Report on the epidemiological investigation of a BSE case in Scotland (RBSE24_00003) United Kingdom October 2024
Executive summary
On 9 May 2024, Scotland’s Chief Veterinary Officer (CVO) confirmed a case of classical bovine spongiform encephalopathy (BSE) in a 7.5-year-old cow on a beef suckler farm in Ayrshire, Scotland. This was the first case of classical BSE to be confirmed in the United Kingdom (UK) since 2021, and in Scotland since 2018. This report summarises the epidemiological investigations that have been carried out to describe and understand this single case of BSE.
The index case was a Simmental cross cow, born on 18 October 2016 in a holding in Dumfries and Galloway, Scotland. It was purchased and introduced into the incident herd on 27 June 2018, where it resided until its death.
The index case died on farm on 26 April 2024. The farmer did not suspect notifiable disease and the carcass was collected by the fallen stock company on the same day. The carcass was tested for BSE as per the UK’s statutory BSE surveillance procedures due to the cow’s age and because she was fallen stock.
A preliminary positive result was received on 1 May 2024. A final positive result was confirmed on 9 May 2024 by the Animal and Plant Health Agency (APHA) Weybridge. APHA Weybridge is the UK National Reference Laboratory (NRL) for transmissible spongiform encephalopathies (TSEs). It is also the World Organisation for Animal Health (WOAH) Reference Laboratory for BSE and scrapie.
Tracing investigations identified 2 offspring born in the 24 months prior to the clinical onset of disease and death of the index case (see also appendix 2, point (f)):
• The first one had a date of birth (DOB) of 13 May 2023. It was alive at the time of confirmation and placed under restrictions following BSE confirmation in the index case. It was transported alive to the NRL for TSEs in Weybridge for clinical observation. It was then euthanised and underwent a postmortem examination and BSE testing, with negative results.
• The second one had a DOB of 21 May 2022. It was already dead (slaughtered for human consumption and not eligible for BSE testing) when traced after the BSE case was confirmed.
Tracings investigations also identified 45 cohort animals born and/or reared with the index case during the relevant risk period (12 months either side of the date of birth of this case).
Of these, 43 were restricted and humanely culled on farm at their respective locations.
The carcasses were sampled for BSE testing and then disposed of as category 1 animal by products (ABP) at an approved ABP rendering facility. All the samples returned negative results for BSE.
The remaining 2 cohort animals were already dead when traced after the BSE case was confirmed. (They were slaughtered for human consumption and not tested for BSE as they were not eligible.)
2
Epidemiological investigations were undertaken at both the holding of birth and the holding of death of the positive BSE case. Following these investigations, the most likely source of infection remains undetermined. Four potential risk pathways were identified and assessed as very low likelihood events, all with high uncertainty. These 4 potential risk pathways were:
• accidental exposure to contaminated feed (possibly feed delivered before the reinforced feed ban that had remained attached to the side walls of a feed silo decommissioned in 2017) (see also appendix 2, point (b))
• maternal transmission
• environmental source 1: exposure to previous potential presence of the BSE agent on the natal farm via birth products
• environmental source 2: exposure to previous potential presence of the BSE agent on the natal farm from on farm or local cattle burials (when it was still legal to do so before 1 May 2003) via contaminated groundwater or other pathways (see also appendix 2, point (c))
The likelihood of any other potential risk pathways has been assessed as negligible. Any identified sources of infection have been effectively controlled through the following measures:
• The positive animal died on farm and was not destined to enter the food chain. As fallen stock, the entire carcass was category 1 ABP and was appropriately disposed of.
• Rearing cohorts and offspring cohorts were traced, culled and disposed of. All those culled cohorts and offspring were tested for BSE with negative results.
• Surveillance and testing of at-risk animals and fallen stock (see appendix 2, point D).
• Elimination of animal proteins from cattle feed as primary route of transmission (reinforced feed ban in effect since August 1996, see appendix 2, point B).
