Solid evidence for blood infectivity
Distribution of prions in normal adult blood
FDA concerns with TSE agents and safety of biologics.
Prions found on udders, skin
Gambetti won't eat CWD venison, Schonberger would
False alarm on Cordelia Gummer
France and EC face legal battle over beef
Top BSE official forced to step down
Transfusion, Vol. 39, No. 11, 1169-1178, November 1999 P. Brown, L. Cervenkova, L.M. McShane, P. Barber, R. Rubenstein and W.N. DrohanSolid evidence from experimentally infected animals and fragmentary evidence from naturally infected humans indicate that blood may contain low levels of the infectious agent of Creutzfeldt-Jakob disease (CJD), yet blood components have never been identified as a cause of CJD in humans. [Absence of evidence is not evidence of absence. -- webmaster]
Blood components and plasma fractions were prepared from the pooled blood of mice that had earlier been infected with a mouse-adapted strain of human transmissible spongiform encephalopathy (TSE). Infectivity bioassays were conducted in healthy mice, and the brains of all assay animals dying during the course of the experiments were examined for the presence of proteinase-resistant protein.
Infectivity in the blood during the preclinical phase of disease occurred in the buffy coat at infectious unit (IU) levels between 6 and 12 per mL and was either absent or present in only trace amounts in plasma and plasma fractions. Infectivity rose sharply at the onset of clinical signs to levels of approximately 100 IU per mL of buffy coat, 20 IU per mL of plasma, 2 IU per mL of cryoprecipitate, and less than 1 IU per mL of fractions IV and V. Plasma infectivity was not eliminated by either white cell-reduction filtration or high-speed centrifugation. Approximately seven times more plasma and five times more buffy coat were needed to transmit disease by the intravenous route than by the intracerebral route.
Epidemiologic evidence of the absence in humans of disease transmission from plasma components can probably be explained by 1) the absence of significant plasma infectivity until the onset of symptomatic disease, and comparatively low levels of infectivity during the symptomatic stage of disease; 2) the reduction of infectivity during plasma processing; and 3) the need for at least five to seven times more infectious agent to transmit disease by the intravenous than intracerebral route. These and other factors probably also account for the absence of transmission after the administration of whole blood or blood components. [Absence of evidence is not evidence of absence. A mere fivefold reduction in effeciency relative to direct brain injections is highly disturbing. -- webmaster]
In previous studies of normal human blood "spiked" with scrapie-infected brain cells and of blood from mice inoculated with a human strain of transmissible spongiform encephalopathy (TSE), we found progressively lower levels of infectivity in buffy coat, plasma, and plasma Cohn fractions.1 The present study extends these observations in new experiments using the TSE mouse model, looking particularly at infectivity during the preclinical phase of disease, at the influence of processing steps on residual plasma infectivity, and at the relative efficiency of disease transmission by the intravenous rather than intracerebral route of inoculation. The assembled data provide a plausible explanation for the fact that, despite the possible presence of the infective agent in the blood of some donors who later die of Creutzfeldt-Jakob disease (CJD), no case of transmission in humans through blood or from blood donors has ever been identified. [Absence of evidence is not evidence of absence. There have been numerous known CJD donors but never a follow-up on recipients. Often too little time has elapsed for any meaningful study, given the long incubation period of this disease. -- webmaster] ...
Published estimates of the probability that a donor later dying of CJD would contaminate plasma pools of varying sizes have been based on the prevalence of CJD in the donor population and on informed guesses about the length of time that blood might be infectious before the onset of symptoms and (with data from rodent experiments) the level of infectivity that might be expected to occur.10,11
The surprising conclusion was that the risk of infection from a vial dose of protein concentrate would be such that 1 out of every 7 to 10 recipients should come down with CJD. Clearly, something was wrong with the set of assumptions leading to this conclusion, as no case of iatrogenic CJD in a blood component or product recipient has ever been identified. [Absence of evidence is not evidence of absence. -- webmaster] Our new experimental data provide at least a partial explanation for this anomaly.
Preclinical versus clinical disease; intracerebral versus parenteral infection. If, as in experimentally infected mice, plasma from humans with CJD contains little or no infectivity during the preclinical phase of disease, and if disease transmission through intravenous administration requires five to seven times more infectivity than that through intracerebral inoculation (a figure similar to the 9:1 intravenous-intracerebral ratio previously observed in mice inoculated with scrapie brain homogenate12), new sets of risk calculations can be formulated. We can now distinguish two quite different situations: one in which blood donations are made by individuals who only years later develop clinical signs, and another in which blood donations are made by individuals in the immediately preclinical or early clinical phase of CJD. The first (common) situation will involve a comparatively long duration but low level of plasma infectivity, and the second (rare) situation a much shorter duration but higher level of plasma infectivity.
If we interpret the much greater amount of plasma needed to transmit disease intravenously (7x) than intracerebrally as indicating that 7 IUs are needed to transmit disease by the intravenous route, the calculated risk of transmitting disease from a pool containing a donation from an individual in the preclinical stage of CJD varies from approximately 1 in 10 billion to less than 1 in a trillion, depending on the size of the donor pool (Table 7). Halving or doubling the estimated preclinical period changes the risk estimates by about one order of magnitude in either direction. These very low risk probabilities could by themselves explain the epidemiologic absence of transmission in recipients of recovered plasma pools.
