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Shocking test results from Switzerland
Official response of the Swiss Reference Laboratory for Animal TSE
Official reply to criticism from New Scientist author
Is the USDA too "chicken" to apply Swiss test to US herds?
EU Panel: Lift British Beef Ban
'Shunned' Nobel-winner will head new [UK] research into BSE
Prusiner won't eat beef
Scientist warned of BSE crisis 10 years before export ban
Mad Cows And Milk Gate: book ordering information
Blood froma CJD donor: one family's perspective on notification

Shocking test results from Prionics: BSE's hidden horror

Wed, 13 Jun 1998 By Debora MacKenzie 10June 98 New Scientist
Hundreds of thousands of apparently healthy cattle could be infected with BSE, new Swiss data suggest. For every case of mad cow disease in Switzerland, more than 100 animals may be "silently" carrying the infection. If this pattern holds true in Britain, the number of British cattle carrying the disease last year will have exceeded 450,000.

Last year, Switzerland started slaughtering herds in which a case of BSE had been confirmed. The Swiss Federal Veterinary Office then began looking for signs of BSE in the brains of these apparently healthy cattle. These tests have just been repeated using a sensitive diagnostic test developed by Prionics, a company in Zürich. In the Prionics test, brain tissue is homogenised, then treated with an enzyme to break down proteins apart from the rogue form of PrP, the protein that becomes misshapen in BSE. The mix is then put on a gel in an electric field, which separates the remaining protein fragments. Malformed PrP is detected using an antibody that binds tightly to the protein. Previous tests of this type, called Western blots, have taken three days.

"We can have a result in 12 hours, before a carcass leaves the slaughterhouse," says Markus Moser of Prionics.

Only one or two cases of BSE typically occur in each affected herd in all countries in which the disease has shown up. "The official theory is that only the sick cows ate a lump of infectious feed," says Moser. "But other cattle may be infected, and just haven't shown symptoms."

The Prionics test has confirmed this. Of 1761 healthy cows slaughtered in the culling programme, 8 tested positive for BSE. Six of these were also picked up by the veterinary office using other tests. Eight infected cows out of 1761 gives a rate of "silent" infection of 4.5 per thousand animals--more than 100 times Switzerland's 1997 rate of clinical BSE.

The Swiss government and Prionics will start testing the brains of 3000 randomly selected cattle at more than 20 slaughterhouses later this year, to see if the same rate of infection holds for herds in which BSE has not yet been recorded. Two abattoirs say they will screen all slaughtered cattle. Epidemiological data suggest that a similar pattern may emerge.

If so, says Bruno Oesch, head of Prionics, "then 1800 subclinical cases may have ended up on the table" in Switzerland last year. No one has tested for subclinical BSE infection in Britain. But if British herds contain more than 100 infected animals for every one with obvious symptoms, the number of subclinical cases in 1997 would have been around 460 000.

The Ministry of Agriculture, Fisheries and Food (MAFF) says that only older cows are likely to pose any risk of infecting people. And since 1996, all British cattle older than 30 months have been destroyed. "This removes the possibility of any animal harbouring infectivity from entering the food chain," claims a MAFF spokesman.

But some of the government's scientific advisers remain worried about the risks posed by subclinical infection. John Collinge of Imperial College London, a member of the Spongiform Encephalopathy Advisory Committee, last week told the official BSE Inquiry of his fears that some cows may be carrying a silent infection that could be even more dangerous to people than overt BSE:

"It may be that there is rather more infectivity in muscle or other tissues in those animals and that is why they do not have a brain disease." Collinge has tried to get MAFF to look for subclinical infection using sensitive tests like the one developed by Prionics, but with no success. "I have raised that several times," he told the inquiry. MAFF is now considering plans to study subclinical BSE, but could provide no details. From

New threat as beef ban is lifted

11 Jun 98 -  By Charles Arthur and Katherine Butler in Brussels ...Independent
British beef is safe to eat, the European Commission said yesterday - just as new scientific data emerged suggesting that beef in Britain and all over Europe may still be infected with mad cow disease .

The Commission yesterday gave its support to a scheme that would allow exports of British beef from BSE-free cattle born after August 1996. But simultaneously, a study from Switzerland revealed that for every cow found to have bovine spongiform encephalopathy (BSE), 100 more may be harbouring a "silent" form of the illness .

If confirmed, the findings could deal a blow to hopes of reviving Britain's L500m beef export industry. That was choked off in March 1996, after the previous government admitted a link between BSE exposure and the fatal human illness of "new variant" Creutzfeldt-Jakob disease (v-CJD).The Swiss findings suggest that many cattle which now go into food, or are used to make animal feed, are in fact still infectious, even though they are "subclinical" - that is, showing no signs of the disease.

The meat from such animals could be infectious, some scientists believe. Professor John Collinge, a leading British expert in BSE and CJD, told the BSE inquiry last week: "It may be that there is rather more infectivity in muscle or other tissues in those [subclinical] animals, and that is why they do not have a brain disease.

"It would also mean that any country which has had cases of BSE - which in Europe only excludes Italy - could have hundreds or even thousands of cattle which carry the disease , yet may not show it during their lives.Professor Collinge said yesterday: "If there's a substantial degree of subclinical infection, it could affect other countries. But I think measures in the UK are adequate."

If implemented, the Commission's decision could lead within months to the end of the worldwide export ban. The proposal is for a scheme to allow overseas sales of beef from BSE-free cattle born after August 1996.Franz Fischler, the EU agriculture commissioner, steered the proposal through.

Yesterday he said: "We do feel British beef is safe. If we did not, we would not have made this recommendation".Jack Cunningham, the agriculture minister, welcomed the proposal - but reminded farmers "it is only a proposal". He warned of tough negotiations ahead, adding that some of the conditions attached were "unnecessary and difficult".

