Document Directory

19 May 01 - CJD - Controlling New Prion Diseases
18 May 01 - CJD - Politicians blamed as BSE spreads in France
18 May 01 - CJD - French bse study condemns British animal feed trade
17 May 01 - CJD - PNAS - prion disease incubation period in mice
17 May 01 - CJD - Ask the Pharmacist
17 May 01 - CJD - Study: Up to 300 French vCJD Cases in Next 60 Years
17 May 01 - CJD - BSE: Risk assessments for Costa Rica, Kenya, Slovenia and Romania
17 May 01 - CJD - Tests find deficiencies in measures designed to avoid Mad Cow disease
17 May 01 - CJD - 1/3 of state's cattle-feed producers fail some inspections
17 May 01 - CJD - Mother of CJD victim tells of fears for family
17 May 01 - CJD - How safe is our meat?



19 May 01 - CJD - Controlling New Prion Diseases

Raymond P. Roos, M.D.

New England Journal of Medicine--Saturday 19 May 2001


Like the murrain -- the fifth plague in the biblical story of Exodus, which targeted cattle -- a new prion disease called Bovine Spongiform Encephalopathy (BSE) has had a devastating impact. Millions of cattle have been destroyed and billions of dollars spent throughout the world. The socioeconomic, political, and public health toll has been staggering.

In this issue of the Journal, Prusiner (1) describes prions, the infectious proteins that are responsible for this group of diseases. He also proposes that abnormally processed proteins such as prions cause other neurodegenerative diseases. Prions have remarkable properties for a pathogen: transmissibility with a very long incubation period (e.g., an average of five years for BSE in cows and possibly more than a decade for new variant Creutzfeldt-Jakob disease, a form of BSE transmitted to humans), absence of immunogenicity, and resistance to inactivation and to protease digestion. The unusual properties of prions have posed challenges for surveillance and control.

BSE originated in the United Kingdom in the 1980s, probably from cattle feed that was initially contaminated with tissue from sheep infected with scrapie, a prion disease in sheep and goats. (2,3) Remnants of slaughtered cattle that had fed on the infected material were then used as a source for feed, resulting in the continual recycling of material from BSE-infected cattle back into feed. These conditions allowed the prion to adapt to cattle.

Changes in rendering procedures (in which the carcass is processed after the removal of readily consumable parts) may have allowed the maintenance of sufficiently high prion levels for efficient transmission. Although the number of cases of BSE in cattle has decreased substantially over time in the United Kingdom (from a high of over 37,000 cases in 1992 to 1537 in 2000), cases have recently been identified in other countries, in part through the use of immunologic screening tests. These countries include Germany, Ireland, and France (with 7 cases, 145 cases, and 161 cases, respectively, in 2000). (4)

Initially, there was a false sense of security with respect to the risk of the transmission of BSE to humans. Epidemiologic studies had found no link between scrapie and the sporadic form of Creutzfeldt-Jakob disease (the most common prion disease in humans), which appears to occur spontaneously throughout the world. It is now apparent that the properties of the BSE agent are distinct from those of other prions. Approximately 100 cases of new variant Creutzfeldt-Jakob disease, a new disease that causes dementia and has distinctive neuropathological features, have been reported since 1996. (3,5) All these cases have been in the United Kingdom, except for two confirmed and one probable case in France and one confirmed case in Ireland.

There is compelling evidence of the transmission of new variant Creutzfeldt-Jakob disease to humans, probably through the consumption of meat contaminated with BSE-infected central nervous system tissue.

To date, there is no evidence of BSE or new variant Creutzfeldt-Jakob disease in the United States. To limit the spread of BSE, in 1989 the U.S. Department of Agriculture banned the importation of live ruminants (cud-chewing animals, including cows and sheep) and most ruminant products from countries with known cases of BSE. In 1997, the ban was extended to apply to countries deemed to have inadequate animal-import restrictions or surveillance, which included all the European countries. The live-ruminant ban has been successful; the relatively small number of sheep and cattle imported before the ban have virtually all been accounted for.

Some biomedical products that contain or have been exposed to ruminant-derived materials from countries on this BSE list are still in use in the United States, including some vaccines that contain products such as fetal-calf serum. However, the risk of transmission of prions from vaccines seems remote for several reasons. The oral and parenteral routes of vaccination are relatively inefficient for transmission. The bovine-derived material is present in extremely small amounts, is unlikely to have been derived from an infected cow, and comes from tissues that are unlikely to be very infectious with respect to BSE (e.g., blood). Finally, epidemiologic data suggest that new variant Creutzfeldt-Jakob disease is not transmitted through vaccination.

Despite the presumed safety of vaccines, the Food and Drug Administration (FDA) has requested that manufacturers use bovine-derived products only from countries that are not on the BSE list. To avoid the perception of a risk of prion disease from vaccination, these measures must be enforced. An additional concern (6) involves the relative lack of regulation of dietary supplements with tissue or gland extracts (e.g., from the pituitary) containing bovine central nervous system tissue that may come from countries on the BSE list. New laws are needed to control the importation of these products.

The Department of Agriculture has had a screening program for BSE since 1990. Neuropathological examinations have been performed on more than 12,000 U.S. cattle that exhibited neurologic signs before slaughter, such as difficulty walking ("downer" cattle). All the results were negative. Screening should be extended to include a much larger proportion of the more than 150,000 downer cattle in the United States each year, including cattle that die before they are slaughtered. Some asymptomatic animals older than four years of age should also be tested, since prions accumulate over time in the infected host and are therefore easier to detect in older animals.

Screening should be performed with immunologic tests similar to those used in Europe (e.g., an enzyme-linked immunosorbent assay or Western blot assay for the detection of protease-resistant prion protein). (7) The use of such tests would lower the cost of screening and permit rapid, large-scale analyses. Such tests, however, had not been approved for use in the United States as of April 2001.

The Department of Agriculture should establish and enforce guidelines for the slaughter of cattle in order to decrease the chance of contamination of meat with infected central nervous system tissue. These guidelines should address methods of killing, early removal of the spinal cord from the carcass, and waste disposal (e.g., the use of chemicals to inactivate prions as well as to decrease the huge volume of potentially infected waste).

To limit widespread transmission of BSE from contaminated feed, as occurred in the United Kingdom, the FDA in 1997 banned most mammalian proteins from ruminant feed. This ban is not sufficiently comprehensive: blood, gelatin, and "plate waste" (i.e., leftover food from restaurants) should not be exempted, as they currently are. The FDA inspects facilities such as feed mills and rendering plants to confirm compliance with the ban and to ensure that cattle feed is not commingled with rendered material from cattle (which is still used as feed for nonruminants, such as chickens and pigs). Approximately 25 percent of these facilities initially failed inspection, although later inspections showed much better compliance. To provide greater safety and eliminate the need for inspections, all rendered material from cows should be banned from use in any feed.

The emergence of new variant Creutzfeldt-Jakob disease in the United Kingdom led to enhanced surveillance for human prion diseases by the Centers for Disease Control and Prevention (CDC). (8) A registry of human prion disease has been established with the use of data on causes of death, such as information from death certificates. In collaboration with Case Western Reserve University, in Cleveland, the CDC established a national surveillance center, which performs neuropathological examinations and immunologic tests for prion protein in brain tissue.

In addition, a cerebrospinal fluid assay is performed for 14-3-3 protein, a member of a large family of regulatory and binding proteins that is a proposed marker for Creutzfeldt-Jakob disease (but distinct from the prion protein). A better test than the assay for 14-3-3 protein needs to be developed, since levels of this protein are frequently normal in persons with new variant Creutzfeldt-Jakob disease and may be increased in both sporadic cases of Creutzfeldt-Jakob disease and nonprion diseases. (9)

Although no patient with new variant Creutzfeldt-Jakob disease has been identified among those thought to have a prion disease, ascertainment of cases has been incomplete. Autopsies are performed infrequently in patients with prion diseases, at least in part because of concern about safety on the part of pathologists. To improve surveillance, physicians should be aware of current monitoring efforts. Autopsies should be performed in all cases of prion disease in order to identify "florid plaques" (1) and on that basis diagnose new variant Creutzfeldt-Jakob disease definitively. This effort should be facilitated by the subsidy of the associated costs and the establishment of regional pathology centers to assist with or conduct autopsies.

The safety of the blood supply has received special attention, since studies suggest that prions are present in blood and bone marrow in BSE and in lymphoid tissues in new variant Creutzfeldt-Jakob disease. (10) If blood products such as intravenous immune globulin were contaminated, they could lead to widespread infection, since they are prepared from huge pools of donors and are administered to many recipients. On the other hand, the absence of cases of new variant Creutzfeldt-Jakob disease among patients with hemophilia is reassuring. (11) At present, potential blood donors in the United States who have clinical features resembling those of new variant Creutzfeldt-Jakob disease are excluded from the pool of donors, and any blood or blood product from a donor in whom new variant Creutzfeldt-Jakob disease subsequently develops is destroyed.

