Mad Cow Term Paper
- Length: 8 pages
- Subject: Disease
- Type: Term Paper
- Paper: #34318618
Excerpt from Term Paper :
80s and the 90s, an unknown but virulent cattle disease, called "Mad Cow," destroyed 180,000 livestock in the United Kingdom and some other European countries and plunged other major cattle-producing nations - including the United States - into global panic (Freudenrich 2004). Health experts assured the public that humans were not prone to it. Nonetheless, its symptoms resemble those of an already existing and similarly deadly human nervous condition called Creutzfeldt-Jakob Disease (CJD), believed to afflict only those 50 years old and older. CJD was then linked to Mad Cow, but believed to be limited to the older population. In the mid 90s, however, several British young people, died of a new variety of disease with similar symptoms to both Mad Cow's and CJD's, this time plaguing the young (nvCJD). In all those troubled years, contaminated British cattle were exported to as many as countries, including the U.S.A., as animal products and by-products (University of Wisconsin Board of Regents 2001).
The Mad Cow Disease is bovine spongiform encephalopathy or BSE is a fatal brain disorder in cattle and caused by a still-unknown agent (Freudenrich). When activated, this agent kills brain cells and leaves large spongy holes and large clumps of abnormal prion proteins or plaques, similar to those in Alzheimer's. The disease runs its course and kills the infected host in less than a year. The BSE agent can spread among species, which ingest the brain or other nervous tissue of infected foods or food by-products. Once taken in, the infectious agent can remain dormant in the body of the infected host up to 10 or 15 years until it is activated (Freudenrich). Only then will the symptoms manifest and control measures can be taken. These symptoms are weight loss, abnormal behavior (skittishness), paralysis and death (Freudenrich).
Only a few things are known about BSE. It is smaller than a virus and requires much higher temperatures than cooking or sterilizing in order to kill it. Ordinary chemical disinfectants are not effective against it and it appears to have no genetic information (Freudenrich), like infectious nucleic acids do, that can provide the clue to its control.
A similar disease among sheep, called scrapie, in the 1980s was blamed for BSE. Cattle feed was then made from ground meat and bone meal by-products from sheep. The processing method was later on changed, and this could have allowed scrapie to survive and contaminate cattle that fed on them, resulting in the emergence of BSE. Although neither scrapie nor BSE can affect people, their unknowingly ingesting the nervous tissues of infected cows through the food supply developed into CJD in the elderly and nvCJD in younger people.
The disease spread to cattle in other countries through infected animal feed UK exported to them within that decade. These countries in Europe alone included Belgium, Canada, the Czech Republic, Denmark, France, Germany, Greece, Ireland, Italy, Luxembourg, Liechtenstein, the Netherlands, Portugal, Spain and Switzerland (Lohn), which were reported to have at least one infected cow each. The UK also supplied animal feed to South Africa and non-European countries at that time, extending the reach Mad Cow beyond Europe and making it a global health scare.
The British health minister's shattering public admission in 1996 that (British) beef infected with Mad Cow probably caused the new variety of CJD (nvCJD) destroyed the sales of British beef around the world (Lohn). The admission decidedly gave economic and political advantage to the U.S., as a world leading meat exporting nation, as long as the U.S. government could assure the market that its cattle were reasonably Mad Cow-free. As of December 2003, there were 153 reported cases in the world, 149 of whom were in the UK and the rest, acquiring the disease while in the UK.
Biochemist Stanley Prusiner suggested that Mad cow, scrapie and nvCJD are forms of transmissible spongiform encephalopathes or TSEs, which develop from abnormal proteins, called prions (University of Wisconsin Board of Regents). His view soon gained popular acceptance. Prions are not nucleic acids, which possess DNA and RNA that can reveal their life processes and agenda. Normal proteins are harmless (Lohn) but researchers are of the opinion that prions induce normal ones to imitate them. These prions' lysosomes grow and crowd the nerve cell, which later dies (Freudenrich). The death of many nerve cells leads to brain dysfunction and, eventually, to the death of the host. One gets nvCJD by consuming the products and by-products of even small parts of infected cattle, such as the brain, spinal cord, the gut or bone marrow. These small parts are added to candies, cosmetics, shampoo, gelatin, yogurt, ice cream, mints, gummy candies, margarine, lotions and bone meal for gardening (Lohn).