These conditions would allow only deboned fresh meat from animals aged between 6 and 30 months, and born after 1 August 1996 - the date when meat and bone meal was banned. Calves of BSE-affected animals would still be banned, and all animals born after August 1996 to cows with BSE would have to be slaughtered.Until the Swiss results emerged, the result had seemed a major political breakthrough for the British government.

The data, reported today in New Scientist, result from the examination of the brains of healthy cows from herds slaughtered where one or more cases of BSE were found. Using a rapid test developed by the Zurich-based company Prionics, researchers found that eight of 1,761 apparently healthy cows were actually harbouring BSE .This is more than 100 times the official rate of BSE in Switzerland. The Swiss government now aims to repeat the experiments among cattle from non-BSE herds, to see whether "silent" BSE exists generally among its national herd.

'Silent' mad cow disease poses sinister new threat 460,000 UK cattle could have it

June 11, 1998 Aberdeen Press and Journal
A SINISTER new BSE threat emerged last night - just as the Government was celebrating a breakthrough in moves to have the British beef export ban lifted. According to the findings, reported last night by New Scientist magazine, hundreds of thousands of apparently healthy cattle could be "silently" infected with mad cow disease. If the results hold true for Britain, around 460,000 cattle would have been carrying BSE last year without showing any symptoms.

...

Prof Collinge told the hearing he had tried several times to persuade the ministry to look for sub-clinical infection without success. MAFF is now said to be considering plans for a sub-clinical BSE study but could provide no details. MAFF said in a statement it had long been acknowledged there may be cattle carrying BSE which do not show clinical signs of the disease. The offal ban introduced in 1989 was intended to deal with any risk from infected cattle showing no symptoms by preventing their high -risk tissues entering the human food chain.

The statement added: "The Swiss data is based on animals culled from BSE affected herds. If there are animals incubating the disease they are most likely to be in such herds (this is the basis for the selective cull in the UK). It is not sensible to extrapolate from these herds to the population as a whole as seems to have been done in the New Scientist article. To do so would over-estimate the apparent incidence." It said the Prionics test was one of several under development. "MAFF have been considering the application of such tests for some time," said the statement. "Before they can be used these tests must be properly validated so that positive and negative results can be properly interpreted."

At its last meeting SEAC approved in principle a MAFF proposal to examine the possibility of subclinical infection in UK cattle. A detailed proposal to examine cattle over 30 months of age would be presented at the committee's next meeting. "We cannot say at this time which test will be used but Prionics' test is certainly one of the possibilities," said the statement.

Official response of the Swiss Reference Laboratory for Animal TSE

Fri, 12 Jun 1998
Prof. Marc Vandevelde
Institute for Animal Neurology, University of Bern, CH-3012 Bern and 
Dr. M. Doherr
Institute of Virology and Immunoprophylaxis (IVI), Ch-3012 Mittelhaeusern 
The Swiss reference laboratory for animal TSE (reference lab) is located at the Institute of Animal Neurology at the University of Bern. In order to determine true incidence of bovine spongiform encephalopathy (BSE) in Switzerland, the reference laboratory has been contracted by the Swiss government to monitor TSE's and to conduct studies on the presence of preclinical BSE in the Swiss cattle population. These studies included the development and validation of BSE tests, development of transgenic mice, sampling and examining CNS material from Swiss cattle and epidemiological investigations. The reference lab is not part of the Swiss Federal Veterinary Office as indicated in the article by Deborah MacKenzie of the New Scientist of Today.

We are dismayed by the serious inaccuracies in the article about the "shocking" BSE test results in Switzerland. The interpretation of the results in respect to the validation of the diagnostic tests and true incidence of BSE in the cattle population in our country is unscientific and potentially misleading. We hereby present a brief account of the presented errors and the scientific data and conclusions derived from our studies to date.

Critical statements in New Scientist article to be addressed

1. "Hundreds of thousands of apparently healthy cattle could be infected with BSE, new Swiss data suggest. For every case of mad cow disease in Switzerland, more than 100 animals may be "silenty" carrying the infection"

2. ""The official theory is that only sick cows ate a lump of infectious feedÄ.but other cattle may be infected, and just havent shown symptoms". The Prionics test has confirmed this. Of 1761 healthy cows slaughtered in the culling programme, eight tested positive for BSE. Six of these were also picked up by the veterinary office using other tests."

3. "Eight infected cows out of 1761 gives a rate of "silent" infection of 4.5 per thousand animals, more than 100 times Switzerlands 1997 rate of clinical BSE."

4. "Epidemiological data suggest that a similar pattern may emerge."

Scientific background and response

In 1997, all herd mates of Swiss BSE cases born before December 1990 (the date of the Swiss ruminant feed ban) and all herd mates of Swiss BAB cases (regardless of age) were culled. These animals were examined in the reference laboratory by histology and immunocytochemistry (IHC) to demonstrate the accumulation of the protease resistant (infectious) prion protein. Immunocytochemistry has been used to detect a variety of antigens, including prion protein, in tissue sections since many years. The latter technique involves antibodies specifically directed against the bovine prion protein which we had raised in rabbits. It is known from experimental pathogenesis studies in BSE in cattle that accumulation of the infectious prion protein becomes detectable by immunocytochemical methods before spongiform change and clinical signs occur. Preliminary data suggest that this may be up to 6 months prior to the occurrence of clinical signs (Wells et al., 1998). Of the animals tested, 6 were found to have accumulation of the infectious prion protein in the brainstem. Three of those in addition had mild spongiform changes.

