETA: “Stanley Prusiner, the scientist who won the Nobel Prize in Medicine for his discovery of prions, describes the levels of prions in muscle as ‘quite high.’ Follow-up studies in Germany, published May 2003, confirm Prusiner’s findings, and in 2003, the New England Journal of Medicine published research indicating that deadly prions were found in eight of the 32 muscle samples of human CJD victims. The authors declare that the prions were ‘prevalent in skeletal muscle tissue.’”

Even if prions were o­nly located in brain and spinal tissue, this would still not eliminate transmission. During the process of slicing cows into various “cuts,” it is not uncommon for mistakes to be made, resulting in the packaging of brain and spinal tissue. Think, Sinclair’s The Jungle. Furthermore, it is known that during the “stunning” of cows before slaughter, often by driving a metal bolt through the skull, pieces of brain can enter the bloodstream and make their way into the rest of the body. In a December 2003 Green Party statement:

“The first myth: U.S. beef is safe because brain and spinal cord tissue (which are said to harbor mad cow) are removed before processing. The claim is odd to anyone who has ever seen a T-bone steak, which includes a section of the spinal cord that can easily contaminate meat during butchering. U.S. Department of Agriculture reports reveal that as much as 35% of beef, hot dogs and sausage samples taken from advanced meat and bone separation machinery are contaminated with ‘unacceptable nervous tissues’ that may harbor the contaminants that cause Mad Cow Disease.”

The U.S. government defends its testing for BSE. The USDA tested around 150,000 cows in 2004. This is out of some 45 million slaughtered, or .3 percent. There are around 100 million total cattle, which makes those that are tested o­nly .15 percent. There were no tests o­n the more than 10 billion other farm animals. In a March 2004 Alternet piece: “...experts concluded that the reason the USDA has found o­nly o­ne case of Mad Cow disease is that it has not looked very hard…The panel chairman said that USDA might find “a case a month” of Mad Cow if it was doing enough testing.”

Also troubling, currently the USDA does not allow private testing of cattle. A December 2004 article o­n MSNBC states, “The more time passes without a new case, the more consumer confidence in the meat supply grows.”

But a slowly developing problem may be slipping by with the relatively small number of tests. Over 40 countries currently ban imports of U.S. cows. If they have reason to fear American farming, does that not give Americans reason as well?

Perhaps this is the true reason for the lack of apprehension regarding American cows. The cattle industry is worth more than $30 billion. According to a March 2005 A.P. article, meatpackers have lost more than $1.7 billion since the ban o­n Canadian cattle began. Recently, the administration decided to allow the resumption of imports, blocked by a temporary court injunction and voted down by the Senate, showing a potential bias in favor of business interest over safety. The same article illustrates ways the press has contributed to easing concern:

“‘They’ve got mad cow disease,’ said Sen. Kent Conrad, D-N.D. ‘Now the question is, should we run the risk of opening our border to livestock imports from Canada, when the evidence demonstrates clearly they’re not enforcing their regulations to reduce the risk to them and to us?’”

When the first case of Mad Cow Disease was discovered in December 2003, President Bush and his administration were quick to declare that American cows were safe. Bush proudly ate cow for Christmas dinner. Unfortunately, the herd of 80 that the infected animal came from -- which may also have been exposed -- was never completely accounted for. O­nly o­ne-third of them were ever found. The rest, obviously, entered the food supply.
SOURCE:
the Student Underground - Mad-Cow Disease, by Nate Leskovic (nleskovic@hotmail.com)

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