However, in the immediate preclinical and clinical phase, in which infectivity levels are higher, the calculated risks are also higher, ranging from approximately 1 in 500,000 (10,000-donation pool) to 1 in 100 million (100,000-donation pool). [Doug McEwan continued to donate plasma long after he had developed symptoms of CJD. In fact, CJD is rarely diagnosed ante-mortem. -- webmaster.]
Reduction of infectivity by plasma processing If we cannot rely on probabilities alone to explain the apparent lack of risk in plasma recipients, we still have to take into account the reductions in infectivity associated with plasma fractionation and processing into therapeutic protein concentrates. We have shown that crude plasma fractions contain only one-tenth (or less) the amount of infectivity present in unfractionated plasma and that an additional precipitation of fraction I+III away from fraction II results in a further log loss of infectivity. A mass of emerging experimental data from other laboratories shows that virtually every processing step involving precipitation, filtration, or chromatography is associated with removals of between 1 and 6 log of infectivity, with an average reduction of 3 to 4 log (Rohwer R, Drohan W; Pettaway S; and Bailey A, unpublished, independent data). These removals would reduce the statistical risk of disease transmission to even lower levels than were estimated for unprocessed plasma from preclinical donors.
The nontransmissibility of human CJD by whole blood or its cellular components probably also results from a combination of factors. In whole-blood transfusion experiments involving 3 terminally ill donor mice and 20 recipient mice, we observed transmission in only a single animal, and similar experiments in scrapie-infected hamsters have been even less successful (Rohwer R, Drohan W: unpublished data). Moreover, whole-blood transfusions in humans have markedly declined in recent years in favor of the use of "targeted" blood components or non-blood-derived fluids, and packed RBCs and platelets probably contain little or no infectivity (our study did not examine this point, but preliminary results in a scrapie-infected hamster model indicate that both of those components have lower levels than either buffy coat or plasma (Rohwer R, Drohan W, unpublished data).
Buffy coat would pose the greatest potential risk of disease transmission, because it has the highest infectivity concentration of any blood component, but mononuclear cells are not used therapeutically at the present time and granulocyte transfusions are uncommon. Moreover, human granulocytes do not produce PrP, and thus are unlikely to be capable of transmitting infection.13 WBCs are a source of human interferon, but the only Food and Drug Administration-approved products undergo at least two chromatography steps during processing, with predicted large losses of any infectivity that might have been present in the starting material.
Rodent versus human infection None of these considerations can satisfactorily explain the apparent inability of unprocessed plasma (especially source plasma) to transmit disease, which brings us, finally, to a consideration of similarities and differences between experimentally induced disease in rodents and naturally occurring disease in humans. Similarities include the pathogenetic progression of disease after peripheral infection and the uniform finding of higher infectivity titers in central nervous system tissue than in peripheral tissue. Differences include the fact that absolute levels of infectivity in any given tissue can vary widely between natural and experimental disease, as is illustrated by the fact that infectivity in brains from patients dying of CJD averages about 40,000 IU per g of tissue,14 whereas infectivity levels were 25 to 250 times higher in the two brain pools from our mice, and the higher of the two pool titers was associated with the higher blood infectivity levels.
Furthermore, blood from naturally infected animals (sheep with scrapie and cattle with bovine spongiform encephalopathy) is not infectious, and the detection of infectivity in blood from humans with CJD has been irregular, with each of the few successes—obtained by the intracerebral inoculation of rodents—open to question on technical grounds.15 These isolations must also be judged in light of numerous failures to detect infectivity by using the two most sensitive bioassay systems: nonhuman primates14 and "humanized" transgenic mice (Prusiner S, unpublished data, June 1999).
For all of these reasons, we believe that our rodent model almost surely overestimates the levels of infectivity present in the blood of humans with naturally occurring CJD and that, although unquantified, the actual risk of such blood to contain sufficient infectivity to transmit disease when administered intravenously to another human must be very close to zero.
Donor pool size and apparent dilution-related reduction in transmission risk We have previously argued that an IU, which by definition is capable of transmitting infection, should retain that capability whether contained in the plasma from a pool of 10 or 10 million donations; that is, it will never be "diluted-out."11 This reasoning assumed that infectivity would be transmitted in the same way it was assayed—that is, by intracerebral inoculation; however, the need for more infectivity to transmit disease when the inoculation is given by the intravenous rather than the intracerebral route significantly affects the calculation.
At some dilution, the amount of infectivity contained in the volume inoculated into a single animal, although insufficient to transmit disease by the intravenous route, should still be capable of transmitting disease by the intra-cerebral route. This should occur whether parenteral transmission requires multiple IUs, or merely enough "excess" IUs to surmount peripheral clearance mechanisms. The predicted disappearance of infectivity in specimens inoculated intravenously is not inconsistent with the argument that an IU will remain infectious no matter how great the dilution. It makes no assumptions about the physical state of the IU; it only says that more infectivity is required to transmit disease by the intravenous route than by the intracerebral route. Assuming that levels of human plasma infectivity are as low as or lower than those in mice, a practical consequence is that larger plasma pools would be predicted to reduce the risk of CJD transmission.