All samples were made available to the company Prionics (B. Oesch, M. Moser) during a validation phase of a BSE test developed by Prionics at the University of Zuerich. The Prionics test is also based on the detection of infectious prion protein with western blot (WB) techniques using antibodies following electrophoresis of brain tissue extracts. The WB technique exists since many years and is widely used in the biomedical sciences. The use of the WB for the detection of prion protein in BSE was first published in 1992 in Great Britain but remained essentially a research tool. Prionics has modified this technique in such a way that large numbers of samples can be examined in a short period of time, thus allowing its use as a routine diagnostic test. Prionics has also developed excellent monoclonal antibodies against the infectious prion protein.

The WB validation also included confirmed cases of BSE as well as confirmed negatives. The results were evaluated by Prionics together with the reference laboratory and a final report written and signed by the two laboratories in spring of 1998 was submitted to the Swiss FVO. The Prionics test detected 6 positive cases among the 1761 animals culled in the slaughter programme. Four of these cases were identical to the ones found by the reference laboratory. The 2 remaining cases detected by Prionics had been negative in the IHC. In contrast, the 2 additional cases that were detected with standard methods were negative in the Prionics assay. Thus a total of 8 positive reactors were found, 4 of which overlapped.

Both Prionics and the reference laboratory agreed in the final report to declare the 4 overlapping reactors definite positive cases. The remaining 4 animals were considered questionable, requiring further investigation. Meanwhile, all 8 reactors have been examined, again in a blinded fashion, in the laboratory of Prof. Kretschmar, University of Güttingen, Germany using a new very sensitive assay in tissue sections. The new assay confirmed the diagnosis in one of the two questionable cases diagnosed by the reference laboratory. The two questionable cases diagnosed by Prionics were not confirmed. In total, 5 out of 1761 herdmates of confirmed BSE cases were confirmed PrP positive and considered preclinically infected.

It is of no surprise to scientists that for any disease with a long incubation period (time between infection and outbreak of clinical signs), one has to expect a larger proportion of the infected population to be in the incubation period (preclinically infected) than showing clinical signs. This is especially true in the case of BSE where the exposure to contaminated meat and bone meal (MBM) occurred over a period of several years and where the incubation period can vary considerably between individual animals: Swiss BSE field cases were between 31 months and 11 years old with an average of 5-6 years.

Until recently, no studies have been reported on the prevalence of preclinical BSE in the slaughter animal population. The limiting factor for these studies remains the fact that the tests currently available only detect animal in the late incubation period (within 6 months of the outbreak of clinical disease). Estimates of preclinically infected animals that were slaughtered on a routine basis and that entered the food chain undetected are based on modelling approaches. A mathematical model developed in 1996 in Great Britain on the basis of the MAFF BSE statistic estimated that a large number of preclinically infected cattle had already entered the human food chain in the UK (Anderson et al., 1996).

A backward calculation model on the expected number of animals that had to be infected during their first year of life to produce the number of observed cases from each birth cohort since 1984 (the birth year of the first BSE case observed in Switzerland) was performed for the Swiss BSE epidemic. We estimated that the maximum number of preclinically infected animals in Switzerland was reached in 1990 (with potentially 1200 affected animals among the 900000 heifers and cows in the population that year). After 1990, most likely as a result of the feedban, the model shows a pronounced downward trend in the expected number of preclinical cases in the general cattle population with less than 100 preclinical cases still present in the 1997 population. Each year, approx. 70000 heifers and 200000 cows are slaughtered in Switzerland.

The results of these studies should be interpreted as follows:

- The sensitivity of the Prionics WB is similar to the one of the IHC and certainly not higher as suggested by the media. With the sensitivity of the techniques available to date, animals in incubation (preclinical cases) will be detected by demonstration of the accumulation of the protease resistant protein in the final 6 months of the incubation period only;

- Demonstration of accumulation or infectious prion protein, even in the absence of clinical signs and spongiform changes, is a strong indication for BSE; however, as with every test system, false positive results are possible;

- In contrast to the statement made by D. MacKenzie, researchers have always suspected a large number of preclinically infected animals in the population. For that reason, measures have been taken (destruction of slaughter animals over the age of 30 months in the UK, limitation on the use of high risk organs like brain and spinal cord) to prevent the spread of infection from products of slaughtered preclinically infected animals to humans;

- Of the 1761 herd mates of BSE cases destroyed in the culling programme, 5 positive in IHC and the new assay, i.e. in the late stage of incubation, not 8 as stated in the article. It is incorrect that these preclinical cases of BSE were detected (the first time) by the new "sensitive" assay of Prionics; the cases had been identified before in the frame of a study conducted by the reference lab and, together with other samples, were used for the validation of the Prionics western blot.

- We consider the culled population of BSE herdmates a high risk group with proven exposure. The prevalence of preclinical disease observed within this cohort should therefore be considerably higher than the true prevalence of preclinical BSE cases in the general cattle population. Any direct extrapolation showing huge numbers of preclinically infected animals for 1997, as done by D. MacKenzie, is not appropriate;

- As demonstrated before in the Swiss simulation, we expect (with advancing time) a further decreasing proportion of preclinically infected animals in the Swiss cattle population. This is due to elimination of exposure (feed ban and similar measures) and the decrease in animals from exposed birth cohorts that are still present in the population (aging of the cohorts);

- We currently have no epidemiological data to support that "a similar pattern" (high prevalence of preclinical infection) may emerge in the planned prevalence study at slaughter, as incorrectly stated by D. MacKenzie.

Supporting our line of reasoning is a statement published by the moderator of ProMED as a response to D. MacKenzies article:

"One should remember that these 1761 healthy cows were taken from herds in which one or more clinical BSE cases had been previously identified and slaughtered. And 6/8 Prionic +ve animals showed positive on other veterinary tests suggesting that if they had not been slaughtered some if not all six would have eventually demonstrated BSE. It has been held in the UK for some time now that preclinically affected animals would have been slaughtered and butchered as a matter of course. What risk such animals pose is argumentative with the current restrictions. - Mod.MHJ"

References

- Anderson R.M. et al. (1996). Transmission dynamics and epidemiology of BSE in british cattle. Nature 382(N6594): 779-88.