In order to address the risk of blood donation from normal persons who have been exposed to BSE but also to avoid life-threatening blood shortages, potential donors who have lived in the United Kingdom for six or more cumulative months between 1980 and 1996 are excluded. Extending this policy to people who have lived in other European countries is prudent, given the increase in the numbers of cases of BSE. Such exclusions should also be considered for donors of other tissues, especially dura mater and corneas collected after death. These tissues are easily contaminated with central nervous system tissue, which could cause iatrogenic Creutzfeldt-Jakob disease if the donor had unrecognized disease. (12)

The long incubation period for prion diseases still makes it uncertain how extensive the outbreak of new variant Creutzfeldt-Jakob disease will be. It is clear, however, that we need strong safeguards. Federal regulatory agencies must intensify programs of surveillance and control. These efforts will require additional funding, and a high priority should be given to the development of diagnostic tests for case surveillance and screening of donors. In addition, an advisory committee on prion disease needs to be established as an independent umbrella group, with representatives from the federal regulatory agencies, academia, industry, and the public. Such a committee could address issues that overlap or fall between the jurisdictions of the individual agencies and provide overall guidance.

Raymond P. Roos, M.D. , University of Chicago,Pritzker School of Medicine, Chicago, IL 60637


18 May 01 - CJD - Politicians blamed as BSE spreads in France

By Harry de Quetteville in Paris

Telegraph--Friday 18 May 2001


A damning report on the spread of Mad Cow disease in France has accused successive governments of deliberately blocking safety measures to prevent its transmission to other cows and to humans.

The report, released yesterday after a six-month inquiry by French senators, also described dangerous mismanagement and political infighting at France's Ministry of Agriculture. It says that in the nineties government ministers and officials chose to ignore mounting evidence of the dangers posed to humans by Bovine Spongiform Encephalopathy (BSE).

The report said: "The Ministry of Agriculture constantly sought to obstruct or delay precautionary measures that have since been shown to be key matters of health and safety." At the French National Assembly the chairman of a separate BSE inquiry, which is due to publish its own report next month, was equally damning.

MP François Sauvadet told Le Figaro: "From testimony we have established that politicians at the highest level have played with public health in the name of economic interests." The senatorial report's highly critical assessment of French government action from July 1988 to 2001 could plunge France into a new health scandal only two years after three leading politicians were in the dock over official distribution of Aids-tainted blood.

M Sauvadet said: "Its time that an account is made before public opinion and, if necessary, before the courts. The contaminated blood scandal has shown us the way and we know we can see it through to the end." So far there have been three deaths in France from new variant Creutzfeldt-Jakob (nvCJD), the braIndependentwasting disease, but according to the report France must expect several hundred more.

It concluded that Ministry of Agriculture allegations that the spread of BSE in France was due to illegal imports of potentially infected feed from Britain were unfounded. Instead, the report says, the spread of BSE in France was down to domestic delays in banning dangerous fodder and to the contamination of cattle feed with feed containing bone meal intended for other animals.

France has reported 317 cases of BSE since 1991, but reported numbers have increased steadily with wider testing in recent years. Last year 162 cases were discovered, while 75 have already emerged this year.


18 May 01 - CJD - French bse study condemns British animal feed trade

By John Lichfield in Paris

Independent--Friday 18 May 2001


An official French report on the spread of BSE yesterday attacked the "unjustifiable attitude" of the British government of 1988-90, which allowed potentially contaminated animal feed to be exported legally to the Continent.

But the report, by a committee of inquiry of the French Senate, also rounds on successive French agriculture ministers and the European Commission for putting agricultural economics ahead of human health.

The 362-page report said that four French agriculture ministers, between 1993 and 2000, including Jean Glavany, the current minister, failed to take adequate measures to protect animal and human health from BSE.

The French agriculture ministry had delayed the adoption of controls on feedstuffs and the human consumption of cattle offal, said the report.

The report also undermines the arguments made by the French government when it defied EU orders in 1999 and banned limited imports of "young" British beef which had been declared safe by Brussels.

Paris said, at that time, that it was pursuing a policy of zero tolerance of risks to human health. The report says that, in fact, the French government had consistently ignored warnings that its own protective measures against BSE, and its human variant, CJD, were not effective enough.

The committee says that the "principal cause" of the spread of BSE to France was the import of contaminated British animal feed in the late 1980s. The report points out that the then Thatcher government in Britain banned the use of ground-up cattle remains in cattle feed in July 1988.

It decided, however, to allow the feed to be sold to the Continent, even though it knew that the likely result would be the export of the disease. This was an "unjustifiable attitude", the French report said.

The French government did not ban imports of British bone meal for use in cattle feed for another year.


17 May 01 - CJD - PNAS - prion disease incubation period in mice

Collinge et al

Proc. Nat. Acad. Sci.--Thursday 17 May 2001


Genetics Identification of multiple quantitative trait loci linked to prion disease incubation period in mice

Sarah E. Lloyd, Obia N. Onwuazor, Jonathan A. Beck, Gary Mallinson, Martin Farrall§, Paul Targonski§, John Collinge,,¶, and Elizabeth M. C. Fisher

Medical Research Council Prion Unit and Department of Neurogenetics, Imperial College School of Medicine at St Mary's, Norfolk Place, London W2 1PG, United Kingdom; and § Department of Cardiovascular Medicine, University of Oxford, The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, United Kingdom

Communicated by Charles Weissmann, Imperial College of Science, Technology, and Medicine, London, United Kingdom, March 14, 2001 (received for review January 15, 2001)

Abstract

Polymorphisms in the prion protein gene are known to affect prion disease incubation times and susceptibility in humans and mice. However, studies with inbred lines of mice show that large differences in incubation times occur even with the same amino acid sequence of the prion protein, suggesting that other genes may contribute to the observed variation. To identify these loci we analyzed 1,009 animals from an F2 intercross between two strains of mice, CAST/Ei and NZW/OlaHSd, with significantly different incubation periods when challenged with RML scrapie prions. Interval mapping identified three highly significantly linked regions on chromosomes 2, 11, and 12; composite interval mapping suggests that each of these regions includes multiple linked quantitative trait loci. Suggestive evidence for linkage was obtained on chromosomes 6 and 7. The sequence conservation between the mouse and human genome suggests that identification of mouse prion susceptibility alleles may have direct relevance to understanding human susceptibility to Bovine Spongiform Encephalopathy (BSE) infection, as well as identifying key factors in the molecular pathways of prion pathogenesis. However, the demonstration of other major genetic effects on incubation period suggests the need for extreme caution in interpreting estimates of variant Creutzfeldt-Jakob disease epidemic size utilizing existing epidemiological models.

Introduction

The appearance of the novel human prion disease variant Creutzfeldt-Jakob disease (vCJD) and the confirmation that it is caused by the Bovine Spongiform Encephalopathy (BSE) prion strain, has led to concerns that a major epidemic of vCJD will evolve over the years ahead (1-3).

Prion diseases have prolonged incubation periods and coding polymorphisms in the prion protein (PrP) gene are known to affect incubation times and susceptibility in humans, mice, and sheep (4-8). In the human PrP gene (PRNP), a polymorphism occurs at codon 129 where either a methionine or valine may be encoded. Acquired and sporadic prion diseases occur mostly in homozygous individuals, and a protective effect of heterozygosity is also seen in some inherited cases (4, 5, 9). All cases of vCJD described to date have occurred in methionine homozygous individuals, a genotype shared by 40% of the British Caucasian population (10). In mice, two polymorphisms in the murine PrP gene (Prnp) have been described where Prnpa (Leu-108, Thr-189) and Prnpb (Phe-108, Val-189) are associated with short and long incubation times, respectively (6, 11-13).

Although the influence of PrP gene polymorphisms on susceptibility and incubation time is well established, other lines of evidence indicate that PrP amino acid differences are not the sole genetic influence (14-16). Comparison of several inbred lines of laboratory mice with the same Prnp genotype reveals major differences in incubation times to a defined prion strain (varying from 100 to 500 days), suggesting that other factors including additional genetic loci may contribute to the observed variation (11, 12, 17, 18). The identification of these loci in humans may allow identification of at risk individuals, allow more robust predictions of human epidemic parameters, and identify prion ligands and biochemical pathways that will allow a better understanding of prion pathogenesis and the development of rational therapeutics.

Direct identification of human quantitative trait loci (QTL) is both technically challenging and expensive because of the large sample sizes that are necessary to detect alleles of modest effect in randomly mating populations. The advantages of studying organisms in which breeding designs are under experimental control are well recognized; the availability of inbred lines of mice, the ability to generate large genetic crosses, and the similarity of the mouse and human genomes make mice an excellent model for identifying susceptibility loci.

Materials and Methods

Mice. NZW/OlaHsd were obtained from Harlan U.K. Ltd. (Bicester, U.K.) and CAST/Ei mice were obtained from the Medical Research Council Mammalian Genome Center (Harwell, U.K.). The F1 generation was generated in two ways: male CAST/Ei ? female NZW/OlaHsd and female CAST/Ei ? male NZW/OlaHsd. The F2 generation was established by intercrossing the F1s in all four possible combinations (Table 2). A subcutaneous transponder tag identified mice individually.