WBC-reduction filtration and high-speed centrifugation The failure of filtration or high-speed centrifugation to eliminate plasma infectivity has both practical and theoretical implications. The much higher levels of infectivity in buffy coat than in plasma in endogenously infected pools of blood, as well as the similar distribution of infectivity in normal human blood that had been "spiked" with intact infectious brain cells, strongly suggests that the origin of blood infectivity is to be found in the WBC. Although WBC-reduction filtration of whole blood to reduce the number of WBCs admixed in packed RBCs is a plausible strategy to decontaminate the RBCs, WBC-reduction filtration of plasma to eliminate residual infectivity does not appear to be useful.
The failure of WBC-reduction to reduce infectivity indicates that intact cells are not the source of plasma infectivity. The failure of high-speed centrifugation to eliminate infectivity in plasma that contained no detectable membranous structures also indicates that fragmented membranes from WBCs and/or platelets in the plasma are not the only source of infectivity. Therefore, if plasma infectivity originates in WBCs, it must be partly in the form of very small, unsedimentable particles, molecular aggregates, or individual molecules in the cytoplasm of disrupted cells, or released from their membranes. Such nonsedimentable, non-membrane-associated particles that have not been subjected to artefact-inducing extraction procedures could prove useful in experimental efforts to measure the size and explore the nature of the smallest naturally occurring molecular species capable of transmitting disease.
We believe that the experiments reported here and in our previous article1 have culled about as much information from the TSE-infected mouse model as can be usefully applied to the human situation. It will be important to learn if other experimental models, especially CJD-infected nonhuman primates, yield data that support the conclusions drawn from the mouse model and validate our explanation of why, despite the possibility that some blood donor pools may indeed be "tainted" with infectivity, no sporadic, familial, or iatrogenic CJD has ever been transmitted to recipients of blood or blood components or products. Additional experiments, already underway, will be needed to assess the risk, if any, from the blood of patients with new variant CJD.
1. Brown P, Rohwer RG, Dunstan BC, et al. The distribution of infectivity in blood components and plasma derivatives in experimental models of transmissible spongiform encephalopathy. Transfusion 1998;38:810-6. 2. Tateishi J, Ohta AM, Koga M, et al. Transmission of chronic spongiform encephalopathy with kuru plaques from humans to small rodents. Ann Neurol 1979;5:581-4. 3. Vandersande J. Current approaches to the preparation of plasma fractions. In: Goldstein J, ed. Biotechnology of blood. Boston: Butterworth-Heinemann, 1991:165-76. 4. Oncley JL, Melin M, Richert DA, et al. The separation of antibodies, isoagglutinins, prothrombin, plasminogen and beta lipoproteins into sub-fractions of human plasma. J Am Chem Soc 1949;71:541-50. 5. Monari L, Chen SG, Brown P, et al. Fatal familial insomnia and familial Creutzfeldt-Jakob disease: different prion proteins determined by a DNA polymorphism. Proc Natl Acad Sci U S A 1994;91:2839-42. 6. Korth C, Stierli B, Streit P, et al. Prion (PrPSc)-specific epitope defined by a monoclonal antibody. Nature 1997;390:74-7. 7. Kascsak RJ, Fersko R, Pulgiano D, et al. Immunodiagnosis of prion disease. Immunol Invest 1997;26:259-68. 8. Peto S. A dose response equation for the invasion of micro-organisms. Biometrics 1953;9:320-35. 9. Ridout MS, Fenlon JS, Hughes PR. A generalized one-hit model for bioassays of insect viruses. Biometrics 1993;49:1136-41. 10. Lynch TJ, Weinstein MJ, Tankersley DL, et al. Considerations of pool size in the manufacture of plasma derivatives. Transfusion 1996;36:770-5. 11. Brown P. Donor pool size and the risk of blood-borne Creutzfeldt-Jakob disease. Transfusion 1998;38:312-5. 12. Kimberlin RH, Walker CA. Pathogenesis of experimental scrapie. In: Bock T, Marsh J, eds. Novel infectious agents and the central nervous system. Ciba Foundation Symposium 135. Chichester, UK: John Wiley & Sons, 1988:37-54. 13. Dodelet VC, Cashman NR. Prion protein expression in human leukocyte differentiation. Blood 1998;91:1556-61.[Abstract/Full Text] 14. Brown P, Gibbs CJ Jr, Rodgers-Johnson P, et al. Human spongiform encephalopathy: the National Institutes of Health series of 300 cases of experimentally transmitted disease. Ann Neurol 1994;35:513-29. 15. Brown P. Can Creutzfeldt-Jakob disease be transmitted by transfusion? Curr Opin Hematol 1995;2:472-7.
Br J Haematol 1999 Dec;107(4):804-814 Barclay GR, Hope J, Birkett CR, Turner ML Edinburgh Regional Blood Transfusion Centre, SNBTS, Edinburgh, and.Leucocyte subpopulations from normally healthy individuals were identified by recognized combinations of fluorochrome-conjugated antibodies to CD markers and stained by different monoclonal antibodies (MAb) to normal cellular prion protein (PrPC), including the 3F4 MAb.