- Wells G.A. et al. (1998). Preliminary observations on the pathogenesis of experimental bovine spongiform encephalopathy (BSE): an update. Veterinary Record 142(5): 103-106.

Reply to criticism of New Scientist article on Swiss BSE results

Debora MacKenzie New Scientist 16 June 1998
Reply To Prof. Vandevelde And Dr. Doherr:

I must respond to some statements in this reply to my article in New Scientist of 12 June, "BSE's hidden horror".

1. I did not, as the authors state, indicate that the Swiss TSE reference laboratory was part of the Swiss Federal Veterinary Office. Drs. Vandevelde and Doherr state that the research I reported was contracted by the Swiss government and submitted to the Federal Veterinary Office. Sadly, it is not possible in a short news article to mention the names of everyone concerned in a research project. It is customary to mention only the agency in charge, in this case the Vet Office.

2. It is true that one error of fact entered the article, concerning which researchers identified which infected animal. As Drs. Vandevelde and Doherr point out, I said six of the eight positives were identified by their immunohistochemistry, and eight by the Western blot technique of Prionics. In fact Prionics identified only six of the eight positives; four animals tested positive with both techniques. This imprecision was not the fault of any scientists I spoke to.

I regret this error, of course. But I must emphasise that it in no way alters the article's conclusions. Each test analyses a different tissue sample, and as altered prion protein is not uniformly distributed in the brain, it is to be expected that two different tests of one cow may give different results. As was painstakingly explained to me by the scientists I spoke to in preparing this article, the bottom line is that eight animals tested positive. All the conclusions in the article stem from this result.

Drs. Vandevelde and Doherr emphasise the possibility of false positives. But as has been pointed out by others, a false negative is at least as likely as a false positive, and eight positives are at least as likely to provide an underestimate as an overestimate of the true incidence of subclinical infection in this sample.

Even if, as they suggest, I accept only five positive results as opposed to eight, then 5/1761 gives a rate of "silent" BSE infection 67 times the clinical incidence, as opposed to 107. The implications for public health are little different. The main one, of course, is the need for more tests.

3. Drs. Vandevelde and Doherr discuss models of the predicted incidence of preclinical BSE at length. I do not understand their criticism of my article in this regard. Surely real results are always preferable to models.

Such measurement is especially important given the assumptions on which the models are based. These start with the observed clinical incidence of BSE, and add an estimate of the incubation time, to arrive at the number of animals which have not yet shown symptoms but are infected, and thus the total number of infected animals at any time. As I understand it, two things will cause this number to be too low: an underestimate of the incubation time; and a substantial number of infected animals which do not ever express BSE in the lifespans available to them, and hence the existence of a large amount of infection not reflected in the clinical incidence.

Incubation times may well be underestimates if they are based on the earliest time before the onset of symptoms at which tests are sensitive enough to detect infection, which could be well after the time of infection. But it is the assumption, as Martin Hugh-Jones pointed out on ProMed, that "if they had not been slaughtered, some if not all would have eventually demonstrated BSE" that is most crucial, as if they did not, this would imply that there is some burden of infection not reflected by clinical incidence.

There is reason to suspect that the animals which tested positive in this survey would not have gone on to display symptoms in the time they would have lived if there were no herd slaughter policy. As the Swiss Vet Office reports, 97% of the 272 BSE cases in Switzerland were the only animals in their herds to develop symptoms. Most occurred at a time when subsequent incidence in their herds could have been observed, between the first Swiss case in 1990, and the start of herd slaughtering in January 1997. The animals surveyed in this study were all from herds in which one case had appeared. The great rarity of second cases in affected herds would suggests that at least some of these animals would not have gone on to display clinical symptoms before they were slaughtered for the normal reasons.

Drs. Vandevelde and Doherr state that because researchers "have always suspected a large number of preclinically infected animals" because of modelling, they have instituted such safeguards as the slaughter of animals older than 30 months. The British 30-month rule has never been empirically tested by looking for infection before that age in apparently healthy herds in Britain.

Obviously, it is of greatest priority to do such tests. This is why I examined the implications IF this incidence IS confirmed more widely. It was also important to make these results more widely available to the scientific community than they were by the Swiss Veterinary Office. The complete text of that report, contained almost at the end of "Fact Sheet: BSE" on the Vet Office Web site, is:

"Altogether, 2800 animals on BSE farms have been killed, including 180 offspring... The offspring and other animals killed are being examined and investigated in an attempt to give indications as to the origin of BSE and the route of infection. The examination of the offspring showed no indications of BSE. 6 of 1719 had changes showing that the animals were affected with BSE. This result does not surprise as the animals belonged to a high-risk population."

The 6 are presumably those detected by Drs. Vandevelde and Doherr. But 2800 minus 180 does not equal 1719, or even 1761. Are more results forthcoming?

4. The statement above that BSE herds are an unusually high-risk population can be questioned. Drs. Vandevelde and Doherr say there is no epidemiological evidence to suggest that the incidence of subclinical infection may be similar in herds which have not had animals with clinical symptoms. The scientists to whom I spoke in preparing this article explained to me in great detail why they think there is. As noted, the vast majority of BSE cases are the only ones in their herds. This means that the next case of BSE is more likely to arise in an apparently unaffected herd as in an affected one. Scientists to whom I spoke in preparing this article therefore suspect that the incidence of subclinical infection in apparently unaffected herds may be not much smaller than the incidence in affected herds. But of course, it is necessary to do the work.

5. Drs. Vendevelde and Doherr accuse me of stating that the Prionics western blot is more sensitive than their technique, and that the cases were detected for the first time by Prionics. The article does not make these statements.