Inoculation and Phenotyping. Chandler/RML mouse adapted scrapie was obtained from A. Aguzzi (Institute of Neuropathology, University of Zurich, Zurich) and passaged once in CD1 Swiss mice (Harlan U.K. Ltd.). The presence of the Prnpa allele was confirmed in CD1 Swiss mice by sequencing. Brains from these animals were used to generate a 1% homogenate in PBS, which was used as the inoculum for all subsequent experiments. Mice were anaesthetized with halothane/O2 and inoculated intracerebrally into the right parietal lobe with 30 µl of the inoculum. All mice were examined daily for the development of clinical signs of scrapie. At onset of signs, mice were examined more rigorously for neurological signs of disease. Animals were culled as soon as clinical scrapie was confirmed or if showing signs of distress. Criteria for clinical diagnosis of scrapie in mice were as described (6). Incubation time was measured by the number of days from inoculation to the onset of clinical scrapie.

Genotyping. DNA was extracted from 1-cm tail biopsies by using a Promega DNA extraction kit and resuspended in 100 µl of TE (10 mM Tris·HCl/1 mM EDTA, pH 7.5). This stock DNA (0.5 µl of a 1:10 dilution) was used as template in a 5-µl PCR. All PCRs were carried out in 96-well plates either by using an 877 Integrated Thermal Cycler (Applied Biosystems) or a PTC-225 (MJ Research, Cambridge, MA). Fluorescently labeled primers were selected from the mouse MapPairs set (Research Genetics, Huntsville, AL), and additional primers were obtained from Sigma-Genosys. PCR conditions were determined empirically for each primer pair, but in general reactions were carried out in 3 mM MgCl2 with AmpliTaq-Gold (Applied Biosystems) in the buffer provided. Cycling conditions were as follows: 94°C for 10 min; 94°C for 30 s, 55°C for 30 s, 72°C for 30 s for 35 cycles; 72°C for 5 min. Alleles were detected on a 377 sequencer (Applied Biosystems) and analyzed by using GENOTYPER software (Applied Biosystems).

Data Analysis. Statistical analyses were carried out by using STATVIEW (SAS Institute, Cary, NC). Incubation times were log transformed for interval linkage analysis by using MAPMAKER/EXP 3.0 and MAPMAKER-QTL programs (19) to calculate logarithm of odds (lod) scores for free, dominant, recessive, and additive QTL models. Composite interval mapping (20, 21), which combines interval mapping with multiple regression, was performed with the QTL CARTOGRAPHER computer package (22, 23) in an analysis of the markers on chromosomes 2, 11, and 12. In the first stage of the analysis, the SRMAPQTL program, which uses the technique of forward stepwise regression, was used to construct a multilocus model. Markers were added to the model if they improved the overall fit at the P< 0.1 significance level. At the end of this procedure, all included markers were retested (by backward elimination) to check that they were still significantly retained in the multilocus model. The ZMAPQTL program was used to perform composite interval mapping, which allows for the presence of more than one QTL per chromosome under the assumption that the constitutive QTL do not interact epistatically. In composite interval mapping, the vector of trait values (Y) is fitted in a multiple regression model:

where b* and d* are additive and dominance effects for a putative QTL, x* and z* are indicator variable vectors of genotype probabilities calculated by interval mapping techniques, B is a vector of effects and X is the marker information matrix for the selected background markers, and E is the random error vector. Maximum likelihood estimates of the parameters are calculated by using an ECM (Expectation/Conditional Maximization) algorithm (24). Under the null hypothesis, H0: Y = XB + E, the residual variance will be s. Under the alternative hypothesis, H1: Y = x*b* + z*d* + XB + E, the residual variance would be s. The proportion of variance explained by a QTL at a test location conditioned on the background markers can be defined as r2 = (s s)/s2, where s2 is the trait variance. Alternatively, the proportion of the total variance explained by the QTL and the background markers (r) is defined as

Results and Discussion

In mice, prion disease incubation time can be treated as a continuous or quantitative trait that ranges from around 100 to over 500 days and is known to be influenced by many factors, including route of infection, dose, prion strain, levels of PrP expression, and genetic susceptibility (25). To identify QTL for prion disease incubation time we generated an F2 intercross between two strains of mice, CAST/Ei and NZW/OlaHsd, with significantly different incubation times (Table 1) when inoculated intracerebrally with Chandler/RML scrapie prions. Sequencing the ORF of Prnp from the mouse colonies used in the cross confirmed that both parental strains were Prnpa/a and had no other coding differences. Incubation times were recorded for a total of 1,009 F2 animals. As detailed in Table 2, the F2 intercross was set up in four ways to test for the presence of epigenetic effects. Male and female F2 progeny (crosses 3 and 4) from cross-B fathers (male NZW/OlaHsd ? female CAST/Ei) have a significantly longer incubation time (P = 0.01) than animals (crosses 1 and 2) derived from cross-A fathers (male CAST/Ei ? female NZW/OlaHsd) as determined by two-way ANOVA. This effect is independent of maternal origin and genetic locus, therefore all linkage data shown represent a combination of all crosses (Table 3). Animals that died at inoculation, from intercurrent illness, or without showing clinical signs of scrapie were excluded from the analysis. However, this did not alter the expected genotype ratios for each locus examined. The mean incubation time (in days) for the F2 animals was 158 ± 26 with a minimum of 99 and maximum of 274. The upper limit of this range (274 days) is substantially greater than the CAST/Ei parental incubation time (188 ± 12), suggesting a greater number of "long" incubation time QTL in these animals as a result of independent assortment of "long" and "short" alleles from both the NZW/OlaHsd and CAST/Ei parents. The distribution of the F2 log transformed incubation times had a skewness of 0.86 and a kurtosis of 0.99.

View this table: [in this window] [in a new window]

Table 1. Incubation times

View this table: [in this window] [in a new window]

Table 2. Experimental crosses

View this table: [in this window] [in a new window]

Table 3. Results of genome scan in F2 intercross (MAPMAKER analysis)

The genome screen was carried out in two stages. In the first stage, 400 F2 animals were genotyped with 137 fluorescently labeled primers (Research Genetics, Huntsville, AL) covering the whole genome with an average intermarker distance of 11 cM. The largest intermarker interval was 27.3 cM. Linkage analysis was carried out on this data set by using the MAPMAKER/EXP 3.0 and MAPMAKER-QTL programs (19). Regions that gave lod scores of greater than 2 were followed up in stage 2 with a more extensive screen. In this stage, a further 600 F2 animals were genotyped with markers selected from the first screen. In addition, all 1,009 mice were genotyped with an additional 20 markers selected from the Mouse Genome Database to increase the mapping resolution in regions of interest. Incubation times were log transformed (to ensure homoscedascity) for interval linkage analysis with MAPMAKER-QTL, where the QTL models were not constrained. The thresholds for significant (genome-screen P-value<0.05) and suggestive linkage were taken as lod scores of 4.3 and 2.8, respectively (26). Chromosomes 2, 11, and 12 show regions of highly significant linkage (Table 3 and Fig. 1), whereas suggestive linkage is seen on chromosomes 6 and 7 (Table 3).

View larger version (13K): [in this window] [in a new window]

Fig. 1. Lod score plots obtained for 1,009 F2 animals on (a) chromosome 2, (b) chromosome 11, and (c) chromosome 12. All plots represent output from MAPMAKER-QTL showing the results from the unconstrained genetic model. The vertical axis shows the lod scores and the horizontal axis displays the relative positions of the markers along the chromosome from centromere (Left) to telomere (Right) in cM as determined by MAPMAKER. The dashed horizontal line shows the lod score (4.3), which represents significant linkage (26).

The data for chromosomes 2, 11, and 12 was analyzed further in a composite interval mapping analysis by using the computer package QTL CARTOGRAPHER. This approach tests for a putative QTL in an interval while using other (linked or unlinked) markers as covariates in a multivariate model to reduce the residual variance with the result that the efficiency of the linkage test can be improved. Forward stepwise regression analysis (SRMAPQTL) identified seven markers contributing significantly to overall model goodness of fit (Table 4). Composite interval mapping results (ZMAPQTL), controlling for the seven markers identified in the previous step and examining the complete maps for chromosomes 2, 11, and 12, are presented in Table 5. Multiple linked QTL were identified on all three chromosomes; the three chromosomes jointly explained 82% of the total variance of log-incubation time (r, Table 5).

