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From: TSS ()
Research Project: Study of Atypical Bse 2006 Annual Report 4d.Progress report. The aim of the cooperative research project is (i) to compare the U.S. Bovine Spongiform Encephalopathy (BSE) isolates and the atypical BSE isolates identified in Italy and (ii) to determine whether diagnostic methods routinely used at the USDA are able to identify atypical BSE cases. Within FY06, formalin fixed and frozen brain materials from animals with typical and atypical Italian (BASE) BSE have been sent by CEA to the USDA-ARS-NADC laboratory in Ames, IA. The serial brain material sections of BSE and BASE (consecutively numbered) will be analyzed in Ames using the USDA immunohistochemistry (IHC) protocol. To evaluate its reproducibility in Italian laboratories and to standardize the method, the USDA IHC protocol is being established at the CEA neuropathology laboratory. As soon as the Ventana NexES IHC Staining System is available to the CEA, the same samples (different cut numbers) will be examined by the CEA using the CEA in-house and the USDA IHC protocol. In order to evaluate the USDA Western blot method, about 2 gram of typical Italian BSE and about 2 gram of atypical BASE brain tissue have been sent to the USDA-ARS-NADC laboratory. These samples and U.S. typical and atypical BSE samples have been analyzed in parallel using both the USDA and CEA Western blot methods and three different monoclonal antibodies (6H4, P4, SAF 84). These studies were performed during the visit by a CEA collaborator to the USDA-ARS-NADC. The latter studies revealed that both the Italian and USDA extraction and Western blot methods allowed the identification of the typical and atypical BSE samples tested. ATYPICAL BSE BACKGROUND HISTORY USA Research Project: Study of Atypical Bse Location: Virus and Prion Diseases of Livestock Project Number: 3625-32000-073-07 Approach: http://www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=408490 2005 Annual Report Volume 12, Number 12–December 2006 On the Question of Sporadic or Atypical Bovine SpongiformEncephalopathy and Creutzfeldt-Jakob Disease Paul Brown,* Lisa M. McShane,† Gianluigi Zanusso,‡ and Linda Detwiler§ Strategies to investigate the possible existence of sporadic bovine spongiform encephalopathy (BSE) require systematic testing programs to identify cases in countries considered to have little or no risk for orally acquired disease, or to detect a stable occurrence of atypical cases in countries in which orally acquired disease is disappearing. To achieve 95% statistical confidence that the prevalence of sporadic BSE is no greater than 1 per million (i.e., the annual incidence of sporadic Creutzfeldt-Jakob disease [CJD] in humans) would require negative tests in 3 million randomly selected older cattle. A link between BSE and sporadic CJD has been suggested on the basis of laboratory studies but is unsupported by epidemiologic observation. Such a link might yet be established by the discovery of a specific molecular marker or of particular combinations of trends over time of typical and atypical BSE and various subtypes of sporadic CJD, as their numbers are influenced by a continuation of current public health measures that exclude high-risk bovine tissues from the animal and human food chains. Whether humans might be more susceptible to atypical forms of BSE cannot be answered at this time. Experimentally transmitted BASE shows shorter incubation periods than BSE in at least 1 breed of cattle, bovinized transgenic mice, and Cynomolgus monkeys (12,13). In humanized transgenic mice, BASE transmitted, whereas typical BSE did not transmit (13). Paradoxically, the other major phenotype (H) showed an unusually long incubation period in bovinized transgenic mice (12). The limited experimental evidence bearing on a possible relationship between BSE and sporadic CJD is difficult to interpret. The original atypical BASE strain of BSE had a molecular protein signature very similar to that of 1 subtype (type 2 M/V) of sporadic CJD in humans (5). In another study, a strain of typical BSE injected into humanized mice encoding valine at codon 129 showed a glycopattern indistinguishable from the same subtype of sporadic CJD (15). In a third study, the glycopatterns of both the H and L strains of atypical BSE evidently did not resemble any of the known sporadic CJD subtypes (12). To these molecular biology observations can be added the epidemiologic data accumulated during the past 30 years. The hypothesis that at least some cases of apparently sporadic CJD are due to unrecognized BSE infections cannot be formally refuted, but if correct, we might expect by now to have some epidemiologic evidence linking BSE to at least 1 cluster of apparently sporadic cases of CJD. Although only a few clusters have been found (and still fewer published), every proposed cluster that has been investigated has failed to show any common exposure to bovines. For that matter, no common exposure has been shown to any environmental vehicles of infection, including the consumption of foodstuffs from bovine, ovine, and porcine sources, the 3 livestock species known to be susceptible to transmissible spongiform encephalopathies. Additional negative evidence comes from several large case-control studies in which no statistically significant dietary differences were observed between patients with sporadic CJD and controls (16,17). On the other