6. The "extrapolation showing huge numbers of preclinically infected animals for 1997 as done by D. MacKenzie" was not done by me. It was done, as cited, by one of the scientists to whom I spoke, and subject to the clear caveat that IF the incidence revealed by this study was paralleled in the general population, THEN that would be that number of cases.

Apart from the imprecision concerning whose test got which result -- which I of course regret -- my article reports the results and implications of an important piece of science, for which the Swiss are to be congratulated. It is to be hoped that other countries will soon do similar tests.

Testing for BSE: New Scientist follow-up

July 4/98 New Scientist
The article on BSE in Switzerland quoted one of us as saying that "1800 subclinical cases may have ended up on the table" last year (This Week, 13 June, p 4). The full quote was: "If you assume the same incidence in the general population, 1800 subclinical cases may have ended up on the table. But the actual number of subclinical BSE cases present in the current population really has to be determined." The general incidence of subclinical BSE in Switzerland may be less than in the culled herds tested so far.

The results presented in the article were also not represented entirely correctly. Out of 1761 animals examined, four animals tested positive by both immunohistochemistry and the Prionics immunoblotting test. Three of these animals tested positive for spongiform change. In addition, two further animals tested positive by immunohistochemistry alone and another two by the Prionics test alone. The differences between the test results may lie in the techniques used or may simply represent the fact that the two methods cannot be performed on the same tissue sample.

In conclusion, three animals each tested positive by three different methods and one by two methods, while four animals were positive by only one method.

Markus Moser
Bruno Oesch
Prionics, Zurich

The Swiss reference laboratory for animal transmissible spongiform encephalopathy at the Institute of Animal Neurology, University of Bern, has been contracted by the Swiss government to conduct studies on the presence of preclinical BSE in the Swiss cattle population. The Prionics test detected six positive cases among the 1761 animals culled in the slaughter programme. Four of these cases were identical to the ones found by the reference laboratory. Two cases that were detected by the reference lab were negative in the Prionics assay. Thus a total of eight positive reactors were found, four of which overlapped.

All eight have been examined by Hans Kretschmar of the University of Gottingen in Germany using a new assay which confirmed the diagnosis of one of the two questionable cases identified by the reference laboratory. In total, we now consider five cows to be preclinically infected.

For any disease with a long incubation period, one has to expect a larger proportion of the infected population to be in the incubation period than showing clinical signs. Until recently, no studies have reported the prevalence of preclinical BSE. Estimates of preclinically infected animals that entered the food chain undetected are based on modelling approaches. We estimate that the maximum number of preclinically infected animals in Switzerland was reached in 1990, with potentially 1200 affected animals. Our estimate is that fewer than 100 were still present in 1997.

We consider the culled population of BSE herdmates to be a high-risk group. The prevalence of preclinical disease observed within the cohort of culled animals should therefore be considerably higher than the prevalence in the general cattle population.

Marc Vandevelde
Institute for Animal Neurology
University of Bern, Switzerland

Marcus Doherr
Institute of Virology and Immunoprophylaxis
Mittelhaeusern, Switzerland

Why not use Prionics test in the US?

16 June 98 listserve
It sounds like it would be a very good idea to start using the Prionics test in the US as soon as possible to assure meat safety. The best thing to do would be buy up a thousand of the oldest dairy cattle that can be found in Wisconsin. My guess is that the USDA is too "chicken" to run serious tests for subclinical BSE in the US, so perhaps it would be better if the tests were run by a third party such as National Academy of Science in conjunction with consumer group and industry scientific observers.

EU Panel: Lift British Beef Ban

Wed, 10 Jun 1998 AP Online  By PAUL AMES
BRUSSELS, Belgium -- The European Commission today recommended the lifting of the ban on British beef exports imposed more than two years ago at the height of Europe's "mad cow" scare. The 20-member European Union executive body ruled British beef and most beef products from cattle older than six months and younger than 30 months should be cleared for export. That would cover most potential beef exports.

British Agriculture Minister Jack Cunningham told the BBC the decision would be "a very, very important step." However, despite the Commission's approval, the EU's complex decision-making process means it could still take months before British beef is back on foreign markets.

The decision needs approval by a panel of veterinary experts from the 15 EU nations that is scheduled to meet Friday, but the specialists are divided and if they fail to agree, the issue will be put to a vote at a meeting of EU agriculture ministers, probably in July. Germany in particular is wary about letting British beef back onto its markets, fearing that lingering mad cow fears among consumers could again drive down the price of all beef.

The EU slapped a global ban on British beef exports on March 27, 1996, after the British government acknowledged a possible link between a brain-wasting cattle ailment officially known as bovine spongiform encephalopathy and an equally fatal human condition, Creutzfeldt-Jakob disease. Fears that eating mad-cow tainted beef could cause humans to contract CJD provoked a crisis in the beef industry across Europe and cattle prices plummeted.

Although some animals have come down with BSE in other European nations, the overwhelming majority of mad cow cases have been in Britain. The outbreak was blamed on the practice of feeding cattle the ground remains of sheep and other animals. Britain banned such feed on Aug. 1, 1996, and now claims all cattle born after that ban are free from the disease. Among other measures taken to wipe out the disease, Britain slaughtered 3 million cattle judged at risk and forbade the sale of cattle-parts thought most likely to harbor the disease, such as brains and spinal cords.

The first relaxation of the ban came two weeks ago when the EU allowed exports of beef from Northern Ireland, where a special computer tracking system allowed herds to be certified mad-cow free. Before the ban, Britain's beef exports were worth $8.1 billion a year.