View this table: [in this window] [in a new window]

Table 4. Markers identified in stepwise regression

View this table: [in this window] [in a new window]

Table 5. Composite interval mapping results

The composite interval analysis (20, 21) suggests that multiple linked QTL underlie the linked regions identified in the interval mapping (MAPMAKER) analysis, which searches for a single QTL at a time. Maximum lod scores were observed in several intervals of markers not identified in stepwise regression; however, the stepwise regression analysis was intended only to identify potential background contributions. Modest significant effects were observed for three linked QTL on chromosomes 2 and 12, but two linked QTL on chromosome 11 were found to account for over 45% of the total variance observed for this trait. This analysis did not explore potential epistasis or gene-environment interactions, which may have contributed to the overall r2 for individual QTL. These results will be useful to guide the design and interpretation of advanced crosses and/or congenic lines that we plan to construct to fine-map and positionally clone the loci that underlie the three linked regions.

Prnp and its paralogue Prnd both map within the 95% confidence interval for the peak lod score of 8.2 on chromosome 2 (Fig. 1a), thus providing excellent candidates for the QTLalthough there are no amino acid differences between CAST/Ei and NZW/OlaHsd for either PrP or Dpl (data not shown), suggesting that regulatory regions may be important (27). Restriction fragment length polymorphisms around the Prnp locus have been described (12) where CAST/Ei is haplotype Prnpe and NZW/OlaHsd is Prnpa, suggesting that differences exist between the two strains in this region. This is not particularly surprising because CAST/Ei and NZW/OlaHsd are only distantly related (28). Polymorphisms have been identified in the promoter of Prnp, which have been implicated in regulating levels of expression (29, 30). We have identified single nucleotide polymorphisms in the promoter of Prnp between CAST/Ei and NZW/OlaHsd, but their significance remains to be determined (data not shown). Expression levels of PrP are known to correlate inversely with incubation time in knockout and transgenic mice (31, 32). PrPc levels were measured in the brains of 8-week-old CAST/Ei and NZW/OlaHsd parents, but in preliminary experiments no substantial differences were detected (data not shown). The genotype means for D2Mit107 are 165 and 152 days for NZW/OlaHsd and CAST/Ei homozygotes, respectively, which is the reverse of what would be expected based on the parental incubation times and that observed with all other linked loci (Tables 1 and 3). This is consistent with the observation that some F2 animals have an incubation time greater than either of the parental strains and reflects the fact that both NZW/OlaHsd and CAST/Ei have both "long" and "short" incubation time alleles, which segregate independently in the F2 generation. The genotype means for D2Mit107 (Table 3) also show significant differences for all genotypes (P< 0.005), suggesting an additive pattern of inheritance.

Of the total variance observed in this cross, 45% maps to two loci on chromosome 11. Numerous potential candidate genes map to this region of chromosome 11; however, further work will be required to refine the mapping data.The genotype means for markers on chromosome 11 (Table 3) show significant differences for all genotypes (P< 0.0001), suggesting an additive model of inheritance for these QTL.

The genotype means on chromosomes 12 show evidence of dominant inheritance with significant difference (P< 0.0001) observed between the N/N and C/C and also N/N and N/C genotypes, but not between C/C and N/C. The region of linkage spans over 20 cM, which includes many potential candidate genes such as Prpl3 (prion protein ligand 3) (33). Prpl3 was identified by its ability to bind PrPc and was mapped to chromosome 12 by restriction fragment length polymorphism analysis in a Jackson Laboratory interspecific backcross (33). Prpl3 shows 81% sequence identity to the human EST H06169, which on a BLAST search against the GenBank htgs database gives a 97% sequence identity match to a sequence derived from bacterial artificial chromosome (BAC) RP11-422L23 (GenBank accession no. AL356322), which has been mapped to the human X chromosome. This region of mouse chromosome 12 is reported to have homology to human chromosome 14; therefore, to clarify the location of Prpl3, primers were designed to the mouse cDNA sequence and used to screen the T31 radiation hybrid panel. Our data place Prpl3 13.93 cR from DXMit38, confirming its location on mouse chromosome X and excluding it as a candidate QTL for prion disease incubation time. However, it remains a possibility that the X chromosome locus represents a pseudogene and that the real gene is on mouse chromosome 12 and human chromosome 14.

A preliminary survey for genetic interaction between the linked loci was conducted by using two-way ANOVA. Only marginal significance was detected between D11Mit179 and D12Mit28 (P = 0.016), suggesting that the three regions generally act independently (additively) to influence the incubation time phenotype.

We have demonstrated unequivocally that genetic loci other than the ORF of Prnp can have a major effect on prion disease incubation time in mice and, furthermore, have identified eight QTL on three chromosomes that explain 82% of the variance. Although refining the regions of linkage identified in this study and characterizing relevant polymorphisms will still require considerable work, this study provides hope that we may also be able to identify human alleles that predispose to a shorter incubation time for BSE in humans.

Previous reports suggested a QTL for incubation time on chromosome 17 within the H2 locus of the major histocompatibility complex, although this was not replicated by others or identified in our cross (18, 34). However, challenge with different prion strains by different routes of inoculation and in other strains of mice may result in the segregation of alternative susceptibility genes. Recently, a much smaller study, which looked at only 153 F2 animals from an SJL/J and CAST/Ei intercross, identified loci on chromosomes 9 and 11 (35). The chromosome 9 locus was not identified in our cross, suggesting that this may be an SJL/J-specific effect. The chromosome 11 locus falls within the broad region of linkage described here, which is consistent with the suggestion that mouse chromosome 11 contains multiple QTL.

The identification of QTL for prion disease incubation time cast doubt on the validity of the genetic models used in current epidemiological studies, which may result in overly optimistic predictions of the size of the vCJD epidemic (36). These models assume that only methionine homozygous individuals are susceptible to vCJD. This in itself appears unlikely because the other acquired human prion diseases, iatrogenic CJD and kuru, occur in all codon 129 genotypes as the epidemic evolves, with codon 129 heterozygotes having the longest mean incubation periods (37-39). By definition, the patients identified to date with vCJD are those with the shortest incubation periods for BSE. These in turn, given that no unusual history of dietary, occupational, or other exposure to BSE has been identified, would be expected to be predominantly those individuals with short incubation time alleles at these multiple genetic loci in addition to having the codon 129 methionine homozygous PRNP genotype (38). The vCJD cases reported to date may, therefore, represent a distinct genetic subpopulation with unusually short incubation periods to BSE prions. Collectively, the effect on susceptibility and incubation time of the loci mapped could be more significant than that exerted by the PRNP locus itself. It should also be considered that variation of prion incubation periods between inbred mouse lines is even greater when considering transmission from one mammalian species to another (for instance with BSE transmission to mice). Here, additional genes involved in the species barrier itself would also be relevant. Because the frequencies of such genetic polymorphisms, alone or in combination, are unknown, this severely limits the utility of epidemiological predictions based only on these early vCJD patients.

Acknowledgements

We thank R. J. Bond and D. Moore for technical assistance. This work was funded by the United Kingdom Medical Research Council. P.T. was supported through the Mayo Foundation Scholarship scheme.

Abbreviations

BSE, Bovine Spongiform Encephalopathy; CJD, Creutzfeldt-Jakob disease; vCJD, variant CJD; QTL, quantitative trait loci; lod, logarithm of odds; PrP, prion protein; Dpl, doppel protein.

Footnotes

¶ To whom reprint requests should be addressed. E-mail: j.collinge@ic.ac.uk.

References

1. Collinge, J. , Sidle, K. C. L. , Meads, J. , Ironside, J. & Hill, A. F. (1996) Nature (London) 383, 685-690[Medline].

2. Hill, A. F. , Desbruslais, M. , Joiner, S. , Sidle, K. C. L. , Gowland, I. & Collinge, J. (1997) Nature (London) 389, 448-450[Medline].

3. Bruce, M. E. , Will, R. G. , Ironside, J. W. , McConnell, I. , Drummond, D. , Suttie, A. , McCardle, L. , Chree, A. , Hope, J. , Birkett, C. , et al. (1997) Nature (London) 389, 498-501[Medline].

4. Collinge, J. , Palmer, M. S. & Dryden, A. J. (1991) Lancet 337, 1441-1442[Medline].

5. Palmer, M. S. , Dryden, A. J. , Hughes, J. T. & Collinge, J. (1991) Nature (London) 352, 340-342[Medline].

6. Carlson, G. A. , Kingsbury, D. T. , Goodman, P. A. , Coleman, S. , Marshall, S. T. , DeArmond, S. J. , Westaway, D. & Prusiner, S. B. (1986) Cell 46, 503-511[Medline].

7. Hunter, N. , Goldmann, W. , Smith, G. & Hope, J. (1994) Arch. Virol. 137, 171-177[Medline].

8. Westaway, D. , Zuliani, V. , Cooper, C. M. , Da Costa, M. , Neuman, S. , Jenny, A. L. , Detwiler, L. & Prusiner, S. B. (1994) Genes Dev. 8, 959-969[Abstract].

9. Baker, H. E. , Poulter, M. , Crow, T. J. , Frith, C. D. , Lofthouse, R. , Ridley, R. M. & Collinge, J. (1991) Lancet 337, 1286-1286[Medline].