Cell preparations were examined by three-colour flow cytometry. All mononuclear leucocyte subpopulations and platelets expressed PrPC, but polymorphonuclear leucocytes and red blood cells expressed little or no PrPC. The amounts of PrPC expressed by the different cells were calculated by comparison to bead standards.
Mononuclear leucocytes expressed 3000-4000 molecules of antibody-reactive PrPC per cell. Resting platelets expressed around 1400 molecules of PrPC per cell, whereas activated platelets expressed around 4800 molecules of PrPC per cell.
Extrapolation of these values to the amounts of the various cells in whole blood showed that platelet PrPC accounted for at least 96% of cell-expressed PrPC in blood.
The PrPC on mononuclear cells and platelets was sensitive to enzymatic treatment of cells by proteinase k and phosphatidylinositol-specific phospholipase C. Certain anti-PrPC MAbs which showed equivalent intensity of staining to MAb 3F4 on fresh cells showed relative reductions of staining compared to MAb 3F4 on stored cells, indicating possible structural alterations of PrPC under these conditions.
Dev Biol Stand 1999;100:103-18 Asher DM Office of Vaccine Research and Review, CBER/USFDA, Rockville, MDRegulatory agencies responsible for protecting public health must be concerned with reducing or preventing opportunities for exposure of humans and animals to the agents of transmissible spongiform encephalopathies (TSEs), especially bovine spongiform encephalopathy and Creutzfeldt-Jakob disease. The United States Food and Drug Administration (FDA) has taken precautionary actions to assure that regulated products are free of such infectious agents, from both animal and human sources, including the issuing of a regulation and a number of guidance documents.
With regard to TSEs, the materials of greatest concern to FDA's Center for Biologics Evaluation and Research have been bovine gelatin, tallow derivatives and serum, as well as human-derived products and excipients including blood, blood components and plasma derivatives. A number of newer issues regarding TSEs now confront agencies responsible for protecting public health. It would be of great help to have standard reference materials available to assist in the diagnosis of the diseases and to detect the infectious agents.
Monday, December 27, 1999 By Katy The Daily Camera Boulder ColoradoOpinion (webmaster): Here is an amusing follow-up on America's counterpart to John Gummer. The CDC administrator, who has never worked on TSEs, wouldn't hesitate to eat venison from ground zero in NE Colorodo saying, what else, that he would eat it himself a 'healthy' deer in a New York minute.
The catch is, of course, no one has the slightest idea which ones are healthy. And by the time 200 are ground up at a processing facility (a typical batch), you can be confident that your deer will be mixed in with 10 that had near-clinical CWD.
Gambetti, a working researcher, has more sense, saying he'd avoid eating venison. "Why should I? I can eat something else."
True enough professor, but that won't sell a lot of out-of-state game tags. Miller's fish and game department draws 51% of its total annual budget from these. It is amazing that they have the gall to continue with this stupidity in the face of what is happening in England. The precautionary principle and public health have never been a priority for American agencies either. Is peddling game tags really part of the CDC mission statement?
"The story is right out of the X-Files. Three people died horrible deaths after eating venison. Their brains slowly filled with tiny holes and they eventually succumbed to dementia. Recent news accounts made a chilling suggestion chronic wasting disease, previously found only in deer and elk, might be able to jump into people and cause the invariably fatal brain disease Creutzfeldt-Jakob.
Researchers say the story's fiction. Probably.
"We've been investigating that and so far the evidence is an all-clear sign to us," said Lawrence Schonberger, a medical epidemiologist for the Centers for Disease Control. "If you enjoy hunting, I wouldn't lose sleep over this."
Pierluigi Gambetti, a professor of pathology and director of the National Prion Disease Pathology Surveillance Center at Case Western University in Cleveland, is slightly less confident. "So far, we don't have anything to suggest anything abnormal going on, but we do have to expand our surveillance," Gambetti said. "We really can't know yet one way or another."
Colorado wildlife managers caution hunters to wear gloves when dressing their deer, "just in case." They're more concerned, however, about the disease's effect on the state's deer herd than the remote possibility it may jump to people. In Larimer County, about one in every 20 mule deer has chronic wasting disease, and with Colorado's mule deer populations mysteriously declining, that's enough to cause some worry. Last week, officials with the Division of Wildlife decided to experiment with deer management in the northeastern part of the state to see if they can cut down the incidence of chronic wasting disease [by slaughtering more deer by issuing large numbers of hunting tags to recreational hunters. -- webmaster].
"It really has not changed, in distribution or prevalence over last few years," said Mike Miller, the state veterinarian. "It's slow moving but pretty insidious, and we're not waiting for a crisis." Chronic wasting disease apparently occurs nowhere on the planet but northern Colorado and southern Wyoming, Miller said. [Plus game farms in numerous states. -- webmaster]
According to state surveys, 4 percent to 5 percent of the deer in northeastern Colorado have the fatal disease, and less than 1 percent of the elk. Chronic wasting disease is strikingly similar to other infectious brain diseases, including mad cow disease (bovine spongiform encephalopathy, BSE) and the human Creutzfeldt-Jacob disease. All are so-called prion diseases, caused by runaway proteins that behave more like evangelists than the workhorses of cells. Prion proteins can spontaneously mutate, changing into a dangerous new shape that "converts" other normal prion proteins into the aberrant form. New converts convert others, eventually clogging and killing cells in various parts of the brain.