EU Commission to propose lifting British beef ban

Reuters World ReportTue, Jun 9, 1998 By David Evans
BRUSSELS, June 9 - The European Commission is on Wednesday expected to propose lifting a ban on mainland British beef exports more than two years after it was imposed, although any concrete decision could be months away, Commission officials said.

"The proposal is on the Commission's agenda tomorrow, and then it becomes a matter for the scientists and member states," one senior Commission official said on Tuesday. An official Commission proposal heralds the start of the European Union's long-winded decision-making process. Member state veterinary exports will have to examine it, and given its political sensitivity, they will probably pass on any final decision to EU farm ministers.

Britain's plan to resume exporting beef from animals born after August 1996 -- the date when a ban on feeding meat and bone meal to animals was fully effective -- has been with the Commission for the last nine months. The Commission's endorsement of it will be a major relief to British cattle farmers, who say the worldwide export embargo has devastated their industry and livelihoods, wiping out valuable markets worth millions of pounds a year at a stroke.

Farmers in Northern Ireland already have a green light to restart exporting beef under a different scheme. A computer system in the province, originally designed to track the spread of scrapie, meant EU farm ministers were satisfied meat could be guaranteed free of BSE (bovine spongiform encephalopathy). Northern Ireland has also had a much lower incidence of BSE, also known as mad cow disease. It remains to be seen whether sceptical member states such as Germany, mindful of powerful consumer lobbies at home, will have the same faith in Britain's scheme for the mainland.

The British government, which holds the EU presidency, has been pushing the Commission into making its proposal as early as possible, and wants to be able to go into the summit of EU leaders in Cardiff on June 15-16 demonstrating real progress on an issue which dogged the previous Conservative administration. Labour Prime Minister Tony Blair, currently on a tour of EU capitals, should at least be able to claim a proposal has been made, but probably not much more.

EU officials said EU veterinary experts may meet as early as this Friday for an exploratory meeting, although no firm decision is expected. EU officials say this is more likely to be a presentation of the scheme, and a second committee meeting, planned for June 16, could pass the final decision to farm ministers at their session set to start on June 22 in Luxembourg.

But it could be longer. If the process involving the Northern Ireland scheme is anything to go by, veterinary officials could hold the process up for months, while they conduct inspections and debate the issue in working groups. Britain will be stressing that the "born after August 1996" element of its plan eliminates any danger of infected meat entering the food chain. No animals born after that date would have been fed meat and bone meal blamed for transmitting mad cow disease.

Opponents of the scheme will be looking for cast-iron safeguards that only meat from eligible animals is exported. The EU imposed the ban on British beef exports in March 1996 after the government admitted a possible link between mad cow disease and a new variant of the human brain-wasting disorder Creutzfeldt-Jakob Disease.

Scientist warned of BSE crisis 10 years before export ban

Thu, 11 Jun 1998  By Paul Peachey, PA News 
A pioneering scientist warned that the BSE outbreak could destroy the British meat industry nearly 10 years before Europe imposed a world-wide beef export ban, an official inquiry heard today. Dr Alan Dickinson said the spread of the epidemic could have been checked if Ministry of Agriculture officials had consulted the right people.

Dr Dickinson said millions of pounds had been wasted during the BSE crisis because money was given to scientists without proper experience. "If it was not under the control of the most experienced people in the world on this subject, it would quickly spin out of control," he told the inquiry in south London.

Dr Dickinson resigned in 1987 as the head of a key research body because of the "shambles" that had blighted investigation into diseases like BSE in the 1980s. In swinging criticisms of the culture of scientific research in Britain the 1970s and 80s, Dr Dickinson said: "The problem stemmed from aspects of the administrative culture dominating veterinary issues and from the progressive weakening of the autonomy of UK science." During the height of the crisis, Dr Dickinson said, decisions should have been taken quickly by qualified scientists. But agricultural officials preferred to wait for specific evidence of BSE in cattle.

He spoke of a battle between research councils and government ministries over the reorganisation of scientific research in the 1980s under a backdrop of underfunding for his organisation. In a statement to the inquiry he said: "At this time the feeling was widespread that the slow politicisation of research councils was leaving a smaller pot of research funds from which MAFF had first call."

Dr Dickinson said he told a colleague in August 1987: "If this BSE issue is not handled properly it will destroy the meat industry." Dr Dickinson said it was obvious that the BSE outbreak by mid-1987 was getting out of control as he had heard of nearly 100 cases. But a world-wide ban was not imposed by the European Commission until March 1996.

The cost to taxpayers of the crisis has been estimated at nearly 4 billion and the Commission only this week recommended an end to the trade blockade. Twenty-five people have died from new variant CJD which has been linked to eating BSE-infected meat. Another person has the disease but is still alive, according to Government figures.

Dr Dickinson, director of the Neuropathogenesis Unit in Edinburgh until 1987, a research unit looking at BSE-type diseases, said too little government money had been channelled to them.

"There is wide agreement that very little of value has emerged from inexperienced labs given BSE funding," he said. Changes in the management of research meant short-term funding was given to projects that would take much longer to complete their results, he told the inquiry. The inquiry was adjourned until tomorrow.

Mad Cows And Milk Gate

9 Jun 1998 
MAD COWS AND MILK GATE by Virgil M. Hulse MD MPH FACPM. Former milk and dairy inspector for 13 years, paid as an expert medical consultant on the beef trial by Howand Lyman and Oprah Winfrey attorneys; a chapter on the Beef suit and trial.

Publisher Marble Mountain Publishing revised second printing, revised May 1998, 340 pages; ISBN 0-9654377-0-1 Price $20.00 plus $2.00 shipping call 1-877 MAD COWS or 1-877 623 2697 for credit card orders or call 1 541 482 2048 also available online through amazon.com

'Shunned' Nobel-winner will head new [UK] research into BSE

Mon, 8 Jun 1998  By David Brown, Agriculture Editor, Telegraph 
Apparently Professor Stanley Prusiner has been called in by the UK Government to plan new research into mad cow disease after years of rejecting his offers to help. "They approached me a month ago," Professor Prusiner said before leaving London yesterday after giving evidence at a weekend session of the BSE inquiry.