hand, the difficulty of establishing a link between BSE and CJD may be compounded by our ignorance of the infectious parameters of a sporadic form of BSE (e.g., host range, tissue distribution of infectivity, route of transmission, minimum infectious dose for humans, whether single or multiple). Presumably, these parameters would resemble those of variant CJD; that is, high infectivity central nervous system and lymphoreticular tissues of an infected cow find their way into products consumed by humans. Transmissions that might have occurred in the past would be difficult to detect because meat products are generally not distributed in a way that results in detectable geographic clusters. Barring the discovery of a specific molecular signature (as in variant CJD), the most convincing clue to an association will come from the observation of trends over time of the incidence of typical and atypical BSE and of sporadic and variant CJD. With 4 diseases, each of which could have increasing, unchanging, or decreasing trends, there could be 81 (34) possible different combinations. However, it is highly likely that the trends for typical BSE and variant CJD will both decrease in parallel as feed bans continue to interrupt recycled contamination. The remaining combinations are thus reduced to 9 (32), and some of them could be highly informative. For example, if the incidence of atypical BSE declines in parallel with that of typical BSE, its candidacy as a sporadic form of disease would be eliminated (because sporadic disease would not be influenced by current measures to prevent oral infection). If, on the other hand, atypical BSE continues to occur as typical BSE disappears, this would be a strong indication that it is indeed sporadic, and if in addition at least 1 form of what is presently considered as sporadic CJD (such as the type 2 M/V subtype shown to have a Western blot signature like BASE) were to increase, this would suggest (although not prove) a causal relationship (Figure 5). Recognition of the different forms of BSE and CJD depends upon continuing systematic testing for both bovines and humans, but bovine testing will be vulnerable to heavy pressure from industry to dismantle the program as the commercial impact of declining BSE cases ceases to be an issue. Industry should be aware, however, of the implications of sporadic BSE. Its occurrence would necessitate the indefinite retention of all of the public health measures that exclude high-risk bovine tissues from the animal and human food chains, whereas its nonoccurrence would permit tissues that are now destroyed to be used as before, once orally acquired BSE has disappeared. SNIP... Models Qingzhong Kong, Ph.D., Assistant Professor, Pathology, Case Western Reserve Bovine Amyloid Spongiform Encephalopathy (BASE) is an atypical BSE strain 6:30 Close of Day One There is a growing number of human CJD cases, and they were presented last He estimates that it may be up to 14 or 15 persons which display selectively MARCH 26, 2003 RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to comment on the CDC's attempts to monitor the occurrence of emerging forms of CJD. Asante, Collinge et al [1] have reported that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype that is indistinguishable from type 2 PrPSc, the commonest sporadic CJD. However, CJD and all human TSEs are not reportable nationally. CJD and all human TSEs must be made reportable in every state and internationally. I hope that the CDC does not continue to expect us to still believe that the 85%+ of all CJD cases which are sporadic are all spontaneous, without route/source. We have many TSEs in the USA in both animal and man. CWD in deer/elk is spreading rapidly and CWD does transmit to mink, ferret, cattle, and squirrel monkey by intracerebral inoculation. With the known incubation periods in other TSEs, oral transmission studies of CWD may take much longer. Every victim/family of CJD/TSEs should be asked about route and source of this agent. To prolong this will only spread the agent and needlessly expose others. In light of the findings of Asante and Collinge et al, there should be drastic measures to safeguard the medical and surgical arena from sporadic CJDs and all human TSEs. I only ponder how many sporadic CJDs in the USA are type 2 PrPSc? Singeltary, Sr et al. JAMA.2001; 285: 733-734. http://jama.ama-assn.org/ USA BSE OIG 2006 The second case, which was detected last year in a Texas cow and which USDA These two cases (the latest was detected in an Alabama cow) present a "The fact the Texas cow showed up fairly clearly implied the existence of Brown, who is preparing a scientific paper based on the latest two mad cow USDA officials finally retested the cow and confirmed it was infected seven "Everything they did on the Texas cow makes everything USDA did before 2005 PAUL BROWN M.D. http://www.fda.gov/ohrms/dockets/dockets/02n0273/02n-0273-c000490-vol40.pdf [Docket No. 03-025IFA] FSIS Prohibition of the Use of Specified Risk http://www.fsis.usda.gov/OPPDE/Comments/03-025IFA/03-025IFA-2.pdf THE SEVEN SCIENTIST REPORT *** 9 December 2005 SEROLOGICALS CORPORATION http://www.fda.gov/ohrms/dockets/dockets/02n0273/02n-0273-c000383-01-vol35.pdf Embassy of Japan Dockets Entered on December 22, 2005 03-025IFA 03-025IFA-6 Jason Frost [PDF] http://www.fsis.usda.gov/OPPDE/Comments/03-025IF/03-025IF-589.pdf Terry S. Singeltary SR.
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