The Diagnosis of Bovine Spongiform Encephalopathy and Scrapie by the Detection of Fibrils and the Abnormal Protein lsoform

Stack, M.J.; Keyes, P.; Scott, A. C.

doi:10.1385/0-89603-342-2:85

Cited by 17 publications

(14 citation statements)

References 23 publications

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“…Initially, WB protocols were lengthy procedures, with several ultracentrifugation steps needed to purify the PrP Sc . 91 The rapid WB tests have been adapted to omit the ultracentrifugation steps by the use of appropriate homogenization buffers. Following usual electrophoretic separation on polyacrylamide gels and transfer onto membranes, the abnormal PrP protein is detected after incubation with an antibody against the protease-resistant core of the protein, then with a conjugated secondary antibody.…”

Section: Rapid Tests or Screening Testsmentioning

confidence: 99%

Diagnosis of Transmissible Spongiform Encephalopathies in Animals: A Review

Gavier‐Widén

Stack

Baron³

et al. 2005

J VET Diagn Invest

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Abstract. Transmissible spongiform encephalopathies (TSEs) in animals include, among others, bovine spongiform encephalopathy (BSE), scrapie, chronic wasting disease, and atypical forms of prion diseases. Diagnosis of TSEs is based on identification of characteristic lesions or on detection of the abnormal prion proteins in tissues, often by use of their partial proteinase K resistance property. Correctly sampling of target tissues is of utmost importance as this has a considerable effect on test sensitivity. Most of the rapid or screening tests are based on ELISA or Western immunoblot (WB) analysis, and many are officially approved. Confirmatory testing is normally performed by use of histologic examination, immunohistochemical analysis, certain WB protocols, or detection of prion fibrils by use of electron microscopy (scrapie-associated fibril). The discriminatory methods for diagnostic use are mostly based on WB technology and provide initial identification of the prion strain, particularly for differentiation of BSE from scrapie in small ruminants. Definitive prion strain characterization is performed by use of bioassays, usually in mice. A burgeoning number of transgenic mice have been developed for TSE studies. Development of new tests with higher sensitivity and of more reliable diagnostic applications for live animals tested for food safety reasons is a rapidly developing field. Ultimately, the choice of a test for TSE diagnosis depends on the rationale for the testing.

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Section: Rapid Tests or Screening Testsmentioning

confidence: 99%

Diagnosis of Transmissible Spongiform Encephalopathies in Animals: A Review

Gavier‐Widén

Stack

Baron³

et al. 2005

J VET Diagn Invest

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“…A segment of spinal cord (C 1-2 ) was collected and stored at 270˚C for examination for scrapieassociated fibrils (SAF) (Stack et al, 1996). Tissues were also collected into 10 % formal saline (CNS and dorsal root ganglia) or phosphatebuffered, neutral 10 % formalin (BF) (viscera, lymphoreticular tissues, endocrine organs, peripheral nervous system and skeletal muscles) for histopathological examinations.…”

Section: Introductionmentioning

confidence: 99%

Studies of the transmissibility of the agent of bovine spongiform encephalopathy to pigs

Wells

Hawkins

Austin³

et al. 2003

Journal of General Virology

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Studies to test the transmissibility of the bovine spongiform encephalopathy (BSE) agent to pigs began in 1989. Parenteral inoculation of the agent by three routes simultaneously (intracranially, intravenously and intraperitoneally) produced disease with an incubation period range of 69-150 weeks. Pre-clinical pathological changes were detected in two pigs killed electively at 105 and 106 weeks post-inoculation. Infectivity was detected by bioassay in inbred mice in the CNS of those pigs that developed spongiform encephalopathy. Infectivity was also found in the stomach, jejunum, distal ileum and pancreas of terminally affected pigs. These findings show that pigs are susceptible to BSE. In contrast, disease failed to occur in pigs retained for 7 years after exposure by feeding BSE-affected brain on three separate days, at 1-2 week intervals. The amounts fed each day were equivalent to the maximum daily intake of meat and bone meal in rations for pigs aged 8 weeks. No infectivity was found in tissues assayed from the pigs exposed orally. This included tissues of the alimentary tract. It is suggested that these pigs did not become infected. The relatively high oral exposure used in these experiments compared with feed-borne exposure in the field may explain the absence of an epidemic of spongiform encephalopathy in domestic pigs concurrent with the BSE epidemic in the UK.

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“…a The SAFs were detected in fresh brain (caudal medulla) using negative-stain electron microscopy. 19 Genomic DNA was extracted from 3 ml of whole blood or 30 mg of spleen using a commercial kit. b Exon 3 of the bovine PRNP gene was amplified using approximately 0.4 g genomic DNA in a final concentration of each of the following reagents: 2.5 M MgCl 2 , 200 M dNTP stock solution, 2.5 units of Taq polymerase, and 0.2 M each of forward primer (5Ј ggcatatgatgctgacacc) and reverse primer (5Ј tacggggctgcaggtagat).…”

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Experimental Transmission of Chronic Wasting Disease Agent from Mule Deer to Cattle by the Intracerebral Route

et al. 2005

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This communication reports final observations on experimental transmission of chronic wasting disease (CWD) from mule deer to cattle by the intracerebral route. Thirteen calves were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD. Three other calves were kept as uninoculated controls. The experiment was terminated 6 years after inoculation. During that time, abnormal prion protein (PrPres) was demonstrated in the central nervous system (CNS) of 5 cattle by both immunohistochemistry and Western blot. However, microscopic lesions suggestive of spongiform encephalopathy (SE) in the brains of these PrPres-positive animals were subtle in 3 cases and absent in 2 cases. Analysis of the gene encoding bovine PRNP revealed homozygosity for alleles encoding 6 octapeptide repeats, serine (S) at codon 46, and S at codon 146 in all samples. Findings of this study show that although PrPres amplification occurred after direct inoculation into the brain, none of the affected animals had classic histopathologic lesions of SE. Furthermore, only 38% of the inoculated cattle demonstrated amplification of PrPres. Although intracerebral inoculation is an unnatural route of exposure, this experiment shows that CWD transmission in cattle could have long incubation periods (up to 5 years). This finding suggests that oral exposure of cattle to CWD agent, a more natural potential route of exposure, would require not only a much larger dose of inoculum but also may not result in amplification of PrPres within CNS tissues during the normal lifespan of cattle.

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The Diagnosis of Bovine Spongiform Encephalopathy and Scrapie by the Detection of Fibrils and the Abnormal Protein lsoform

Cited by 17 publications

References 23 publications

Diagnosis of Transmissible Spongiform Encephalopathies in Animals: A Review

Diagnosis of Transmissible Spongiform Encephalopathies in Animals: A Review

Studies of the transmissibility of the agent of bovine spongiform encephalopathy to pigs

Experimental Transmission of Chronic Wasting Disease Agent from Mule Deer to Cattle by the Intracerebral Route

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