10. Collinge, J. , Beck, J. , Campbell, T. , Estibeiro, K. & Will, R. G. (1996) Lancet 348, 56-56[Medline].

11. Westaway, D. , Goodman, P. A. , Mirenda, C. A. , McKinley, M. P. , Carlson, G. A. & Prusiner, S. B. (1987) Cell 51, 651-662[Medline].

12. Carlson, G. A. , Goodman, P. A. , Lovett, M. , Taylor, B. A. , Marshall, S. T. , Peterson-Torchia, M. , Westaway, D. & Prusiner, S. B. (1988) Mol. Cell. Biol. 8, 5528-5540[Medline].

13. Moore, R. C. , Hope, J. , McBride, P. A. , McConnell, I. , Selfridge, J. , Melton, D. W. & Manson, J. C. (1998) Nat. Genet. 18, 118-125[Medline].

14. Hill, A. F. , Butterworth, R. J. , Joiner, S. , Jackson, G. , Rossor, M. N. , Thomas, D. J. , Frosh, A. , Tolley, N. , Bell, J. E. , Spencer, M. , et al. (1999) Lancet 353, 183-189[Medline].

15. Owen, F. , Poulter, M. , Collinge, J. & Crow, T. J. (1990) Am. J. Hum. Genet. 46, 1215-1216[Medline].

16. Will, R. G. , Zeidler, M. , Stewart, G. E. , Macleod, M. A. , Ironside, J. W. , Cousens, S. N. , Mackenzie, J. , Estibeiro, K. , Green, A. J. E. & Knight, R. S. (2000) Ann. Neurol. 47, 575-582[Medline].

17. Dickinson, A. G. (1975) Genetics 79,Suppl, 387-395.

18. Kingsbury, D. T. , Kasper, K. C. , Stites, D. P. , Watson, J. D. , Hogan, R. N. & Prusiner, S. B. (1983) J. Immunol. 131, 491-496[Abstract].

19. Lander, E. S. , Green, P. , Abrahamson, J. , Barlow, A. , Daly, M. J. , Lincoln, S. E. & Newburg, L. (1987) Genomics 1, 174-181[Medline].

20. Zeng, Z. (1993) Proc. Natl. Acad. Sci. USA 90, 10972-10976[Abstract].

21. Zeng, Z. (1994) Genetics 136, 1457-1468[Abstract].

22. Smith, C. , Gavora, J. S. , Benkel, B. , Chesnais, J. , Fairfull, W. , Gibson, J. P. , Kennedy, B. W. & Burnside, E. B. (1994) Proc. 5th World Congr. Genet. Appl. Livestock Prod. 22, 65-66.

23. Basten, C. J., Weir, B. S. & Zeng, Z.-B. (2000) QTL Cartographer 1.14.

24. Meng, X. & Rubin, D. B. (2001) Biometrika 80, 267-268.

25. Hunter, N. , Dann, J. C. , Bennett, A. D. , Somerville, R. A. , McConnell, I. & Hope, J. (1992) J. Gen. Virol. 73, 2751-2755[Abstract].

26. Lander, E. & Kruglyak, L. (1995) Nat. Genet. 11, 241-247[Medline].

27. Moore, R. C. , Lee, I. Y. , Silverman, G. L. , Harrison, P. M. , Strome, R. , Heinrich, C. , Karunaratne, A. , Pasternak, S. H. , Chishti, M. A. , Liang, Y. , et al. (1999) J. Mol. Biol. 292, 797-817[Medline].

28. Beck, J. A. , Lloyd, S. , Hafezparast, M. , Lennon-Pierce, M. , Eppig, J. T. , Festing, M. F. & Fisher, E. M. (2000) Nat. Genet. 24, 23-25[Medline].

29. Westaway, D. , Cooper, C. , Turner, S. , Da Costa, M. , Carlson, G. A. & Prusiner, S. B. (1994) Proc. Natl. Acad. Sci. USA 91, 6418-6422[Abstract].

30. Baybutt, H. & Manson, J. (1997) Gene 184, 125-131[Medline].

31. Prusiner, S. B. , Scott, M. , Foster, D. , Pan, K. M. , Groth, D. , Mirenda, C. , Torchia, M. , Yang, S. L. , Serban, D. , Carlson, G. A. , et al. (1990) Cell 63, 673-686[Medline].

32. Bueler, H. , Raeber, A. , Sailer, A. , Fischer, M. , Aguzzi, A. & Weissmann, C. (1994) Mol. Med. 1, 19-30[Medline].

33. Yehiely, F. , Bamborough, P. , Da Costa, M. , Perry, B. J. , Thinakaran, G. , Cohen, F. E. , Carlson, G. A. & Prusiner, S. B. (1997) Neurobiology 3, 339-355.

34. Mohri, S. & Tateishi, J. (1989) J. Gen. Virol. 70, 1391-1400[Abstract].

35. Stephenson, D. A. , Chiotti, K. , Ebeling, C. , Groth, D. , DeArmond, S. J. , Prusiner, S. B. & Carlson, G. A. (2000) Genomics 69, 47-53[Medline].

36. Ghani, A. C. , Ferguson, N. M. , Donnelly, C. A. & Anderson, R. M. (2000) Nature (London) 406, 583-584[Medline].

37. D'Aignaux, J. H. , Costagliola, D. , Maccario, J. , de Villemeur, T. B. , Brandel, J. P. , Deslys, J. P. , Hauw, J. J. , Chaussain, J. L. , Agid, Y. , Dormont, D. , et al. (1999) Neurology 53, 1197-1201[Abstract/Full Text].

38. Collinge, J. (1999) Lancet 354, 317-323[Medline].

39. Cervenáková, L. , Goldfarb, L. G. , Garruto, R. , Lee, H. S. , Gajdusek, D. C. & Brown, P. (1998) Proc. Natl. Acad. Sci. USA 95, 13239-13241[Abstract/Full Text].

">

17 May 01 - CJD - Leather becomes costly

By Torri Barco

Bend Bulletin--Thursday 17 May 2001


The price of U.S. cowhide is soaring and the cost of finished leather will soon follow, the first major repercussions here from Europe's twin plagues of foot-and-mouth and "mad-cow" disease.

American shoppers could end up paying as much as $1.5 billion more for leather goods over the next year, a Commerce Department economist said. The increases should be small on items such as purses and wallets, but products requiring more material, such as leather furniture and car seats, could rise by hundreds of dollars.

Leather retailers in Central Oregon are already seeing the rise.

David Hayes, the owner of Sullivan Glove Company in Bend, said six months ago he paid $1.40 per square foot for cowhide, but now pays $2.20 per square foot. Hayes said 5 percent of the store's gloves are made with cow leather.

"The prices have almost doubled," Hayes said. "But so far we haven't had any problems with supply.

" We're still able to get as much leather as we want."

Hayes said leather prices were already increasing before the awareness of cow diseases. He said he is confidant leather prices will continue to rise.

"I hope not," said John Maxwell, owner of U Sav Discount Leather in LaPine. "So far I haven't seen any major increase in leather, but mad-cow disease could effect it. My leather jackets are running on a tight margin. I have an 8 percent margin on the jackets, and that's not much. If the price goes up, I'll have no choice - I'll have to go up."

Laurie Turner, an employee of Spotted Mule Saddlery & Westernwear Inc., said her business has already seen a 6-to 8-percent increase in prices for finished leather products of saddlery and strapped leather since January.

"There is already a shortage of good supplies," Turner said. "It is hard to get quality hides for saddles. Even before the problems in Europe made the whole thing public, we were already projected a 12 percent increase in our leather goods."

Leather warehouses and tanneries are using the threat as a springboard for their business, said Gerald Hackett, owner of West Wind Saddlery Repair in Redmond.

"Our hide people are calling me and saying we better get our leather now before the supply goes down," Hackett said. "They're using it to increase their sales."

But Maxwell said he's a one-man shop and he buys the leather for his saddles on an as-needed basis.

He anticipates the cow diseases will add one more price factor for him to juggle.

"I know the prices will go up," Maxwell said. "I'm just not sure when...It's going to effect customers. For me to afford the materials, to run the shop with today's power prices, to pay to get from here to there, it's hard to keep the prices down."

Elsewhere in the U.S., "Businesspeople are taking this very seriously," said Jack Morgan, a spokesman for the American Apparel and Footwear Association."If the prices go up, there's a good likelihood the consumer will look for something else, either artificial or textile. Consumers have come to expect deals and specials and extremely competitive prices."

American hides are being bid up by desperate European manufacturers, which have run short on their own leather supply as millions of animals there are killed and burned.

The detection of foot-and-mouth disease in Argentina, another major exporter of hides, has squeezed the market further.

And if the shortage of healthy animals continues, price hikes are likely on a number of other nonleather items, because animal byproducts are used in the manufacture of lipstick, shampoo, cheese, candy and vitamins, among other products.

So far, the situation in Europe and elsewhere has not affected U.S. meat prices.

Few countries import American beef because of the use of growth hormones.

