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Mohamed F, Aboulqassim A, Sharif M, Belgasem S, Omar A, Saeed N. Immunohistochemical study of scrapie in naturally affected sheep in the east of Libya. Open Vet J 2024; 14:1843-1849. [PMID: 39308714 PMCID: PMC11415906 DOI: 10.5455/ovj.2024.v14.i8.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 07/05/2024] [Indexed: 09/25/2024] Open
Abstract
Background The most common natural prion disease that primarily affects sheep and goats is scrapie. It belongs to a group of disorders known as transmissible spongiform encephalopathies, which impact both humans and animals. Aim The research is aimed to examine and confirm the presence of scrapie in Libya using immunohistochemistry (IHC) techniques. Methods Brain samples were collected from thirty-three sheep older than two years of age showing clinical signs resembling to scrapie during the period between 2018 and 2023, regardless of race or gender. Three animals, six months old, healthy, and without any symptoms, were used as negative controls. Different parts of the brain, including the obex and cerebellum, were taken from each case. The IHC technique used in this study involved staining with monoclonal antibody L42 and DAB (3,3'-diaminobenzidine) as a chromogenic substrate. Results The IHC examination showed the expression of prion proteins in brain tissue in twenty-three samples. The staining intensity was markedly observed in the neuronal cell bodies and around blood vessels. Conclusion The findings of this study provide evidence that scrapie exists in Libya.
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Affiliation(s)
- Fawzia Mohamed
- Faculty of Veterinary Medicine, Omar Al-Mukhtar University, Al-Bayda, Libya
| | - Ayiman Aboulqassim
- Faculty of Veterinary Medicine, Omar Al-Mukhtar University, Al-Bayda, Libya
| | - Monier Sharif
- Faculty of Veterinary Medicine, Omar Al-Mukhtar University, Al-Bayda, Libya
| | | | | | - Nagi Saeed
- Agricultural Research Center, Al-Bayda, Libya
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Di Piazza G, Lyytikäinen T, Ru G, Simmons M, Ortiz‐Peláez A. Evaluation of the application of the Czech Republic to be recognised as having a negligible risk of classical scrapie. EFSA J 2023; 21:e08335. [PMID: 37881330 PMCID: PMC10594138 DOI: 10.2903/j.efsa.2023.8335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023] Open
Abstract
The Czech Republic submitted a request to the European Commission to be recognised as a Member State with negligible risk of classical scrapie. EFSA has been asked to assess if the Czech Republic in its application has demonstrated for a period of at least 7 years (2015-2021) and proposed for the future, that a sufficient number of ovine and caprine animals over 18 months of age, representative of slaughtered, culled or found dead on farm animals, have been and will continue to be tested annually to provide a 95% level of confidence of detecting classical scrapie if it is present in that population at a prevalence rate exceeding 0.1%. A risk-based approach using stochastic scenario-tree modelling accounting for surveillance stream and species was applied. There is still a lack of data on the actual performance of the approved tests under field conditions, especially in sheep. Therefore, alternative scenarios were explored extending the range from the sensitivity provided by the past European Union evaluations of diagnostic screening tests to a sensitivity of 50%, consistent with published data obtained under field conditions in infected goat populations. Using data provided by the Czech Republic for 2015-2022, the estimated parameters of the scenario-tree model, the range of values of diagnostic sensitivity and applying the criterion for the 95% confidence level, it is concluded that the Czech Republic has tested annually a sufficient number of small ruminants to meet the requirement, for all combinations of years and diagnostic sensitivity scenarios except for 60% diagnostic sensitivity in 2021 and 2022, and 50% in 2015, 2016 and 2018-2022. Based on the proposed number of samples to be tested in 2023 and future years, the Czech Republic would test a sufficient number of animals to meet the requirement for all combinations of diagnostic sensitivity, except for the 50% scenario.