He set up a special laboratory in California in 1974 to study scrapie - the fatal sheep brain disease which is thought to have been the precursor of BSE. But he told of difficulties that the agriculture ministry in London put in his way when he tried to extend his work to cover BSE after the disease was made public in 1987.

The following May, he requested cow brain samples from the ministry. He received a holding letter in September but it was not until 1989 that he was sent the samples he needed. He could not understand the delay since "they had plenty of material to offer".

Then on June 5, 1991, he submitted a funding request to the ministry and the Agricultural and Food Research Council to develop a way of screening animals and people for the fatal brain diseases. Even now, he said, scientists knew very little about them. They did not know how many cattle were affected sub-clinically with the disease. They only knew those that had succumbed to BSE.

His request was rejected. Then in September 1996, five months after the beef crisis broke, when British scientists announced a probable link between BSE and a new variant of CJD in people, he submitted another request on the advice of John Wilesmith, the Government's senior animal epidemiologist. This was also rejected. He estimated the project cost at L5 million.

Professor Prusiner "could not understand" pre-research findings used by Professor Sir John Pattison, chairman of the Government's spongiform encephalopathies advisory committee, and others to conclude that the new variant CJD was linked to BSE. He said: "I am not convinced as a scientist that the new variant CJD is caused by BSE in cattle." But while there was "no conclusive proof", he conceded that this "seemed likely" on the basis of available evidence.

It was true that the new variant CJD had been found - apart from one case in France - in Britain, the country with the highest incidence of BSE. But he questioned why there had only been 25 cases of the new variant CJD when there had been so many cases in cattle. Professor Prusiner said: "We have no clear reason why these people have developed this disease when 10 million other people with the same environmental history did not. There is no unique behaviour trait. They didn't go out and eat cattle brains."

UK refused requests to fund BSE research-expert

Reuters North America Sun, Jun 7, 1998 By Patricia Reaney
LONDON, June 7 - Britain's former Conservative government turned down requests from one of the world's leading BSE experts to fund research that could have provided vital information about mad cow disease and its human equivalent. Professor Stanley Prusiner, the 1997 Nobel Laureate in Medicine, told a weekend hearing of an official inquiry into BSE that the government had
refused "multiple" requests
he made in 1991 and 1995.

The research "could prove to have been very important. I just don't know," he told the panel investigating the handling of the crisis. "If we had had this money we would have broadened our research programme."

Prusiner won the Nobel Prize for his discovery of the prion, a tiny brain protein whose mutation is thought to be the cause of bovine spongiform encephalopathy (BSE) and the human brain-wasting illness Creutzfeldt-Jakob disease (CJD).

The American professor of neurology and biochemistry has been working on BSE for 25 years. The outbreak of an epidemic that decimated British herds in the 1980s, and Britain's warning in 1996 that BSE could be linked to a new variant of CJD, highlighted the importance of his research. Ironically, the proposed project that Britain's Ministry of Agriculture, Fisheries and Food refused to fund in 1991 was titled, "Assessing the risk of BSE to humans."

Britain's new Labour government set up the independent inquiry in December 1997 to review the history of the emergence of BSE and CJD and the action taken in response to it. Hearings started in March. Scientists, pathologists, veterinarians, nutritionists and government officials will testify before the inquiry's three-member committee, headed by Appeal Court Judge Sir Nicholas Phillips, reports its finding to the government in June 1999. During his testimony, Prusiner praised scientific research papers investigating the link between BSE and the new strain of CJD but he said none, in his opinion, offered conclusive scientific proof.

So far 25 people in Britain have died and another is still suffering >from the new strain of CJD, which, unlike CJD, affects mainly young people and is believed to be caused by eating contaminated beef. Prusiner said if BSE is the cause many more people should have been affected. There is no clear reason why they got the disease and millions of others did not. "There is no single dietary habit common to all of them and different to everyone else on this island," he said.

He refused to speculate on whether the government had been right to issue its 1996 warning of a possible link between BSE and the new strain of CJD. "We don't know if the food supply is contaminated," he said. "The government has a responsibility to the people to make sure things are safe."

The warning led to a European Union ban on the export of British beef that was ruinous for the meat industry. It also resulted in the slaughter of millions of cattle to eliminate the epidemic and reduce the risk of any possible contamination to humans. Prusiner told the committee that he did not think CJD was an auto-immune or infectious disease. He also said his team and other researchers were already trying to identify drug therapies that will block the binding of the mutated prion to an essential protein.

When asked by the committee if he had continued to eat meat, Prusiner answered "No." But he emphasised that his decision was an emotional, not a scientific response. "It wasn't an appetising thought," he said.

Blood from CJD donor: one family's perspective on notification

9 June 98 correspondence [Source deleted to protect privacy]
"Good Afternoon Ladies & Gentlemen. First of all I am honoured at being invited to attend and speak at this conference. I will tell you about my sons situation and then about how I came to the decision of not Notifying people who have received tainted blood.

My son received Albumin. in 1990. I was notified of the recall in 1996, It went as follows: to date there has been virtually no evidence that your child will develop CJD. Therefore, there is little reason for concern. But we also know that the more informed you are about this situation, the more assured you will feel. How can anyone get any reassurance from that letter...it didn't even state it was a theoretical problem and with stating that there is virtually no evidence does not state that there are no confirmed cases.

I attended their conference they held in May 1996. I left that conference in dismay, overwhelmed by the information and gravely worried about my son.