Small price increases on red meat, producers say, have come from this year's heavy rains across the country and are expected to subside in time for summer barbecues.

But that's little consolation to makers of leather goods.

U.S. tanners pay as much as 25 percent more for hides. Shoemakers have warned Wall Street about price hikes or a potential hit to corporate profits. And retailers are bemoaning yet another blow to already weak consumer spending.

"I've been in the business for 42 years, and I've never seen a supply shortage or anything even close to this," said Ken Purdy, president of Prime Tanning Co. of New Hampshire, one of the nation's largest leather suppliers.

"Somebody in the next six months' time has to absorb these price increases. When most manufacturers... price their new lines, any cost increase will be in there, you can bet on that."

In Britain alone, more than 2 million animals have been destroyed in efforts to stem transmission of foot-and-mouth disease. But that's only part of the reason for the shortage of animal hides.

Mad Cow, or Bovine Spongiform Encephalopathy, bears the brunt of the blame. Although the disease has not led to massive controlled kills, it has spawned a public relations nightmare for the European beef industry.

Unlike foot-and-mouth, which people do not easily contract, Mad Cow can be fatal in its human form, a variant of Creutzfeldt-Jakob disease.

Fear of the rare disease has for a decade whittled away at the demand for red meat in Europe, cutting beef consumption by half in that time.

And because the only economical way to harvest hides is by using special machines at the slaughterhouse, the reduction in beef consumption has served to reduce leather supplies.

The lack of demand also has sent European beef prices tumbling. In reaction, several European countries have ordered controlled cattle kills to try to boost prices.

That has led to the destruction of hundreds of thousands of healthy animals this year. Because those animals are not sent to the slaughterhouses, their hides are also unavailable.

The result, tanners say, is about 200,000 fewer hides available each week.

So far, American consumers mostly have been shielded from the price increases because retailers usually have fairly long contracts and are still paying pre-shortage prices. Bigger tanneries, meanwhile, are hoping to get by on older inventory until prices begin to recede.

Hides in storage, however, last only so long, Prime Tanning's Purdy said. By this fall, even the largest tanneries are likely to need more hides, he said, and few believe that the European crisis will have changed much by then.


17 May 01 - CJD - Ask the Pharmacist

Suzy Cohen

Marco Island Eagle---Thursday 17 May 2001


Dear Pharmacist,I take an energy formula that contains "animal sources" and I am wondering if it is possible that "Mad Cow Disease" could make it into our medicines and supplements? -BP, Gainesville

It is definitely possible. The products that are derived from animal parts like cow brain, spinal cord and adrenal glands are subject to contamination.

Many of these products are sitting out on the shelf at your local pharmacy or health food store. Their pretty labels suggest that you'll get more energy and a better memory. But products that contain "glandular" material could, theoretically, cause Creutzfeldt-Jackob disease in humans. That's the disease carried by "Mad Cows."

Since there are loose regulations on the quality of dietary supplements, be careful. If you are particularly concerned, avoid any supplement that contains beef or bovine "glandular" extracts. As for prescription medicine, don't worry yet, standards of purity are strict in the pharmaceutical industry.


17 May 01 - CJD - Study: Up to 300 French vCJD Cases in Next 60 Years

Reuters

YAHOO--Thursday 17 May 2001


PARIS (Reuters) - France can expect up to 300 cases of new variant Creutzfeldt-Jakob disease (vCJD), the human form of Mad Cow disease, in the next 60 years, a report published by the French Senate said on Thursday.

Three people are thought to have died already from the fatal braIndependentwasting disease in France, although the exact cause of death of the latest victim last month has not been confirmed.

The forecast from the French upper house is sharply lower than that offered by scientists for Britain, where more than 80 people have already died of the illness.

Epidemiological projections have put the maximum number of cases in Britain at up to 130,000.

But recent research by scientist John Collinge at the British Medical Research Council's Prion Research Unit has suggested there could be an epidemic evolving in waves over decades, Collinge said this week.

The French senators wrote in a report after an inquiry that scope for spread of the disease in France was limited.

``The most pessimistic theoretical forecast on contamination risks in France... shows the worst could be a risk of 300 cases (of vCJD) in the next 60 years, taking account of the incubation period,'' they wrote.

``This would mean the annual number of cases would be five, which shows the very limited development of the new variant,'' they added.

While the Senate report may offer comfort to a population worried about the impact of Mad Cow disease -- formally known as Bovine Spongiform Encephalopathy (BSE) -- it has already been challenged.

Annick Alperovitch, a researcher at the National Health and Medical Research Institute (INSERM) who testified at the Senate's inquiry, called its approach ``simplistic.''

She said it was based on the assumption of an average incubation period not exceeding 60 years and said it was possible some older people, believed to have succumbed to other illnesses, had actually been suffering from undetected vCJD.


17 May 01 - CJD - BSE: Risk assessments for Costa Rica, Kenya, Slovenia and Romania

European Commission

European Commission--Thursday 17 May 2001


-------------------------------------------------------------------------------- DN: IP/01/707 Date: 2001-05-16

TXT: FR EN DE PDF: FR EN DE Word Processed: FR EN DE

IP/01/707

Brussels, 16 May 2001

BSE: Scientists publish risk assessments for Costa Rica, Kenya, Slovenia and Romania

The Scientific Steering Committee (SSC) advising the European Commission on BSE related issues has today published its opinion on the Geographical Risk of Bovine Spongiform Encephalopathy (GBR) in Costa Rica, Kenya, Slovenia and Romania. The evaluation of the geographical risk of presence of BSE focuses on the risk for animals to incubate the disease. The Committee concludes that is highly unlikely that cattle infected with the BSE agent are present in domestic herds of Costa Rica (GBR level I). They found that this is unlikely but not excluded in the herds of Kenya and Slovenia (GBR level II) and that it is likely that BSE is present in the cattle herds of Romania (GBR level III) although this is not yet confirmed. Slovenia is the first accession country that is classified as GBR level II. All other accession countries evaluated so far have been classified at level III of Geographical BSE Risk. Similarly, all EU Member States are classified at level III except for Sweden, Finland and Austria (level II).

The Committee found that Slovenia has since 1992 imported 2.400 live cattle notably from Germany, and imported small amounts of MBM. The Slovenian authorities have been able to trace most of these cattle imports and to demonstrate that many of them are still alive. They also showed that reasonably effective controls on the rendering of MBM were in place at least as of 1996, and probably also before that date. In addition, a first feed ban to ruminants was introduced in 1996. It is therefore regarded unlikely but not excluded that the BSE agent could have been recycled, but not amplified, in Slovenia between 1992 and January 2001, when a complete feed ban was put in place. Romania has imported higher numbers of live cattle (about 22,000 tons) and meat-and-bone-meal (about 10,000 tons) from EU countries where the presence of BSE has since been confirmed. Although risk management measures were taken as of 1996, their effective enforcement has not been demonstrated. Therefore it is regarded likely that Romanian cattle herds were exposed to potentially BSE contaminated feed and subsequently infected.

Kenya has received meat and bone meal exports notably between 1987-1990 from the UK and since 1994 from Belgium, Denmark and the Netherlands. The data made available to the SSC do not exclude that some of this MBM has reached domestic cattle. The conclusion of the assessment for Costa Rica is based on data demonstrating that BSE infectivity is highly unlikely to have reached the country and hence the domestic cattle population. Only minor quantities of potentially infected live cattle (35 from Spain) or potentially contaminated meat-and-bone meal (5 tonnes) were imported into the country.

The SSC recommends that BSE related aspects are included in the programme of future inspection missions of the Food and Veterinary Office, as far as feasible, to obtain confirmation of the information received from the national authorities in the countries concerned. For the time being, the scientists underline, their assessment has to be based on the information provided by the assessed countries. As far as possible all data have been evaluated and verified in close co-operation with the countries concerned, and checked against other sources in an open and transparent manner. Data on imports provided by the countries under evaluation have for example been compared with export data as recorded by EUROSTAT, the EU Statistical Office, and with export data provided by the UK authorities.

The evaluation of the GBR in these third countries was made on the basis of the same method and assessment process as described by the SSC in its July 2000 opinion on the GBR((1)). In the July-opinion the scientists already assessed the GBR risk in all EU Member States except Greece, and a first series of third countries((2)). An assessment for Uruguay was published in January; assessments for Botswana, Lithuania, Namibia, Nicaragua, and Swaziland in February, and for Albania, Brazil, Colombia, Republic of Cyprus, Czech Republic, Estonia, Hungary, India, Mauritius, Pakistan, Poland, Singapore and Slovakia in April this year.

