Roxanne Khamsi For years, experts have feared that thousands of people are unknowingly carrying and transmitting the human form of mad cow disease: new-variant Creutzfeldt-Jakob disease (vCJD). Now a blood test could help to ease their worries, or confirm their worst nightmare. Researchers have succeeded in reliably detecting the malformed proteins that cause vCJD in blood samples taken from hamsters. Their test takes only a few days to complete. If the procedure works as well in humans, it could be used to check stocks in blood banks. At the moment there is no such screening process; two of the people who have died of vCJD in Britain are thought to have picked up the disease from transfusions. If improved, the test might also be used to screen animals for the disease before they enter the food chain. The rare disease is thought to be caused by the formation of abnormal proteins in the brain known as prions. These misshapen proteins apparently multiply by changing the conformation of normal proteins that they come into contact with, eventually leading to a fatal neurodegenerative illness. ©2005 Nature Publishing Group

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By Marc Kaufman, Washington Post Staff Writer New tests have confirmed that a Texas animal that federal officials earlier declared to be free of mad cow disease did have the brain-wasting ailment, the U.S. Agriculture Department announced yesterday. The definitive testing, done in England over the past two weeks, showed that the ailing animal, first flagged as suspicious in November, was infected with mad cow disease. The animal was retested after the USDA's inspector general requested the additional check because of continuing concerns about the sample dismissed by the agency. USDA Secretary Mike Johanns said that officials are just now trying to learn more about the origins of the animal, but that there is no indication that it was imported, as was the only other animal to test positive for the disease in the United States. That would make the newly identified animal the first born in this country found to have mad cow disease. Johanns sought yesterday to assure consumers that U.S. beef is safe, and that any suspect beef would have been kept off supermarket shelves. © 2005 The Washington Post Company

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Nicola Jones The ongoing threat of prion disease was hashed over by a UK government advisory committee this week. They heard evidence from recent studies of these deformed proteins, which cause mad cow disease and its human version, new-variant Creutzfeldt-Jakob disease (vCJD). The committee will use the information to help formulate advice for UK food agencies and blood banks on whether they should take further measures against prion infections. "We have become more rather than less anxious," says Marc Turner from the Scottish National Blood Transfusion Service, Edinburgh. Two people are thought to have died from vCJD after being infected by blood transfusions. There are no documented cases of anyone getting prion disease through surgery, but there remains a theoretical risk. However, several commercial products are in the pipeline to keep surgical steel free of prions and at least one is expected to be on the market by the end of 2005 (see 'Enzyme washing power cleans up rogue prions' ). British blood banks have already taken action to reduce prion content in blood products by, for example, removing white blood cells. They may also consider prion filtering, although this would be very expensive, and they could exclude donors of certain ages, although this would dramatically reduce blood supplies. "We are in a position of trading risks," says Turner. ©2005 Nature Publishing Group

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Roxanne Khamsi One assumption lies at the root of efforts to keep the meat we eat safe from mad cow disease: that tissues beyond an animal's brain, spinal cord and immune system are free of the prions that cause the disease. A disturbing study now shows that assumption to be false. Researchers have found that if an animal falls ill with another infection, its immune response can carry large numbers of prions to organs throughout its body. "The rules no longer apply," warns pathologist Adriano Aguzzi at Zurich University Hospital, Switzerland, who led the research. Mad cow disease, more correctly known as bovine spongiform encephalopathy (BSE), is believed to be caused by rogue proteins called prions. When these prions enter the human food chain, they can cause the equivalent disease in humans, called new-variant Creutzfeldt-Jakob disease (vCJD). ©2005 Nature Publishing Group

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Canada has found its third cow infected with BSE - bringing the number of native mad cows detected in North America to four. All of the infected cows detected so far were born in Alberta, Canada, where a clinical case of BSE was found in an imported British cow in 1993. This raises the question of whether the infection might have been limited to the province by chance, or whether other regions of the continent are just not looking hard enough to find infected cattle. In particular, the US surveillance programme has come under criticism. The most recently discovered infected cow was born in March 1998 - seven months after feeding beef remains to cattle was banned. The Canadian Food Inspection Agency (CFIA) says it was probably infected by feed made just before the ban. It was detected as part of Canada's surveillance programme which, like the one in the US, focuses on "high risk" cattle, those found dead or "downers" unable to stand. Experience in Europe has shown that these cattle are much more likely to have BSE than apparently healthy ones. The programme - which discovered the country's first case in May 2003 - found another Alberta-born mad cow in December 2004, this one born just before the 1997 feed ban. The sole case found so far in the US, in December 2003, was a downer born and probably infected in Alberta. © Copyright Reed Business Information Ltd.