• Effective disposal of specified risk material (SRM) as per legislative requirements (see appendix 2, point E).
• Ban on burying fallen stock (dead animals) on farms since 1 May 2003 (see appendix 2, point C).
• The old feed silo was decommissioned in 2017.
The implementation of these control measures ensures that the risk of BSE agents being recycled within the bovine population has remained negligible. There is no evidence or other cause for concern that statutory official BSE or feed controls have been breached at any point in relation to this case or its herd of origin.
The detection of this case is evidence that the UK surveillance system for detecting and containing BSE is robust and effective. There is no threat to food safety, to human health or to animal health as a consequence of this case.
3
Introduction
snip...
K – Spontaneous origin
According to EFSA opinion, ‘the classification of a case as spontaneous is circumstantial and may change over time subject to additional information. It does not infer that there is no external cause; just that it could not be ascertained. A case of disease is classified as spontaneous by a process of elimination, excluding all other definable possibilities.’ (Ricci and others, 2017.)
As not all other pathways have been excluded, the likelihood of spontaneous origin is assessed as negligible.
Medium uncertainty reflects that the highest likelihood of any other pathways has been assessed as ‘very low, with high uncertainty’.
Pathway assessment Negligible likelihood, medium uncertainty.
snip...
Concluding remarks
Following an epidemiological investigation, 4 potential risk pathways have been identified as most likely source of infection. Each are assessed as a very low likelihood event, with high uncertainty.
1. Potential accidental exposure to contaminated feed concentrates at natal farm (old feed remnants of potentially contaminated feed – before the total feed ban in 1996– that might have remained in silo 1 and that could have accidentally been released in 2017).
2. Potential maternal transmission.
3. Environmental source
1: Potential exposure to previous potential presence of BSE on natal farm via birth products.
4. Environmental source
2: Potential exposure to previous potential presence of BSE on natal farm from on farm or local cattle burials via contaminated groundwater or other pathways.
The likelihood of any other potential risk pathways has been assessed as negligible.
The detection of this case is evidence that the surveillance system for detecting and containing BSE is solid and effective. There is no threat to food safety, to human health or to animal health as a consequence of this case. The implementation of control measures and continuous monitoring ensures that the risk of BSE agents being recycled within the bovine population has remained negligible. There is no evidence that any TSE regulations have been breached in this case. There is every reason to believe that current actions will contain any further potential exposure to cattle or the human food chain.
Acknowledgements
The views expressed in this report are those of the National Emergency Epidemiology Group (NEEG). We would like to express our thanks to the TSE experts within APHA, members of the One Health Team and the many other APHA colleagues who have assisted with this investigation. The NEEG is comprised of staff from APHA’s Veterinary, Operations and Science Directorates.
snip...see full report;
Scotland Single case of disease confirmed in Dumfries and Galloway
Published 06 December 2024 12:45
Topic Farming and rural
Single case of disease confirmed in Dumfries and Galloway.
A case of atypical Bovine Spongiform Encephalopathy (BSE) has been confirmed in a cow on a farm in Dumfries and Galloway.
Precautionary movement restrictions have been put in place at impacted premises and cover animals which have been in contact with the case. Further investigations to identify the origin of the disease are ongoing. This is standard procedure for a confirmed case of atypical BSE.
The case was identified as a result of our routine yet intensive BSE surveillance and stringent control measures are in place. Atypical BSE is not known to be a risk to public health and the animal did not enter the human food chain. Food Standards Scotland have confirmed there is no risk to human health as a result of this isolated case.
The owners of the affected animals are working with authorities on next steps.
Agriculture Minister Jim Fairlie said:
“Following confirmation of a case of atypical BSE in Dumfries and Galloway, the Scottish Government and other agencies took swift and robust action to protect the agriculture sector.
“The fact we identified this isolated case so quickly is proof that our surveillance system for detecting this type of disease is working effectively.
“I want to thank the animal’s owner for their diligence. Their decisive action has allowed us to identify and isolate the case at speed which has minimised its impact on the wider industry."