The full text of the opinions is available at:

http://europa.eu.int/comm/food/fs/sc/ssc/outcome_en.html

Updated Overview of third countries according to Geographical BSE risk classification

Category I: Highly unlikely to present a BSE risk

Argentina

Australia,

Botswana

Brazil

Chile

Costa Rica

Namibia

Nicaragua

Norway

New Zealand

Paraguay

Singapore

Swaziland

Uruguay

Category II: Unlikely, but a BSE risk cannot be excluded

Canada

Colombia

India

Kenya

Mauritius

Pakistan

Slovenia

USA

Category III: likely to present a BSE risk, even if not confirmed, or presenting a low level of confirmed BSE risk

Albania

Cyprus

Czech Republic

Estonia

Hungary

Lithuania

Poland

Romania

Slovak Republic

Switzerland

Category IV: BSE risk confirmed at a high level

None

(1) see IP of August1, 2000 at : HYPERLINK "http://europa.eu.int/comm/dgs/health_consumer/library/press/press66_en.html" http://europa.eu.int/comm/dgs/health_consumer/library/press/press66_en.html

(2) Argentina, Australia, Canada, Chile, Norway, New Zealand, Paraguay, Switzerland, USA


17 May 01 - CJD - Tests find deficiencies in measures designed to avoid Mad Cow disease

Associated Press

Associated Press---Thursday 17 May 2001


More than one third of Colorado cattle-feed producers failed at least part of a federal test of measures designed to keep Mad Cow disease out of the United States.

So far the disease has not reached American shores, but some industry observers say it is troubling that the protective measures aren't being observed at many points.

The Food and Drug Administration reported the test results in its national database.

The FDA is not yet issuing fines or sanctions to those who break the rules, calling its first rounds of inspections an educational exercise. Of 71 Colorado feed concerns inspected through late 2000 that handled cattle parts, 26 failed to add a warning label that would help prevent that feed from going to live cattle, or 37 percent of the total.

"The present system has no allowance for either human greed or human error, and that's a bad way to proceed," said Carol Tucker Foreman, director of the Food Policy Institute of the Washington, D.C.-based Consumer Federation of America. "It's such a devastating disease for both humans and animals; it's probably worthwhile to take all of the protective steps that we can."

The FDA issued rules in 1997 prohibiting the feeding of cattle or other ruminant parts to U.S. cattle.

More worrisome to some experts was the finding that at the 40 Colorado locations which handle both cattle remains and other protein from pigs or chickens, inspectors were not able to answer the vital question of whether those firms have a system to prevent co-mingling of the materials.

At least nine of those 40 firms also failed to apply the warning label, making it nearly impossible to tell what animal parts were in the feed.

And of 123 Colorado feed locations inspected overall, 35 said they were not aware of the regulations - although some of those were already following the safeguards as their normal practice.

The FDA, which conducted the inspections along with state regulators, is now trying to follow up at each site to see if its education effort brought better compliance with the Mad Cow rules. They are also instructing the state inspectors who helped them on how to properly complete the query forms.


17 May 01 - CJD - 1/3 of state's cattle-feed producers fail some inspections

Staff Reporter

Denver Post---Thursday 17 May 2001


While red-meat consumers may not be in danger because Mad Cow disease has not shown up in North America, some industry observers point to the failed inspections when calling for tougher rules and more testing for the disease.

"The present system has no allowance for either human greed or human error, and that's a bad way to proceed," said Carol Tucker Foreman, director of the Food Policy Institute of the Washington, D.C.-based Consumer Federation of America. "It's such a devastating disease for both humans and animals; it's probably worthwhile to take all of the protective steps that we can."

The U.S. Food and Drug Administration is not yet issuing fines or sanctions to those who break the rules, calling its first rounds of inspections an educational exercise. Of 71 Colorado feed concerns inspected through late 2000 that handled cattle parts, 26 failed to add a warning label that would help prevent that feed from going to live cattle, or 37 percent of the total.

British experts believe humans contracted a form of Mad Cow disease there by eating meat from cattle that were fed the rendered remains of diseased cattle.

The FDA issued rules in 1997 prohibiting the feeding of cattle or other ruminant parts to U.S. cattle.

More worrisome to some experts was the finding that at the 40 Colorado locations which handle both cattle remains and other protein from pigs or chickens, inspectors were not able to answer the vital question of whether those firms have a system to prevent co-mingling of the materials.

At least nine of those 40 firms also failed to apply the warning label, making it nearly impossible to tell what animal parts were in the feed.

And of 123 Colorado feed locations inspected overall, 35 said they were not aware of the regulations - although some of those were already following the safeguards as their normal practice.

The FDA, which conducted the inspections along with state regulators, is now trying to follow up at each site to see if its education effort brought better compliance with the Mad Cow rules. They are also instructing the state inspectors who helped them on how to properly complete the query forms.

"No excuse' for violations

While not enough Colorado firms have been reinspected to assess that goal, the FDA claims that of 157 feed-handling firms reviewed nationally, only one was still failing the rules test.

Feed and rendering industry officials said they may have resisted the rules at first because Mad Cow was never in the food chain here. But they worked with the FDA on the rules once it became clear the public and the government wanted more assurance, said Tom Cook, president of the National Renderers Association.

Cook has analyzed the inspection database and thinks Colorado companies responded well to the rules.

"We expect 100 percent compliance. There's no excuse for not complying," Cook said.

The best results from the inspections came in the rules for record-keeping, which require renderers, feed processors or mixers to maintain books allowing officials to track specific materials through their receipt, processing and distribution. As with other outbreaks of food-borne illnesses, this would allow regulators to find where diseased material entered the food chain and what feed needed to be recalled to solve the problem.

In Colorado, 136 inspections addressed the bookkeeping issue, and only seven firms failed the test, for a success rate of 95 percent.

The success and failure rates in Colorado for tests of various Mad Cow rules were similar to the national results reported by the FDA in more than 10,000 inspections.

Mad Cow disease is the common term for Bovine Spongiform Encephalopathy, a brain wasting malady that is always fatal and takes similar forms in other species, ranging from sheep to elk. In Britain, about 95 humans who ate meat tainted with Mad Cow disease are now suffering or have died from a human variant of the disease. Millions of cattle have been destroyed in Europe to try to eliminate any animals still carrying the disease.

British scientists believe their nation suffered a sudden outbreak because cattle there ate rendered protein tainted with diseased cattle or sheep parts.

Changes in Britain's rendering and feeding practices opened a brief window for the disease to spread in the food chain.

To counter the outbreak, other nations, including the United States, banned all imports of live cattle and processed meat from Britain. No cases of Mad Cow or its human variant have ever been diagnosed in the United States. But until the late 1990s, it was common in the U.S. cattle industry to use rendered cattle protein as a feed supplement to fatten herds.

FDA officials in 1997, further walling off the U.S. food chain, banned cattle operations here from feeding parts of cattle or other ruminants back to cattle.

Some want tougher ban

Some food experts want the livestock industry to go a few steps further and ban feeding any animal protein back to animals.

Some feedlots, for example, still use protein derived from poultry or pigs. Critics worry that since pigs and poultry can still consume cattle protein, and those pigs and poultry can then legally be fed back to cattle, the potential chain for Mad Cow's spread has not been broken.

The Consumer Federation's Foreman said a stiffer ban would keep the wrong kinds of feed from mixing due to either accident or dealers that ignore looser rules.

"These are commodities," she said.

"They are not tracked like medical devices" or diamonds, she added. "It goes out there by the ton. Controlling where it goes is really beyond their ability."

Wyoming, with far fewer feed sites to inspect than Colorado, reported mixed results.

Most of the 29 firms inspected were aware of the rules, but of the 15 that handled the prohibited ruminant materials, seven used no warning labels to keep that feed from going to cows.

All of the Wyoming firms reviewed were keeping the required records.


17 May 01 - CJD - Mother of CJD victim tells of fears for family

Staff Reporter

IC Teesside---Thursday 17 May 2001


The worried mother of a victim of the human form of BSE has told of her fears for the health of the rest of her family.

Peter Hall, of Chester-le-Street, County Durham, was one of the first victims of variant CJD when he died at the age of 20 five years ago.

His mother, Frances, is now secretary of the Human BSE Foundation.

And yesterday, after scientists revealed new evidence that an epidemic of the disease could be on the horizon, Mrs Hall told how her family keep a watch on each other, fearing the worst.

Mrs Hall said: "It's quite frightening.

"You tend to think if you have lost a member of your family five years ago that the danger period might be receding for you, but that doesn't necessarily follow.

"We are watching each other now. I have another son, so I worry very much that he ate what Peter ate.

"You try to push it to the back of your mind, but every time they discover something like this it's right there again.

"I just hope they concentrate on research into cures that can halt this disease, because the damage is already done."

Peter's parents received the post-mortem report the day before former Health Secretary Stephen Dorrell told the Commons that a new disease had been identified which was probably caused by infected beef.

Mrs Hall's other son, John, is now aged 30. She stopped buying beef for her family in 1989 when concerns were first raised about BSE, but it was too late for Peter. She said: "I will never, ever eat beef again."

The latest scientific investigation - led by Prof John Collinge at London's Imperial College - indicates the incubation period of variant CJD may depend on the genetic make-up of its victims.

In experiments with mice, Prof Collinge's team discovered the location of three new genes that help determine the incubation periods of diseases such as scrapie, BSE and variant CJD.