And some prions can apparently jump from one species to another.
Last week, researchers reported the most decisive evidence to date that people have caught Creutzfeldt-Jakob disease by eating the meat of mad cows. In the last few years, more than 50 people in the United Kingdom have died of a new variant of Creutzfeldt-Jakob disease, probably transmitted through bad beef. The cause of the recent surge of concern about chronic wasting disease in the United States is the appearance of Creutzfeldt-Jacob disease in four young people since 1996.
The disease kills about 250 people each year in the United States, but it typically strikes people in their 50s, 60s and 70s. It's unusual to find Creutzfeldt-Jacob disease in young people, the Centers for Disease Control's Schonberger said. "That's one of the big clues that set people in the UK to searching for a possible connection to mad cow disease, when they got people in their teens and 20s getting CJD," he said. The new variant of Creutzfeldt-Jacob disease hasn't yet turned up in the United States the four recent cases of the disease in young people in this country represent the more common form of the disease.
Researchers did worry, however, when they discovered that three of the four victims had eaten venison fairly regularly. Schonberger called the link a red herring because there are so many hunters in this country, it's probably just a statistical coincidence. He also pointed out that the victims ate deer shot in Oklahoma, Utah and Maine, states where chronic wasting disease has never been seen.
Schonberger said he wouldn't hesitate to eat the meat of a healthy deer. [There is no practical way of telling whether a given deer is healthy -- webmaster.]
"Look, even if you're in (northeastern Colorado), the majority of animals are not going to be infected," he said. "If it is, some of its tissue might not be infected, or the titer of infectious material might not be great enough to pass on. "And even if it was a big chunk of highly infectious tissue, we don't even know if the disease can be passed to humans," he said. "I can't tell you with certainty that all these unusual possibilities couldn't combine, but it's unlikely."
Gambetti, however, said he'd avoid eating venison. "Why should I? I can eat something else," he said. "But that's not because I really think there is great danger," he added. "I just think the whole issue of prion disease in the United States, both in animals and humans, has to be confronted seriously. We really have to do more."
The obvious experiments can't be done, ethically, of course. No one would suggest injecting brain tissue from a sick deer into humans. Gambetti said that highly efficient surveillance and tissue testing would help researchers nail down the link, if any, between chronic wasting disease and Creutzfeldt-Jacob disease. If researchers could get tissue samples and histories from more than 50 percent of the people that die of Creutzfeldt-Jacob disease in this country, he suspects we'd have an answer in a few years.
John Pape, an epidemiologist with the Colorado Department of Public Health and the Environment, said the state received a bit of money from the Centers for Disease Control earlier this month, to begin Creutzfeldt-Jacob disease surveillance. He said it'll be difficult to study the relationship between the human and deer diseases, however, because the human disease is so rare. About 250 people in the United States die of Creutzfeldt-Jacob every year. More than 42,000 die of breast cancer. "It's hard to design a study to find that needle-in-a-haystack case," Pape said.
In Colorado, taxidermists, game dressers and hunters the people most likely to come into contact with infected deer tissue seem no more likely to get Creutzfeldt-Jacob disease than anyone else, Pape said. Nevertheless, until more research is done, he said he supports the Division of Wildlife's new deer management policies and handling precautions.
Earlier this month, division staff decided to offer extra hunting permits in northeastern Colorado next year. The idea is to keep deer populations down in that area to see if a chronic wasting disease will spread less easily among animals do to a less dense population, said Todd Malmsbury, spokesman for the Division of Wildlife Wildlife managers will also cull diseased or suspected diseased animals from an area north of Fort Collins this spring.
The agency is also considering allowing private landowners to immediately kill any diseased animals they see. "If there's any doubt about the health of an animal, you remove it from the population," Miller said. "The risk is that you remove an animal that's just having a bad day," he acknowledged. "But in this situation, that's probably better than the alternative."
Mon, 3 Jan 2000 London Sunday Times Jonathan Leake and Wayne BodkinComment (Lynettte Dumble, Australian CJD expert):
British and French, skullduggery which has effectively "globalized" mad cow disease. I say "notably British and French", because to quote myself :
"Britain was not alone in the cover-up of the BSE epidemic. In September, 1996, the French newspaper Liberation(*) revealed that a memorandum from French official Gilbert Castille had suggested back in 1990 that Britain ought to be asked not to publish its research results, saying OIT would be better to minimize BSE by practicing disinformation. In fact, rather than ganging up on Britain, Brussels via Guy Legras, head of the European Commission's agricultural directorate, warned of the financial repercussions from a beef panic and hushed news of the BSE situation".
*Hooper, John. Britain evaded BSE checks for Europe. The Guardian Weekly September 1, 1996, page 9. *Radford, Tim. 700,000 BSE cattle 'fed to humans'. The Guardian Weekly September 8, 1996, page 9. *Bates, Stephen. EU hushed up BSE scandal for five years. The Guardian Weekly September 8, 1996, page 1.ONE of France's leading scientific advisers on BSE has admitted that her country has thousands of undiagnosed cases, and infected animals could have entered the food chain.