Chief Veterinary Officer Sheila Voas said:
“The fast detection of this case is proof that our surveillance system is doing its job.
“We are working closely with the Animal and Plant Health Agency, and other partners to identify where the disease came from.
“I want to reassure both farmers and the public that this is an isolated case and of the aytypical strain of BSE which is not transmissible and not connected to contaminated feed. But, if any farmers are concerned, I would urge them to seek veterinary advice."
Ian McWatt, Deputy Chief Executive of Food Standards Scotland said:
“There are strict controls in place to protect consumers from the risk of BSE and consumers can be reassured that these important protection measures remain in place and that Food Standards Scotland Official Veterinarians and Meat Hygiene Inspectors working in all abattoirs in Scotland will continue to ensure that in respect of BSE controls, the safety of consumers remains a priority.
“We will continue to work closely with Scottish Government, other agencies and industry at this time.”
Background
Bovine spongiform encephalopathy (BSE): how to spot and report the disease - gov.scot
The Animal Plant and Health Agency (APHA) is investigating the source of the disease.
All animals over four years of age that die on farm are routinely tested for BSE under our comprehensive surveillance system. Whilst the disease is not directly transmitted from animal to animal, its cohorts, including offspring, have been traced and isolated, and will be destroyed in line with our legal requirements.
In addition to the measures we have in place for fallen stock and animal feed, there is a strict control regime to protect consumers. This includes the removal of specified risk material such as the spinal column, brain and skull from carcasses destined for human consumption.
https://www.gov.scot/news/bse-2/
Published 06 December 2024 12:45
Topic Farming and rural
Single case of disease confirmed in Dumfries and Galloway.
A case of atypical Bovine Spongiform Encephalopathy (BSE) has been confirmed in a cow on a farm in Dumfries and Galloway.
Precautionary movement restrictions have been put in place at impacted premises and cover animals which have been in contact with the case. Further investigations to identify the origin of the disease are ongoing. This is standard procedure for a confirmed case of atypical BSE.
The case was identified as a result of our routine yet intensive BSE surveillance and stringent control measures are in place. Atypical BSE is not known to be a risk to public health and the animal did not enter the human food chain. Food Standards Scotland have confirmed there is no risk to human health as a result of this isolated case.
The owners of the affected animals are working with authorities on next steps.
Agriculture Minister Jim Fairlie said:
“Following confirmation of a case of atypical BSE in Dumfries and Galloway, the Scottish Government and other agencies took swift and robust action to protect the agriculture sector.
“The fact we identified this isolated case so quickly is proof that our surveillance system for detecting this type of disease is working effectively.
“I want to thank the animal’s owner for their diligence. Their decisive action has allowed us to identify and isolate the case at speed which has minimised its impact on the wider industry."
Chief Veterinary Officer Sheila Voas said:
“The fast detection of this case is proof that our surveillance system is doing its job.
“We are working closely with the Animal and Plant Health Agency, and other partners to identify where the disease came from.
“I want to reassure both farmers and the public that this is an isolated case and of the aytypical strain of BSE which is not transmissible and not connected to contaminated feed. But, if any farmers are concerned, I would urge them to seek veterinary advice."
Ian McWatt, Deputy Chief Executive of Food Standards Scotland said:
“There are strict controls in place to protect consumers from the risk of BSE and consumers can be reassured that these important protection measures remain in place and that Food Standards Scotland Official Veterinarians and Meat Hygiene Inspectors working in all abattoirs in Scotland will continue to ensure that in respect of BSE controls, the safety of consumers remains a priority.
“We will continue to work closely with Scottish Government, other agencies and industry at this time.”
Background
Bovine spongiform encephalopathy (BSE): how to spot and report the disease - gov.scot
The Animal Plant and Health Agency (APHA) is investigating the source of the disease.