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By ROB GILLIES, THE ASSOCIATED PRESS TORONTO -- U.S. agriculture officials reaffirmed their support for lifting the ban on Canadian beef despite the discovery of a second case of mad cow disease in Canada, expressing confidence that public health measures will protect American livestock and consumers. Canada's Food Inspection Agency said yesterday that an older dairy cow from the province of Alberta has tested positive for bovine spongiform encephalopathy, or mad cow disease. The results confirmed preliminary tests released last week. Canada suspects the cow became infected through contaminated animal feed. The cow was born in 1996, before a 1997 ban on certain types of feed, the agency said. It did not enter the human food or animal feed supply and posed no risk to the public, the agency said. The disease attacks an animal's nervous system. Food contaminated with the prions that cause it can afflict people with usually fatal variant Creutzfeldt-Jakob disease. ©1996-2004 Seattle Post-Intelligencer

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Helen Pearson The infectious proteins called prions that cause the human form of mad cow disease may hitch into the body on the back of another meat protein, US researchers have shown. The finding may help to explain how the rogue prions jump between species. Disease-causing prions are thought to have passed into people when they ate beef from infected cattle, triggering the brain wasting condition called new-variant Creutzfeldt-Jakob disease, or vCJD. But researchers have not been sure exactly how prions enter the body. To find out, Neena Singh and her team at Case Western Reserve University in Cleveland, Ohio, mimicked the process of eating and digesting infected meat. They mashed up brain tissue that contained prions from patients who had a form of Creutzfeldt-Jakob disease. They then exposed it to a range of harsh digestive enzymes from the mouth, stomach and intestine, which normally break proteins into pieces. Prions, which are known to be enormously tough, escape this attack almost unscathed, they showed, as does a second type of protein called ferritin, which stores iron and is abundant in meat. The two proteins seem to stick together, they report in the Journal of Neuroscience1. ©2004 Nature Publishing Group

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Jim Giles People with genes thought to protect against variant Creutzfeldt-Jakob disease (vCJD) may still be at risk of developing some strains of the illness, animal studies suggest. All of the 146 British people who have died from vCJD, which is thought to be caused by eating meat infected with the prion protein that causes mad cow disease, have a genetic variation known as MM. This led some researchers to hope that people with different variants, who make up 60% of the population, may be protected from the disease. But mice with such supposedly protective genes still seem to be susceptible to infection with the rogue protein, report John Collinge and colleagues at University College London in a paper published online by Science1. Researchers are cautious about the study's implications for humans, but say that it adds weight to the possibility that tainted beef could have infected more people than was originally thought. "In future we might see different types of CJD," predicts Markus Glatzel, who studies the disease at the University of Zurich in Switzerland. "This is a very important study." ©2004 Nature Publishing Group

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Eighteen years after BSE first emerged in the UK, we still have little idea how to treat people who have contracted the human version, variant Creutzfeldt-Jakob Disease (vCJD). An investigation by New Scientist has revealed that the relatives of people with vCJD are frustrated by the slow progress being made to find new treatments. Time and effort are being wasted researching drugs that simply do not work, they say, while other, radical, treatments are not being made readily available. But while researchers privately disagree over which approaches show most promise, they say there is now a united effort to find a drug best able to save lives. Later this month, the UK government's Medical Research Council will officially launch a trial of potential treatments, after four years of argument over which to test. Called the "PRION-1" trial it will focus on quinacrine, an anti-malarial drug that showed early promise in treating various forms of CJD. The National Prion Disease Clinic at St Mary's Hospital in London has already given the drug to around 20 patients, but the results are not yet in. © Copyright Reed Business Information Ltd.

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Test-tube 'prions' could advance study of mad cow disease David Perlman, Chronicle Science Editor Scientists at UCSF have created synthetic prions -- tiny protein particles -- and shown they can cause brain disease in laboratory animals and replicate without any genetic material inside them. The achievement could lead to new tools for early detection of the faulty forms of prions that are known to cause mad cow disease in cattle and the rare, apparently spontaneous Creutzfeld-Jakob disease in humans, the researchers say. The work may also advance research into more common degenerative nervous system disorders such as Alzheimer's, Parkinson's and amyotrophic lateral sclerosis, known commonly as Lou Gehrig's disease, according to the UCSF scientists. The new research is being reported today in the journal Science by Dr. Giuseppe Legname, a neurologist in the laboratory of senior author Dr. Stanley Prusiner, who won the Nobel Prize for his discovery of prions nearly 25 years ago and has been working on their puzzles ever since. ©2004 San Francisco Chronicle