Professor Jeanne Brugère-Picoux, of the Agence Française pour la Securité Sanitaire et Alimentaire - the authority that has advised the French government that British beef is still dangerous - said that although France has officially registered 75 cases of BSE in the past 10 years, she believed the real figure to be "far higher than that".
BSE-infected carcasses could have entered Britain. More than 12,000 tons were exported to Britain in 1996 and 8,000 in 1997, the last year for which figures are available. More than 3,000 live French cattle have been imported to Britain since 1996.
Brugère-Picoux's admission comes as legal wrangles continue over France's continued refusal to lift its ban on British beef. The French government is expected to launch a countersuit against the European commission in the European Court of Justice tomorrow.
Although Brugère-Picoux backs the decision to exclude British beef, she is increasingly alarmed by events at home. France's third case of variant CJD - the type linked to eating BSE-infected beef, which has killed 48 people in Britain - was recently confirmed in a 36-year-old Parisian woman.
Although the victim had never been to Britain, the French health ministry has insisted that she caught the disease by eating infected British beef or French animals that had eaten British feed. It refused to consider that France may have its own BSE problem.
A court case last month, however, suggested otherwise. Hubert André, a farmer from St Dié in eastern France, was given a two-month suspended prison sentence and £4,000 fine for illegally killing a cow diagnosed by a local vet as having BSE. Under French regulations, the entire herd should have been destroyed immediately. André's animals survive, despite his conviction.
Brugère-Picoux believes the policy of destroying herds is scaring off French farmers from declaring cases. "The first inkling they have that something is not right, off goes the animal to the abattoir. It then enters the food chain,"she said.
Another government adviser dismissed French agriculture ministry claims that they "take no risks whatsoever". Professor Noëlle Bons told a seminar organised by the World Health Organisation: "In France people are still eating beef brain and bone marrow on bread." Both experts are calling for a new European agency to carry out random BSE testing.
Thu, 23 Dec 1999 correspondence with Belgian journalist"A national TV drew my attention to a reference supposedly in yesterday's (Dec 22, 1999) Le Monde alleging that Cordelia Selwyn Gummer (she of the famous picture in which, her father the Environment Minsiter under the last Conservative government during the BSE crisis, is seen in 1997 forcing her at age 4 to eat a beefbuger).... has now contracted the nvCJD."
French correspondent explains: "It's only a joke, in Le Monde. For French poeple it's a kind of "humour Britannique". Below is a translation of the Le Monde article:
Le Monde daté du mercredi 22 décembre 1999 from our corresponder in London Patrice Claude
At the moment, girl Cordelia Gummer, 13, is all right. Her father John must wonder, however. Nine years ago, this well-intentionned daddy was ministry of Agriculture, in John Major's government. He was so sure, at that time, that "mad cow disease" could not involve humans that he had intended, in order to confort the people, to share, live on TV, a huge hambrger with his daughter, 4 years old at that time. The image remained, the certainties did not.Pour l'instant, la petite Cordelia Gummer, treize ans, va bien. Son père John doit pourtant se poser des questions. Il y a neuf ans, ce papa bien intentionné était ministre de l'agriculture du gouvernement de John Major. Il était alors si sûr que la maladie de la « vache folle » ne pouvait affecter l'homme qu'il avait entrepris, pour rassurer le public, de partager, en direct à la télévision, un énorme hamburger avec sa fille alors âgée de quatre ans. L'image est restée, les certitudes se sont envolées.Stepehn Churchill, first British victim of the prion, died in may 1995 at the age of 19. Ten more months were necessary before the government admits, in the House of Commons, march 1996, there might be a "link" betwenn BSE and vCJD. Today, thanks to the numerous scientific testimonies heard during the 21 months of public Enquiry, Lord Phillips declares in a naive way "we shall consider the important scientific evidences that suggest the bovine and human diseases are linked".Stephen Churchill, première victime britannique du prion, est mort en mai 1995 à l'âge de dix-neuf ans. Il faudra attendre dix mois de plus pour que le gouvernement admette devant le Parlement, en mars 1996, qu'il pourrait bien exister « un lien » entre l'encéphalopathie spongiforme bovine (ESB) et la nouvelle forme de la maladie mortelle de Creutzfeldt-Jakob (MCJ). Aujourd'hui, au vu des multiples témoignages scientifiques entendus durant vingt et un mois d'enquête publique, Lord Phillips déclare candidement : « Nous allons notamment considérer les preuves scientifiques importantes qui nous suggèrent que les maladies bovines et humaines sont liées.After presiding the auditions, this high judge in the Court of Lords of Justice must give his final report to the government on the 31st of March 2000. The Inquiry itself came to an end on the 17th of Dec. Afterwards, everything in the article concerns the final statement of Lord Phillips, and does not give further information on vCJD cases.Après avoir présidé les auditions, ce haut magistrat de la Cour des Lords de justice du royaume doit rendre son rapport final au gouvernement le 31 mars 2000. L'enquête proprement dite a pris fin vendredi 17 décembre. Au total, 860 témoignages de responsables politiques, hauts fonctionnaires, experts et membres des familles des victimes ont été recueillis. Il s'agit avant tout d'établir les responsabilités publiques, politiques et éventuellement pénales de la gestion désastreuse de ce qu'on a appelé la « crise de la vache folle ». Plusieurs ministres conservateurs, à commencer par Margaret Thatcher et John Major, qui se sont toujours montrés rétifs à toute mesure de précaution, pourraient avoir à répondre de leur conduite. DES LOBBIES ENCORE ACTIFS Lord Phillips a