All animals over four years of age that die on farm are routinely tested for BSE under our comprehensive surveillance system. Whilst the disease is not directly transmitted from animal to animal, its cohorts, including offspring, have been traced and isolated, and will be destroyed in line with our legal requirements.
In addition to the measures we have in place for fallen stock and animal feed, there is a strict control regime to protect consumers. This includes the removal of specified risk material such as the spinal column, brain and skull from carcasses destined for human consumption.
https://www.gov.scot/news/bse-2/
News BSE Published 10 May 2024 10:30 Topic Farming and rural Disease confirmed in Ayrshire.
A case of classical Bovine Spongiform Encephalopathy (BSE) has been confirmed on a farm in Ayrshire.
Precautionary movement restrictions have been put in place at impacted premises and cover animals which have been in contact with the case. Further investigations to identify the origin of the disease are ongoing. This is standard procedure for a confirmed case of classical BSE.
The case was identified as a result of routine surveillance and stringent control measures. The animal did not enter the human food chain. Food Standards Scotland have confirmed there is no risk to human health as a result of this isolated case.
The owners of the affected animals are working with authorities on next steps.
Read more: BSE: how to spot and report the disease. Agriculture Minister Jim Fairlie said:
“Following confirmation of a case of classical BSE in Ayrshire, the Scottish Government and other agencies took swift and robust action to protect the agriculture sector. This included establishing a precautionary movement ban on the farm.
“The fact we identified this isolated case so quickly is proof that our surveillance system for detecting this type of disease is working effectively.
“I want to thank the animal’s owner for their diligence. Their decisive action has allowed us to identify and isolate the case at speed which has minimised its impact on the wider industry."
Chief Veterinary Officer Sheila Voas said:
“The fast detection of this case is proof that our surveillance system is doing its job.
“We are working closely with the Animal and Plant Health Agency, and other partners to identify where the disease came from.
“I want to reassure both farmers and the public that the risk associated with this isolated case is minimal. But, if any farmers are concerned, I would urge them to seek veterinary advice."
Ian McWatt, Deputy Chief Executive of Food Standards Scotland said:
“There are strict controls in place to protect consumers from the risk of BSE, including controls on animal feed, and removal of the parts of cattle most likely to carry BSE infectivity.
“Consumers can be reassured that these important protection measures remain in place and that Food Standards Scotland Official Veterinarians and Meat Hygiene Inspectors working in all abattoirs in Scotland will continue to ensure that in respect of BSE controls, the safety of consumers remains a priority.
“We will continue to work closely with Scottish Government, other agencies and industry at this time.”
Background
The Animal Plant and Health Agency (APHA) is investigating the source of the outbreak.
All animals over four years of age that die on farm are routinely tested for BSE under our comprehensive surveillance system. Whilst the disease is not directly transmitted from animal to animal, its cohorts, including offspring, have been traced and isolated, and will be destroyed in line with our legal requirements.
In addition to the measures we have in place for fallen stock and animal feed, there is a strict control regime to protect consumers. This includes the removal of specified risk material such as the spinal column, brain and skull from carcasses destined for human consumption.
Movement restrictions have also been put in place at three further farms – the farm of the animal’s origin and two more holdings where animals that have had access to the same feed are.