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Helen Pilcher Researchers have created a synthetic protein that makes mice display symptoms similar to those of mad cow disease. The protein, called a prion, helps to resolve a long-standing debate on the cause of certain degenerative brain conditions, such as Creutzfeldt-Jakob disease (CJD) in humans and bovine spongiform encephalopathy (BSE) in cattle. Being able to manufacture the rogue protein in the lab may also aid the development of new therapies and speedy diagnostic tests. Sporadic CJD, which accounts for 85% of prion diseases in humans, is thought to develop spontaneously. Researchers believe that healthy brain prions somehow become twisted out of shape and go on to trigger the production of more misshapen proteins. As the brain degenerates, patients lose the power of speech and movement. As there is no effective treatment, the disease is invariably fatal. But there is controversy over whether a protein alone can trigger the disease. Many researchers believe that the infectious agent must also contain genetic material, such as DNA or RNA, in order to instruct the healthy proteins to turn bad. ©2004 Nature Publishing Group

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Few ailments sound scarier than mad cow disease and its human counterparts. They incubate silently for years, slowly eating the brain away and leaving it full of holes. So it's not surprising that many people want the U.S. Department of Agriculture to test all cattle for the illness, formally called bovine spongiform encephalopathy (BSE). Certainly testing all 35 million cattle slaughtered annually would reopen trade with Japan, which has refused American beef since the discovery of a mad cow in Washington State last December. It might prevent BSE-free countries from dominating the export market. And consumers might simply feel better about their steaks, roasts and burgers. Too bad there's not much science to back up the proposal. Commercial "rapid tests" are not designed to detect the disease reliably in most slaughtered bovines. They work best on those that have lived long enough to build up in their brains a detectable amount of prions, the proteins at the root of BSE. Typically those animals are older than 30 months or have symptoms, such as an inability to stand (called downer cattle). Most U.S. bovines, however, reach slaughter weight before 24 months of age--before the tests can accurately detect incubating BSE. Most European countries recognize those limitations and target cattle 30 months and older. But using current kits on all slaughtered animals, at least 80 percent of which are younger than 30 months, may give misleading assurance about the safety of beef. © 1996-2004 Scientific American, Inc.

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| By Nicole Johnston In the relative quiet following the outbreak of bovine spongiform encephalopathy in the United Kingdom, BSE returned to the headlines recently with a sole case found in the United States and new strains of BSE prion protein identified in France, Italy, and Japan. And, in May, French researchers said they found scrapie prion in sheep muscle, showing for the first time that prions have a direct path to the grocery store.1 While these events made headlines, other discoveries in the prion world also were occurring. Researchers have started, and only started, to get to the core of some fundamental questions involving prions. One of these is whether infectivity can be established in mammals using purified prion protein; the answer appears to be no. Investigators can isolate the protein from diseased animals, but they cannot reestablish infection in an uninfected animal. Researchers aren't sure why, but theories abound: The purified prion protein may not refold correctly, or perhaps other cellular factors act as accomplices. Answering the infectivity question would help confirm the role of prions in neurodegenerative diseases associated with mammalian transmissible spongiform encephalopathies (TSEs). "With mammals, the difficulty is that nobody has been able to take normal prion protein [PrPC], convert it in a test tube, and then infect animals," says biophysicist Witold Surewicz of Case Western Reserve University, Cleveland, Ohio. And that crucial missing link is what bothers prion skeptics such as Yale neurophysiologist Laura Manuelidis. "Nobody has shown that the protein is infectious." © 2004, The Scientist LLC, All rights reserved.

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NewScientist.com news service A major advance towards producing prion-free cows that would be immune to mad cow disease has been made by researchers at companies in the US and Japan. Their principle aim is to make genetically modified cattle that produce pharmaceuticals in their milk. But the companies hope that also making the animals resistant to BSE (bovine spongiform encephalopathy) will reassure consumers. The researchers have now achieved the considerable feat of creating cell lines which have both copies of the cow's PrP gene switched off. The PrP protein can be switched to an infectious state by contact with a mutated prion. This switch causes prion diseases such as BSE in cows and variant Creutzfeldt Jakob Disease (vCJD) in humans. Making live animals from these cell lines should be relatively straightforward using cloning techniques similar to those that created Dolly the sheep. The companies say they have no intention of producing prion-free animals destined for human consumption. Instead they want to assuage public fears about pharmaceuticals derived from cow's milk, even though the process used to extract proteins from milk has already been shown to remove prion contamination. © Copyright Reed Business Information Ltd.