I was left on my own to deal with this anxiety, with no other support given, it was horrendous. It was a time of such limited information and CJD being the disease of many unknowns.

In the two years that followed I did research at whatever means were available, the library, I wrote Health Canada and the Canadian Red Cross. Until I went on the Internet I found information to be limited. Any mailings were just of statistical information, and some even said to discuss with your family doctor....many of them don't even know anything about it and you have to educate them.

My initial reaction was that I was glad I was told, I felt it was my right to now......now I don't think I should of been told. It causes me much pain and worry. Especially the unknowns of the disease. Upon asking questions as to whether my son would be allowed to donate blood the response was one I had not expected it was then that I changed my opinion and thought.

Why bother informing us at all then? To cause myself as a mother much pain and worry for 2 years it will be something I will carry with me to my grave. You can't even imagine what I and others have lived thru, we are told of this horrific disease and our relation to it, and of the recall which seems important enough. But in the same breath I am told it is no big deal, why are you so worried and I am treated as such. It is my son we are talking about here.

I was and am very frustrated with all of this. I assumed the main reason I was told was so that my son wouldn't be able to give donations of any sort blood or organs until we get answers, until I was told it was a step no-one was prepared to make. So if years down the road when we get some answers other people do not have to go thru the pain I have endured. With United States recently suggesting to use recalled Albumin in emergency situations when it is considered to be so risky it makes you wonder if the crisis is not so great that I had to of been told and others alike. Unless you research this on the Web and know who to ask you are left with only assumptions.

When speaking with a representative from RED CROSS she said not to worry because by the time your son has become of age to donate blood we will have some answers. My response to her was what about the teenagers that got these letters and would be eligible to donate this year. are we reinfecting with infectious blood by doing nothing preventative with recipients of tainted blood. I was really emotional with her I really think she thought I was over-reacting to it all, and maybe I was but it was important enough to tell me so why shouldn't I react this way.

With the decision to inform being based on ethical requirements of what to do and not whether the risk is real seems ironical that we are told of this one and not of other possibilities. It seems it is alright with some hospitals not to notify and with others to notify, those notified I feel have been given an injustice, you took away my piece of mind and sometimes I think my sanity. With researchers suggesting that if the incubation period for CJD is 30 years and over 1/2 of all donor pools would be contaminated would that now mean that in time at least 1/2 the population would need notification letters eventually and with all the products that contain blood and blood products would it now make it impossible to trace all the uses of such products, for example shots which contain Albumin. I do not rationalize now why we are told. I feel it would be more beneficial to keep a registry of the donor recipients to be used when the time of proof and answers are available.

If the risk from acquiring CJD from blood is theoretical, not small or really small but theoretical why are we the only ones being informed of such a possibility. There are many other situations which are theoretical, such as the risk that cancer could be transmitted by blood transfusion or that allergies could be transmitted. Since the risk is only hypothesized and not demonstrated in these cases as well why are they not notified if you set a precedent with one then you must follow thru in all areas. Not just pick one.

We do know that this disease has been around ever since transfusions were begun I believe in the past a connection would of already been made if it was possible for CJD to be transmitted this way when I think of the constant transfusions some people need to be able to live. I have spoken to a woman who has received some 30 recalls there are many of these people and they would of succumbed to CJD if it was possible. I do believe that recalls of tainted blood should continue but as we know the blood could of already been used these Recipients of this blood should be kept in a registry . I can not believe that anyone can be held liable for doing such a practice the unknowns of so much with any disease is cause for research to get the answers we all need, not dropping it in the laps of recipients and expecting us to continue on as normal I wonder how you expected us to react to such information. I am fortified in knowing that Health Canada and the CDC are presently doing studies on risk factors of blood. It is unfortunate that these studies were not completed before sending out notification letters.

I have since spoken to other parents thru CJD VOICE, which is a support network for the people involved with CJD either thru losing someone to this horrendous disease or receiving notification, it also tries to raise awareness among the general public and increase funding. These parents who have been notified are terrified and frightened and want to know what their chances are of their child getting CJD really are and like one father asked how long do they have to live. They feel like they have no where to turn for answers, it is all right to logically expect us to understand that the risk is minimal if at all. But emotions usually rule out logic. I am fortunate on one aspect because my child is not inflicted with any other medical problems I can only imagine what they are going thru.

In other countries they are not telling the recipients....such as in the Netherlands they did not want to alarm the recipients which I feel is a good thing as once you are told it is hard to listen to the logic without concrete proof. This is our loved ones, our children, someone we are supposed to protect, but in life as we know it we cannot protect them from everything.

Other thoughts I have gone thru are how do I tell my son about this, if something was to happen to me, would he really need to know just because someone felt we needed to know. I have also felt do I need to stop him from donating blood or organs until research proves to me that it is alright for him to do so. It was important enough for me to be notified but not enough for him to be considered a risk factor. As long as I am alive he will NOT be told it would be too much for him as I am sure it is too much for alot of people.

At some point I have also believed the only reason we were told was because of the legal aspect when I rationalize the history it is the only reason I can come up with. Noone can be held responsible for the unknowns of any disease, it would be a greater benefit to have more knowledge, not have hundreds of people feel like they are lepars in society. I am also worried that if others do find out about my son's situation in our community he would become an outcast. We have seen that in the past with other diseases.

There is much confusion when you receive this letter of notification and when you are done researching all that is available you become frustrated, angry and many tears are shed. I believe some of the examples I have stated illustrate the reasons for such emotions I have personally thought of it as a pendulum swinging and each side has it's own emotions, and each side its own rights and wrongs.

Never-the less I am still left with my sons notification letter nothing will change what has already been carried out but what I am doing is hoping for a turnaround in not telling more people and having them deal with such an unjust and inhumane thing such as notifications for theoretical risk. I would also add where would some of us be without these products today. Thank-you"

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