The European Union summary report on surveillance for the presence of transmissible spongiform encephalopathies (TSE) in 2023
Published: 28 November 2024
Adopted: 29 October 2024
DOI https://doi.org/10.2903/j.efsa.2024.9097
KEYWORDS atypical, BSE, classical, CWD, scrapie, surveillance, TSE
CONTACT biohaw@efsa.europa.eu
Abstract
This report presents the results of surveillance on transmissible spongiform encephalopathies in cattle, sheep, goats, cervids and other species, and genotyping in sheep and goats, carried out in 2023 by 27 Member States (MS, EU27), the United Kingdom (in respect of Northern Ireland, (XI)) and other eight non‐EU reporting countries: Bosnia and Herzegovina, Iceland, Montenegro, North Macedonia, Norway, Serbia, Switzerland (the data reported by Switzerland include those of Liechtenstein) and Türkiye. In total, 948,165 cattle were tested by EU27 and XI (−3%, compared with 2022), with five atypical BSE cases reported (four H‐type: two in Spain, one in France and one in Ireland; one L‐type in the Netherlands); and 46,096 cattle by eight non‐EU reporting countries with two atypical BSE cases reported by Switzerland. Three additional atypical BSE cases were reported by UK (1), USA (1) and Brazil (1). In total, 284,686 sheep and 102,646 goats were tested in the EU27 and XI (−3.5% and −5.9%, respectively, compared to 2022). In the other non‐EU reporting countries 26,047 sheep and 589 goats were tested. In sheep, 538 cases of scrapie were reported by 14 MS and XI: 462 classical scrapie (CS) by 4 MS (104 index cases (IC) with genotypes of susceptible groups in 93.4% of the cases), 76 atypical scrapie (AS) (76 IC) by 12 MS. In the other non‐EU reporting countries, Iceland reported 70 cases of CS while Norway reported 7 cases of ovine AS. Ovine random genotyping was reported by six MS and genotypes of susceptible groups accounted for 6.9%. In goats, 183 cases of scrapie were reported, all from EU MS: 176 CS (47 IC) by seven MS and 7 AS (7 IC) by five MS. Three cases in Cyprus and one in Spain were reported in goats carrying heterozygous alleles at codon 146 and 222, respectively. In total, 2096 cervids were tested for chronic wasting disease by ten MS, none tested positive. Norway tested 14,224 cervids with one European moose positive.
© European Food Safety Authority
https://www.efsa.europa.eu/en/efsajournal/pub/9097
Published: 28 November 2024
Adopted: 29 October 2024
DOI https://doi.org/10.2903/j.efsa.2024.9097
KEYWORDS atypical, BSE, classical, CWD, scrapie, surveillance, TSE
CONTACT biohaw@efsa.europa.eu
Abstract
This report presents the results of surveillance on transmissible spongiform encephalopathies in cattle, sheep, goats, cervids and other species, and genotyping in sheep and goats, carried out in 2023 by 27 Member States (MS, EU27), the United Kingdom (in respect of Northern Ireland, (XI)) and other eight non‐EU reporting countries: Bosnia and Herzegovina, Iceland, Montenegro, North Macedonia, Norway, Serbia, Switzerland (the data reported by Switzerland include those of Liechtenstein) and Türkiye. In total, 948,165 cattle were tested by EU27 and XI (−3%, compared with 2022), with five atypical BSE cases reported (four H‐type: two in Spain, one in France and one in Ireland; one L‐type in the Netherlands); and 46,096 cattle by eight non‐EU reporting countries with two atypical BSE cases reported by Switzerland. Three additional atypical BSE cases were reported by UK (1), USA (1) and Brazil (1). In total, 284,686 sheep and 102,646 goats were tested in the EU27 and XI (−3.5% and −5.9%, respectively, compared to 2022). In the other non‐EU reporting countries 26,047 sheep and 589 goats were tested. In sheep, 538 cases of scrapie were reported by 14 MS and XI: 462 classical scrapie (CS) by 4 MS (104 index cases (IC) with genotypes of susceptible groups in 93.4% of the cases), 76 atypical scrapie (AS) (76 IC) by 12 MS. In the other non‐EU reporting countries, Iceland reported 70 cases of CS while Norway reported 7 cases of ovine AS. Ovine random genotyping was reported by six MS and genotypes of susceptible groups accounted for 6.9%. In goats, 183 cases of scrapie were reported, all from EU MS: 176 CS (47 IC) by seven MS and 7 AS (7 IC) by five MS. Three cases in Cyprus and one in Spain were reported in goats carrying heterozygous alleles at codon 146 and 222, respectively. In total, 2096 cervids were tested for chronic wasting disease by ten MS, none tested positive. Norway tested 14,224 cervids with one European moose positive.