rappelé que sa commission n'était pas à proprement parler de nature scientifique. Pourtant, a-t-il souligné, une chose est sûre : « Lorsque nous avons commencé nos travaux en mars 1998, vingt-quatre familles avaient perdu un des leurs du fait de cette nouvelle variante de la maladie de Creutzfeldt-Jakob. Aujourd'hui, le bilan a exactement doublé, et nul ne peut dire si ces quarante-huit victimes britanniques représentent seulement la partie émergée de l'iceberg. » Le professeur Peter Smith, qui préside le comité-conseil du gouvernement sur la maladie humaine, ne cachait pas, jeudi, son ignorance en la matière. « Si la période moyenne d'incubation est de dix ans, disait-il, alors nous sommes largement entrés dans l'épidémie, et elle pourrait être relativement limitée. Mais, si elle est de vingt ans, nous pourrions avoir à faire face à un problème beaucoup plus sérieux. » Mais, le jour même où ces propos peu rassurants étaient reproduits dans la presse, le gouvernement annonçait la levée de l'interdiction décidée il y a deux ans des ventes de boeuf à l'os. Coïncidence « de fort mauvais goût », notait Roger Tomkins, père d'une des victimes. Tony Blair cédait ainsi à la forte pression du lobby des éleveurs mais aussi à celle des consommateurs : dans les supermarchés, ce fut la ruée...
Thu, Dec 30, 1999 By Geoff Meade, European Editor, PA News in BrusselsLegal action against France for refusing to lift the ban on British beef will be launched on Monday, a European Commission spokesman said today. The move was decided after France sent a letter to the commission making a fresh attempt to justify the continuing trade blockade and offering no end to the dispute through diplomatic channels. The French also stepped up the trade war by vowing to launch their own legal action against the commission for allegedly failing to do enough to protect consumer health.
The letter came just hours before the expiry of the deadline for a response from Paris to the threat of legal action. But its contents failed to convince EU officials the ban was justified on consumer health grounds. "We consider there is nothing spectacularly new in the arguments put forward by France. Therefore we have decided to go to court," said the commission spokesman.
Food safety commissioner David Byrne will now press on with formal proceedings in the European Court of Justice on Monday. The process starts with the lodging of legal commission papers with the European Court secretariat in Luxembourg. The documents state that France is persisting in defying EU law by refusing to trade in beef from Britain. But it will be months before the case reaches the courtroom, possibly putting France in the dock during its six-month EU presidency, which begins on July 1 next year.
There was little expectation that today's letter would solve the Anglo-French crisis. Paris had been given until 11pm UK time tonight to respond to a "reasoned opinion" from Brussels setting out the grounds for going ahead with court action. The French are legally bound by a vote of EU governments to resume taking British beef imports from last August 1.
That vote, in which France abstained, came three and a half years after the commission imposed a worldwide British beef export ban in response to consumer fears about the spread of mad cow disease. That seemed to end the crisis for British beef farmers, but the newly-formed French Food Safety Agency challenged the scientific evidence about the safety of British beef, and the French government went back on the agreement to open its markets to beef from the UK.
Formal infringement proceedings against France were launched on November 16 after the failure of three months of diplomatic efforts to get the beef ban lifted. Since then the French government has won two delays in the deadline for triggering the EU's ultimate - and most time-consuming - sanction against a member state which refuses to apply the law. Mr Byrne still hoped that behind-the-scenes talks would resolve the crisis without plunging the EU into a protracted legal wrangle with a major member state.
But even a clean bill of health for British beef from independent scientific experts - headed by a Frenchman - failed to bring France into line. Now commission patience has finally run out with repeated requests from France for more time to consult various food and consumer health departments and the French Food Safety Agency which triggered the whole crisis in September. Today's letter offered no new evidence about the safety of British beef, and surprised EU officials by announcing the intention to take the commission to court.
The French grounds are that by ignoring French warnings about the alleged continuing health risk from British beef, the commission is failing in its legal duty to protect consumer health. Mr Byrne has been accused of unnecessary reluctance to begin formal legal proceedings against France. The Commissioner himself insisted for months that a diplomatic solution was best, but his critics said that would not prevent the start of a legal process which will in any case take months if not years.
Meanwhile Mr Byrne must also decide soon whether to launch similar legal action against Germany, the only other EU country still refusing to accept British beef. Unlike France, which claims the scientific evidence still points to a human health risk from British beef, the Germans say there are bureaucratic hold-ups surrounding parliamentary ratification of the EU rule restoring the British beef export trade.
But serious concerns over the health of British beef have been expressed by some German regional authorities which have power to decide for themselves whether to accept UK imports. The commission has already threatened that Germany will join France in the European Court dock if it is stalling.
Colin Breed, Liberal Democrat agriculture spokesman, condemned the French decision to launch their own legal action against the commission. "The French ought to put their own house in order. There is a rising incidence of BSE in France. "France should be prepared to allow its own beef industry to be inspected by their own food and safety agency using exactly the same criteria applied to British beef," he said.