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Almost 4000 Britons aged between 10 and 30 may be harbouring the prion proteins that cause the human form of mad cow disease. The new estimate comes from direct analyses of human biopsies, and is much higher than epidemiological projections of the likely number of deaths from variant Creutzfeldt-Jakob Disease (vCJD). The investigators discovered three infected tonsil or appendix samples from a total of 12,674 stored between 1995 and 1999. However, because so few positive samples were found, the projected total of 3808 can only be speculative. Furthermore, harbouring the prions may not necessarily lead to vCJD. "I don't think too much should be read into our findings, but they should be investigated further," says David Hilton, of the Derriford Hospital in Plymouth, UK, who led the study. He notes that only one of the three positive samples matched the usual pattern of prion accumulation seen in confirmed vCJD cases. © Copyright Reed Business Information Ltd.

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NewScientist.com news service A massive research programme to find out whether BSE is circulating in British sheep has turned up its first suspicious result. But while scientists say the sheep did not have conventional BSE, they cannot rule out the possibility that it could have had a new form of mad cow disease that has adapted to sheep. Britain's Department for Environment, Food and Rural Affairs has announced that the Veterinary Laboratories Agency in Weybridge, England, had found "a type of scrapie not previously seen in the UK". Scrapie is a sheep disease similar to BSE which is not generally thought to harm people. DEFRA said the disease-causing prion detected in the sheep's brain "had some characteristics similar to experimental BSE in sheep", but that on other tests it resembled neither BSE nor "previously recognised types of scrapie". The UK's Food Standards Agency said in a statement: "Uncertainties still remain on this issue. However, based on the best scientific evidence to date, we are not advising against eating lamb and sheep meat." © Copyright Reed Business Information Ltd.

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By IRA DREYFUSS, Associated Press Writer WASHINGTON -- The Agriculture Department is planning a tenfold increase in the number of cattle tested for mad cow disease in response to discovery of the nation's first case of the disease last December. The department announced plans Monday to test more than 221,000 animals over a 12- to 18-month period beginning in June. Included would be 201,000 animals considered to be at high risk of bovine spongiform encephalopathy, or BSE, because they show symptoms of nervous system disorders such as twitching. Random tests also will be conducted on about 20,000 older animals sent to slaughter even though they appear healthy. Those tests are aimed at sampling cattle old enough to have eaten feed produced before 1997, when the Food and Drug Administration banned the use of cattle tissue in feed for other cattle. Copyright © 2004, The Associated Press

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IRA DREYFUSS, Associated Press Writer The Agriculture Department said Tuesday its meat recall from the nation's first case of mad cow disease was nearly four times larger than previously disclosed, but dismissed the size as irrelevant. The government said the recall grew to 38,000 pounds from the 10,400 it announced Dec. 23, when the government reported that a slaughtered Holstein cow in Washington state had tested positive for the brain-wasting disease. Officials had originally set the recall at 10,400 pounds after determining that Vern's Moses Lake Meats in Moses Lake, Wash., had mingled meat from the infected cow with meat from 19 other head of cattle on Dec. 9. ©2004 Associated Press

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Similarities Between Chronic Wasting Disease and Mad Cow Boost Funding to Discover How the Former Spreads By Marc Kaufman, Washington Post Staff Writer Following the uproar triggered by the discovery of the first known case of mad cow disease in the United States, researchers and regulators are focusing new attention on a similar disease afflicting hundreds or thousands of "mad" deer and elk that roam freely across large parts of North America. Scientists have found no instances in which the disease in these animals has jumped the species barrier to people, cattle or other animals. But they say that possibility is both real and worrisome. The condition, known as chronic wasting disease, is also thought to be caused by prions, the misfolded proteins found in mad cow disease, or bovine spongiform encephalopathy (BSE). But the deer and elk version of the disease spreads far more easily both in the wild and in captive herds. © Copyright 1996-2004 The Washington Post Company

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Scientists are trying to genetically engineer cattle that can't get mad cow disease. As this ScienCentral News video reports, a cloned cow would be a tool for further research on the disease. Federal officials announced the U.S.'s first case of mad cow disease, or bovine spongiform encephalopathy, last month. "Mad cow disease is here in the country, on this continent, in North America," says Will Eyestone, professor in the department of large animal clinical science at Virginia Tech. "It is a disease of concern. The more we know about this disease, the better chance we have of controlling it effectively." Unlike other diseases commonly caused by a virus or bacteria, scientists believe mad cow disease is caused by an infectious form of a type of protein called a prion (short for proteinaceous infectious particle). Inside the brain cells of mammals, some types of prions can alter cell structure, destroy the central nervous system, and lead to fatal illnesses such mad cow disease in animals or new variant Creutzfeldt-Jakob disease in people. © ScienCentral, 2000-2003.

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