© European Food Safety Authority
https://www.efsa.europa.eu/en/efsajournal/pub/9097
The European Union summary report on surveillance for the presence of transmissible spongiform encephalopathies (TSE) in 2022
European Food Safety Authority (EFSA)
First published: 28 November 2023
https://doi.org/10.2903/j.efsa.2023.8384
European Food Safety Authority (EFSA)
First published: 28 November 2023
https://doi.org/10.2903/j.efsa.2023.8384
Approved: 19 October 2023 Abstract
This report presents the results of surveillance on transmissible spongiform encephalopathies (TSE) in cattle, sheep, goats, cervids and other species, and genotyping in sheep and goats, carried out in 2022 by 27 Member States (MS, EU27), the United Kingdom (in respect of Northern Ireland [XI]) and other eight non-EU reporting countries: Bosnia and Herzegovina, Iceland, Montenegro, North Macedonia, Norway, Serbia, Switzerland and Türkiye. In total, 977,008 cattle were tested by EU27 and XI (−4.3%, compared with 2021), and 52,395 cattle by eight non-EU reporting countries, with one case of H-BSE in France. In total, 295,145 sheep and 109,074 goats were tested in the EU27 and XI (−5.2% and −7.9%, respectively, compared to 2021). In the other non-EU reporting countries, 25,535 sheep and 633 goats were tested. In sheep, 557 cases of scrapie were reported by 17 MS and XI: 480 classical scrapie (CS) by five MS (93 index cases [IC] with genotypes of susceptible groups in 97.6% of the cases), 77 atypical scrapie (AS) (76 IC) by 14 MS and XI. In the other non-EU reporting countries, Norway reported 16 cases of ovine AS. Ovine random genotyping was reported by eight MS and genotypes of susceptible groups accounted for 7.3%. In goats, 224 cases of scrapie were reported, all from EU MS: 216 CS (42 IC) by six MS, and 8 AS (8 IC) by four MS. In Cyprus, two cases of CS were reported in goats carrying the heterozygous DN146 allele. In total, 3202 cervids were tested for chronic wasting disease by 10 MS. One wild European moose tested positive in Finland. Norway tested 17,583 cervids with two European moose, one reindeer and one red deer positive. In total, 154 animals from four other species tested negative in Finland.
https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2023.8384
This report presents the results of surveillance on transmissible spongiform encephalopathies (TSE) in cattle, sheep, goats, cervids and other species, and genotyping in sheep and goats, carried out in 2022 by 27 Member States (MS, EU27), the United Kingdom (in respect of Northern Ireland [XI]) and other eight non-EU reporting countries: Bosnia and Herzegovina, Iceland, Montenegro, North Macedonia, Norway, Serbia, Switzerland and Türkiye. In total, 977,008 cattle were tested by EU27 and XI (−4.3%, compared with 2021), and 52,395 cattle by eight non-EU reporting countries, with one case of H-BSE in France. In total, 295,145 sheep and 109,074 goats were tested in the EU27 and XI (−5.2% and −7.9%, respectively, compared to 2021). In the other non-EU reporting countries, 25,535 sheep and 633 goats were tested. In sheep, 557 cases of scrapie were reported by 17 MS and XI: 480 classical scrapie (CS) by five MS (93 index cases [IC] with genotypes of susceptible groups in 97.6% of the cases), 77 atypical scrapie (AS) (76 IC) by 14 MS and XI. In the other non-EU reporting countries, Norway reported 16 cases of ovine AS. Ovine random genotyping was reported by eight MS and genotypes of susceptible groups accounted for 7.3%. In goats, 224 cases of scrapie were reported, all from EU MS: 216 CS (42 IC) by six MS, and 8 AS (8 IC) by four MS. In Cyprus, two cases of CS were reported in goats carrying the heterozygous DN146 allele. In total, 3202 cervids were tested for chronic wasting disease by 10 MS. One wild European moose tested positive in Finland. Norway tested 17,583 cervids with two European moose, one reindeer and one red deer positive. In total, 154 animals from four other species tested negative in Finland.