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Konold T, Spiropoulos J, Thorne J, Phelan L, Fothergill L, Rajanayagam B, Floyd T, Vidana B, Charnley J, Coates N, Simmons M. The Scrapie Prevalence in a Goat Herd Is Underestimated by Using a Rapid Diagnostic Test. Front Bioeng Biotechnol 2020; 8:164. [PMID: 32226784 PMCID: PMC7081731 DOI: 10.3389/fbioe.2020.00164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/18/2020] [Indexed: 11/30/2022] Open
Abstract
Current European surveillance regulations for scrapie, a naturally occurring transmissible spongiform encephalopathy (TSE) or prion disease in sheep and goats, require testing of fallen stock or healthy slaughter animals, and outline measures in the case of confirmation of disease. An outbreak of classical scrapie in a herd with 2500 goats led to the culling of the whole herd, providing the opportunity to examine a subset of goats, take samples, and examine them for the presence of disease-associated prion protein (PrPSc) to provide further information on scrapie test sensitivity, pathology, and association with prion protein genotype. Goats were examined clinically prior to cull, and the brains examined post mortem by Bio-Rad ELISA, a rapid screening test used for active surveillance in sheep and goats, and two confirmatory tests, Western blot and immunohistochemistry. Furthermore, up to 10 lymphoid tissues were examined by immunohistochemistry. Of 151 goats examined, three (2.0%) tested positive for scrapie by ELISA on brain, confirmed by confirmatory tests, and a further five (3.3%) were negative by ELISA but positive by at least one of the confirmatory tests. Only two of these, both positive by ELISA, displayed evident signs of scrapie. In addition, 10 (6.6%) goats, which also included two clinical suspects, were negative on brain examination but had detectable PrPSc in lymphoid tissue. PrPSc was detected most frequently in the medial retropharyngeal lymph node (LN; 94.4% of all 18 cases) and palatine tonsil (88.9%). Abnormal behavior and circling or loss of balance when blindfolded were the best clinical discriminators for scrapie status. None of the goats that carried a single allele in the prion protein gene associated with increased resistance to scrapie (Q211, K222, S146) were scrapie-positive, and the percentage of goats with these alleles was greater than expected from previous surveys. Significantly more goats that were scrapie-positive were isoleucine homozygous at codon 142 (II142). The results indicate that the sensitivity of the applied screening test is poor in goats compared to the confirmatory tests as gold standard, particularly for asymptomatic animals. Sensitivity of surveillance could be improved by testing retropharyngeal LN or palatine tonsil in addition to brain.
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Affiliation(s)
- Timm Konold
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - John Spiropoulos
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Jemma Thorne
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Laura Phelan
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Louise Fothergill
- Central Sequencing Unit, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Brenda Rajanayagam
- Department of Epidemiological Sciences, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Tobias Floyd
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Beatriz Vidana
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
| | - Judith Charnley
- Animal and Plant Health England Field Delivery, Skipton, United Kingdom
| | - Nadya Coates
- TSE/BVDV Testing Laboratory, Eurofins Forensic Services, Risley, United Kingdom
| | - Marion Simmons
- Pathology Department, Animal and Plant Health Agency Weybridge, Addlestone, United Kingdom
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Simmons MM, Thorne L, Ortiz-Pelaez A, Spiropoulos J, Georgiadou S, Papasavva-Stylianou P, Andreoletti O, Hawkins SA, Meloni D, Cassar C. Transmissible spongiform encephalopathy in goats: is PrP rapid test sensitivity affected by genotype? J Vet Diagn Invest 2020; 32:87-93. [PMID: 31894737 PMCID: PMC7003235 DOI: 10.1177/1040638719896327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Transmissible spongiform encephalopathy (TSE) surveillance in goats relies on tests initially approved for cattle, subsequently assessed for sheep, and approval extrapolated for use in "small ruminants." The current EU-approved immunodetection tests employ antibodies against various epitopes of the prion protein PrPSc, which is encoded by the host PRNP gene. The caprine PRNP gene is polymorphic, mostly at codons different from the ovine PRNP. The EU goat population is much more heterogeneous than the sheep population, with more PRNP-related polymorphisms, and with marked breed-related differences. The ability of the current tests to detect disease-specific PrPSc generated against these different genetic backgrounds is currently assumed, rather than proven. We examined whether common polymorphisms within the goat PRNP gene might have any adverse effect on the relative performance of EU-approved rapid tests. The sample panel comprised goats from the UK, Cyprus, France, and Italy, with either experimental or naturally acquired scrapie at both the preclinical and/or unknown and clinical stages of disease. Test sensitivity was significantly lower and more variable when compared using samples from animals that were preclinical or of unknown status. However, all of the rapid tests included in our study were able to correctly identify all samples from animals in the clinical stages of disease, apart from samples from animals polymorphic for serine or aspartic acid at codon 146, in which the performance of the Bio-Rad tests was profoundly affected. Our data show that some polymorphisms may adversely affect one test and not another, as well as underline the dangers of extrapolating from other species.
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Affiliation(s)
- Marion M. Simmons
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Leigh Thorne
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Angel Ortiz-Pelaez
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - John Spiropoulos
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Soteria Georgiadou
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Penelope Papasavva-Stylianou
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Olivier Andreoletti
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Stephen A.C. Hawkins
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Daniela Meloni
- APHA-Weybridge, Addlestone, Surrey, UK (Simmons, Thorne, Spiropoulos, Hawkins, Cassar)
- Unit of Biological Hazards and Contaminants (BIOCONTAM), Risk Assessment & Scientific Assistance, European Food Safety Authority (EFSA), Parma, Italy (Ortiz-Pelaez)
- Veterinary Services of Cyprus, Nicosia, Cyprus (Georgiadou, Papasavva-Stylianou)
- UMR Institut National de la Recherche Agronomique, École Nationale Vétérinaire de Toulouse, Toulouse, France (Andreoletti)
- Italian Reference Laboratory for TSEs, Istituto Zooprofilattico Sperimentale del Piemonte, Turin, Italy (Meloni)
| | - Claire Cassar
- Claire Cassar, Department of Pathology, APHA-Weybridge, Woodham Lane, Addlestone, Surrey, KT15 3NB, UK.
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