The scientists say it is almost certain that corresponding genes exist in humans, since mice and humans have many genetic similarities.

It is already known that people fall into three broad gene groups, labelled MM, VV and MV. It is a defective gene molecule that is thought to spread variant CJD.

All those who have so far developed the disease have been from the MM genotype.

Prof Collinge, whose findings are reported in the journal Proceedings of the National Academy of Sciences, said it was likely that within the MM group, there were differing degrees of susceptibility to diseases like variant CJD, and that the human counterparts of the genes located in mice would be crucial to this.

He said: "Those patients we have seen so far with variant CJD may be those genetically disposed to have the shortest incubation periods."

Experts have always known that the longer the disease took to incubate, the worse the final epidemic was likely to be.

One, consultant microbiologist Dr Stephen Dealler , said the new data supported his expectation that the number of cases would soon start to rise rapidly, peaking between 2010 and 2020.


17 May 01 - CJD - How safe is our meat?

John Patterson

Chicago Tribune--Thursday 17 May 2001


It's so American it could be draped in the flag, served on a Chevy tailgate and chased with mom's apple pie.

Oh, and there's the growing fear that it could sicken, if not kill you. First there was the nightmare of Mad Cow. Now foot-and-mouth disease appears to be running rampant across Europe and poses an economic threat should it emerge here.

Don't forget E. coli and salmonella: The two combine to sicken at least 113,000 people annually, according to the national Centers for Disease Control [Not to mention paratuberculosis bacteria which may be causing Crohn's disease--BSE coordinator].

At times it seems nothing is safe to eat, as if Charlton Heston is on the verge of yelling, "Soylent Green is people."

Relax and chew, say agriculture and food safety experts.

"We're probably as secure as anybody," said Jan Novakofski, an animal science professor at the University of Illinois who studies Mad Cow disease. A meat-eater himself, Novakofski said there are fewer than 100 known cases of Mad Cow disease in humans worldwide and none in the United States.

Given the number of people who eat meat - the average person in the United States is expected to consume 225.5 pounds this year, which includes everything from steak to chicken - the chances of getting sick or dying are pretty slim.

Those odds are due to government bans on imported meat, increased inspections and training, and probably a little luck, food safety experts say.

The U.S. Department of Agriculture banned the import of all cattle and most cattle products from the United Kingdom and other European countries in 1989 in response to Mad Cow outbreaks. The ban was expanded to include all of Europe in 1997.

All U.S. cattle must be inspected by the USDA before being slaughtered. Federal inspectors look for signs of neurological problems associated with Mad Cow disease. Animals showing possible symptoms are condemned, and the meat is not permitted for use as human food. The brains fro•these animals are sent to the USDA's National Veterinary Services Laboratories for analysis.

The ban on European cattle and meat imports for Mad Cow disease also has helped prevent the more recent foot-and-mouth disease outbreaks from coming here, experts say. Many of the latest efforts to prevent the disease from reaching the U.S. deal with travelers who have been to countries where foot-and-mouth is a problem.

For instance, the University of Illinois Department of Agriculture has restricted outside access to its facilities. And an outbreak of foot-and-mouth is such a threat that Illinois agriculture officials recently said they would immediately quarantine and destroy all animals at this summer's Illinois State Fair if an infected animal is found - a scenario that would include killing hundreds of prized livestock.

But the ban on imported meat and cattle doesn't mean every burger in the Chicago-area comes from a cow on a downstate farm. Illinois ranks 26th in the nation in the cattle industry. The meat we eat is more likely to come from cattle operations elsewhere in the Plains States. And as of 1999, the United States imported nearly 2.9 billion pounds of beef, mostly from Canada, Australia and New Zealand.

"In modern society, the concept of a local supply of food is very attractive mythology," Novakofski said. The demand of consumers makes that impossible, he said.

Knowing the enemy

Despite almost daily media attention about the diseases, Novakofski and other agriculture experts said most people don't know much about the illnesses, their causes, or health effects.

For instance, you can wash a steak with bleach and burn it to a crisp, but if it was infected with Mad Cow disease, it'll still be in there. That's because the disease is caused by a protein, not a virus or bacteria. This particular protein mutates, and in high enough concentrations, becomes toxic to nerve cells, Novakofski said. So far the disease has always been fatal, slowly eating away at the infected animal or person's brain and nervous system.

Preventing infection in the first place is the only way to stop its spread, Novakofski said. The spread of Mad Cow disease has been traced to leftover parts of dead cows carrying the mutant protein being ground up, added to cattle feed, and fed to other cows.

The process has been banned in the United States since 1997. Cattle from England cannot be imported here, and there has never been a confirmed case of Mad Cow disease in the United States. So, if the ban on feeding cow parts to cows is followed and enforced, there should be no problem.

But there have been problems, and that's where luck comes in. In Texas, U.S. Food and Drug Administration inspectors found cattle feed that contained meat and bone meal from other cattle. Earlier this year, the FDA announced that the feed contained very low levels of the prohibited material and said the risk of it being infected with Mad Cow disease was minimal. Nonetheless, the cows were not used for human consumption.

The Texas situation exemplifies how easily one slip up could change the face of agriculture in this country.

"We've never had (Mad Cow disease) in the United States, and we have the ban so hopefully it would never be transmitted. We know from England the feed ban works - as long as there's compliance," Novakofski said.

State Sen. Peter Roskam, a Wheaton Republican, has proposed legislation to step up the Illinois Department of Agriculture's inspection schedule. Currently, inspectors audit feed mills every two years. Roskam wants it changed to every 90 days.

He said Illinois should do "everything conceivable" to make sure Mad Cow never surfaces here. Roskam, an attorney, said he was motivated by his love of ribeyes.

Foot-and-mouth disease, on the other hand, seldom spreads from animals to humans, although a human form exists.

"One of the points people miss about foot and mouth, is that it is not a fatal disease (for animals or humans)," Novakofski said. "Typically it makes (animals) unproductive. They don't eat. They get lesions on the mouth. It takes a lot of care to get them back."

It is often more efficient to kill infected animals than heal them.

"The reason they kill all the animals is it's very contagious. It's almost like a forest fire," Novakofski said. "If it spreads, it's going to cause an economic disaster."

McDonald's executives blamed the European food problems for lower profits recently. The company's media relations department did not return calls.

And there may be fewer ribs at Taste of Chicago this summer because rib prices have skyrocketed since the European foot-and-mouth disease scare prompted the U.S. ban on hog imports. Baby back ribs are selling for $6 a pound compared with $2.60 last year.

While Mad Cow and foot-and-mouth capture headlines, other food illness like E. coli and salmonella remain a much more likely threat. Just last month a Canadian meat processor recalled 204,000 pounds of ground beef because of possible E. coli contamination. The beef was being distributed in the United States, including Illinois.

The national Centers for Disease Control reports there are 73,000 E. coli infections annually. E. coli is found naturally in animals but is destroyed in meat by thorough cooking. It can also be found in sprouts and lettuce that have not been properly washed.

An E. coli infection can cause diarrhea and, in the very young or very old, further problems or even death. The CDC attributes 61 deaths annually to E. coli.

Salmonella also is linked to eating foods that have not been cooked properly. The illness causes diarrhea, fever and cramps. The CDC receives reports of 40,000 salmonella cases annually.

Taking it for granted

N. Duane Noland is a central Illinois farmer and a Republican state senator. "We have benefited for years in this nation of it being a given that our food was safe. When you see what has happened in Europe it makes you think," he said.

With the amount of international travel coming in to airports like O'Hare International Airport, Noland said it's scary to think how easily something like foot-and-mouth disease could spread if precautions aren't maintained.

"It'd be devastating," he said.

Aside from the economic problems, consumers would have to develop a taste for soy burgers and tofu.

"It'd be tough for us," said Diane Quagliani, a registered dietician in Western Springs and a spokeswoman for the American Dietetic Association. "Meat is certainly a food we enjoy here."

Food safety analyst Ann Hollingsworth said most people take food safety for granted.

"I think they expect a level of food safety that may not be realistic at times. I don't think they realize how much effort goes into the processing of their food whether it is hamburger, steak or lettuce. I don't think they realize the steps it takes to keep that produce safe."

Hollingsworth is a former vice president of food safety for Keystone Foods. Based in the Philadelphia area, Keystone is a meat supplier for many national fast-food chains. Hollingsworth, now based in Carollton, Ga., is a food safety and food crisis management consultant.

She said she's pleased with the steps the U.S. meat industry has taken to prevent either disease here. Because an outbreak would spell financial doom for the industry, Hollingsworth said companies often are ahead of the government in preventing and preparing for the same kinds of catastrophes that have happened in Europe.

With an intimate knowledge of how the industry works and the scares that can lurk behind every corner, Hollingsworth said she doesn't hesitate to sit down to a steak dinner.

"I was born and raised on a cattle farm," she said. "I'm cautious when I travel internationally about what I eat. And I would probably think twice about eating beef in Great Britain."