UK reports also listed other animals as having been infected by TSEs and these included domestic cats, mice, hamsters, goats, mink, monkeys, pigs, cats and some exotic species of the cat family. More than 80 domestic cats in the UK were reported afflicted with the cat or feline version of Mad Cow after being fed with pet food made from animals with Mad Cow or similar diseases (Lohn). Think about how one infected domestic cat can pass the disease on to other domestic cats and animals at home and in the neighborhood.
British neurologist John Collinge experimented on mice, which were found infected with prions, but did not display the symptoms of the disease. His findings called attention to the danger posed by "silent carriers" of TSEs (University of Wisconsin Board of Regents) that have yet to develop their own species of the disease.
Control measures were reportedly to have been promptly taken. In 1988, the British government banned the use or ruminants (cattle, sheep and goats) and ruminant by-products I animal feed. It also surveyed BSE-infected cattle and the population for nvCJD cases. Overall steps brought the incidence of BSE down by 1992. Other European countries have instituted their own countermeasures.
The U.S. Department of Agriculture prohibited the importation of live ruminants and ruminant products, such as meat, feed and their by-products, from Europe (Freudenrich). The USDA tested cattle showing abnormal behavior, suggestive of BSE and other signs of neurological diseases. The U.S. Food and Drug Administration (FDA) prohibited the use of mammalian proteins in developing animal feeds for ruminants. The FDA also advised pharmaceutical companies not to use animal tissues coming from countries with BSE in developing vaccines and other drugs. It also asked blood centers to exclude blood donors who spent six or more consecutive months in the UK between 1980 and 1986. Besides regularly monitoring the U.S. population for signs of nvCJD, the Centers for Disease Control (CDC) also recommended that travelers to Europe avoid eating beef and beef products altogether. All three government agencies have been monitoring the meat supply and imports and have given the assurance that the danger is low at this time.
But there are stinging realities to take serious stock of. A common American household was a regular consumer of beef products between 1980 and 1990 when the plagued ravaged British cattle and the infection circulated in the Continents. Candies, mints, yogurt, ice cream and gelatin could have taken hidden but infected cow parts from manufacturers to supermarkets to the household. Leftovers and feeds were also given to pets and other ruminants and these animals could have passed on the prions to one another. Considering the two-to-eight-year incubation period of inactive prions, the magnitude of the contagion would be unimaginable by the time the symptoms are detected and any control measure is taken. By radical calculation, the disease is probably here but not yet detected. Or it is here but leaders are not so anxious as to look for it, much less to report it. The fact is that the U.S. government is not as stringent on its own cattle as it is on imported cattle.
For one thing, the rules that ban imported animal feed have loopholes (Lohn). In 1997, the USFDA banned the feeding of ruminants (cows, sheep, goats and deer) to other ruminants (which is how Mad Cow is said to spread.) But Deputy Director. Peter Lurie of the Public Citizens' Health Research Group in Washington DC notes that there have been exemptions to the FDA rules. Some restaurants and other institutions still turn out leftovers made into cattle beef even if they contain beef. That means that cows are still fed to cows, according to Dr. Lurie (as quoted in Lohn). Or these ruminants still ingest the prions from ruminants of other species, such as pigs, chickens and domestic cats when they eat food processed from dead ruminants, such as sheep, deer and the elk. These ruminants can be slaughtered, processed and fed back to cows (Lohn). It has also been reported that many feed mills and rendering plants do not wash their vats in between feedings of ruminants and non-ruminants, according to New Jersey-based veterinarian Linda Detwiler. Feedings in other mills are not even labeled, according to her.
Another thing is that…