Lancet Volume 354, Number 9191 13 November 1999 Johannes Pammer, Angelika Suchy, Michael Rendl, Erwin TschachlerHighlights:
Routes of transmission of bovine spongiform encephalopathy have not yet been determined. We show that bovine squamous epithelia of the skin and upper gastrointestinal tract express Prpc, suggesting that these epithelia may be a target for prion entry and replication....The hypothesis that the conversion of PrPc to PrPSc could start at the site at which prions meet PrPc for the first time prompted us to study the expression of the latter in the skin and the upper gastrointestinal mucosa of cows.
We immunostained formalin-fixed paraffin-embedded tissue samples of skin (snout, flank, ear, udder), tongue, oesophagus, and ulcerating skin (carpus, udder, snout) and squamous epithelia (tongue, oesophagus) of six animals without BSE, and reticulum, rumen, and omasum of another three animals with an anti-PrP monoclonal antibody (6H4, Prionics, Zürich, Switzerland).
In normal skin, staining for PrPc was seen on basal keratinocytes. On the snout, and to lesser degree on the tongue and the oesophagus, suprabasal keratinocytes were also stained. Upregulation of PrPc expression was seen in acanthotic epidermis adjacent to skin ulcers. Reactivity of peripheral nerves of the dermis with the anti-PrPc reagent served as internal positive control. Incubation of consecutive tissue sections with an isotype-matched antibody (IgG1, Coulter, Hialeah, FL, USA) gave no detectable staining in epithelial cells of the skin and upper gastrointestinal tract and peripheral nerves. By contrast, staining of the fore-stomach with the control reagent showed a distinct cytoplasmic reactivity which was indistinguishable from the anti-PrPc staining . Therefore epithelial cells of the fore-stomach were considered negative for PrPc.
We analysed cultured bovine keratinocytes derived from the snout or ear by Western blotting. In five experiments, we found that bovine keratinocytes constitutively expressed PrPc in vitro. Lysates of brain tissue served as positive control. Deglycosylation of keratinocyte-derived and brain-derived PrPc showed a core protein of the expected size, ~25 kD. PrPc is expressed constitutively by bovine keratinocytes in tissue culture.
Our data show that squamous epithelial cells in the upper gastrointestinal tract and in the skin of cows express PrPc and that its expression is upregulated adjacent to skin ulcerations. It is noteworthy that skin ulcerations and wounds have been suggested to play a part in the transmission of kuru and transmissible mink encephalopathy. Epithelial PrPc might serve as the first target for prions, and therefore epithelia could function as their port of entry.
Nature 402, 849 (1999) David DicksonOne of the key government officials in Britain's recent crisis over bovine spongiform encephalopathy (BSE) has been forced out of his job. The move came days after the completion of an official inquiry that is expected to be highly critical of the way in which the crisis was handled.
The Ministry of Agriculture, Fisheries and Food (MAFF) announced on Monday the departure of Richard Packer, its top civil servant. Packer was at the centre of events in March 1996 surrounding the announcement of evidence that BSE might be responsible for a new form of Creutzfeldt-Jakob Disease (CJD) in humans (see Nature 380, 273; 1996).
Ironically, Packer's departure coincides with new evidence -- published this week in the Proceedings of the National Academy of Sciences by a team of US and UK researchers -- strengthening the likelihood that new-variant CJD is caused by the same agent as that responsible for BSE in cattle...
Packer -- who describes his recreation in Who's Who as "living intensely" -- is widely known as a highly skilful, respected and, in some quarters, feared civil servant. He has a reputation for staunchly defending the interests of his ministry (and Britain's agricultural community), and standing up to ministers when he felt this necessary.
Unlike most of his predecessors, he did not graduate from Oxford or Cambridge, but joined the ministry after postgraduate studies in chemical engineering at the University of Manchester in 1967. His departure is being described by government officials as a reflection of their desire to 'modernize' the civil service, bringing it more closely in line with the strategic priorities of the Labour government.
But some say that Packer's position has been weakened by the evidence that has emerged over the past two years of the BSE inquiry, headed by Lord Justice Phillips. Questioning Packer on his earlier evidence during a cross-examination this month, for example, Phillips suggested that conclusions about a possible CJD/BSE link reached by the Spongiform Encephalitis Advisory Committee in February 1996 had not been treated with sufficient urgency. [That is, Parker gave beef sales a higher priority than human health. Ten deaths from nvCJD over a period of years were announced as a cluster in March 1996; Parker knew years earlier what was happening. -- webmaster.]
However, Phillips also expressed concern that, when it become clear that the news had major implications both for public health and for the UK beef industry, "practical decisions were taken in a great rush".
Packer has strongly defended his role in the crisis. He is reported in The Times to have told colleagues that he was only a "bit player", and that "the inquiry will show that my actions have been close to exemplary".
His departure after seven years in the top post at MAFF is likely to have major implications for the future of the ministry itself. Packer has long been a strong opponent of attempts to locate responsibility for food safety in a separate government department. Such a move, he feared, could reduce what was until recently one of the most powerful ministries in Whitehall to little more than a Department of Rural Affairs. His departure makes that more likely.