https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2023.8384
''H-TYPE BSE AGENT IS TRANSMISSIBLE BY THE ORONASAL ROUTE''
This study demonstrates that the H-type BSE agent is transmissible by the oronasal route. These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
https://www.ars.usda.gov/research/publications/publication/?seqNo115=353094
This study demonstrates that the H-type BSE agent is transmissible by the oronasal route. These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
https://www.ars.usda.gov/research/publications/publication/?seqNo115=353094
OIE Conclusions on transmissibility of atypical BSE among cattle
Given that cattle have been successfully infected by the oral route, at least for L-BSE, it is reasonable to conclude that atypical BSE is potentially capable of being recycled in a cattle population if cattle are exposed to contaminated feed. In addition, based on reports of atypical BSE from several countries that have not had C-BSE, it appears likely that atypical BSE would arise as a spontaneous disease in any country, albeit at a very low incidence in old cattle. In the presence of livestock industry practices that would allow it to be recycled in the cattle feed chain, it is likely that some level of exposure and transmission may occur. As a result, since atypical BSE can be reasonably considered to pose a potential background level of risk for any country with cattle, the recycling of both classical and atypical strains in the cattle and broader ruminant populations should be avoided.
https://www.oie.int/fileadmin/SST/adhocreports/Bovine%20spongiform%20encephalopathy/AN/A_AhG_BSEsurv_RiskAss_Mar2019.pdf
Given that cattle have been successfully infected by the oral route, at least for L-BSE, it is reasonable to conclude that atypical BSE is potentially capable of being recycled in a cattle population if cattle are exposed to contaminated feed. In addition, based on reports of atypical BSE from several countries that have not had C-BSE, it appears likely that atypical BSE would arise as a spontaneous disease in any country, albeit at a very low incidence in old cattle. In the presence of livestock industry practices that would allow it to be recycled in the cattle feed chain, it is likely that some level of exposure and transmission may occur. As a result, since atypical BSE can be reasonably considered to pose a potential background level of risk for any country with cattle, the recycling of both classical and atypical strains in the cattle and broader ruminant populations should be avoided.
https://www.oie.int/fileadmin/SST/adhocreports/Bovine%20spongiform%20encephalopathy/AN/A_AhG_BSEsurv_RiskAss_Mar2019.pdf
Annex 7 (contd) AHG on BSE risk assessment and surveillance/March 2019
34 Scientific Commission/September 2019
3. Atypical BSE
The Group discussed and endorsed with minor revisions an overview of relevant literature on the risk of atypical BSE being recycled in a cattle population and its zoonotic potential that had been prepared ahead of the meeting by one expert from the Group. This overview is provided as Appendix IV and its main conclusions are outlined below. With regard to the risk of recycling of atypical BSE, recently published research confirmed that the L-type BSE prion (a type of atypical BSE prion) may be orally transmitted to calves1 . In light of this evidence, and the likelihood that atypical BSE could arise as a spontaneous disease in any country, albeit at a very low incidence, the Group was of the opinion that it would be reasonable to conclude that atypical BSE is potentially capable of being recycled in a cattle population if cattle were to be exposed to contaminated feed. Therefore, the recycling of atypical strains in cattle and broader ruminant populations should be avoided.
The Group acknowledged the challenges in demonstrating the zoonotic transmission of atypical strains of BSE in natural exposure scenarios. Overall, the Group was of the opinion that, at this stage, it would be premature to reach a conclusion other than that atypical BSE poses a potential zoonotic risk that may be different between atypical strains.
4. Definitions of meat-and-bone meal (MBM) and greaves
snip...
REFERENCES
SNIP...END SEE FULL TEXT;
http://web.oie.int/downld/PROC2020/A_SCAD_Sept2019.pdf
34 Scientific Commission/September 2019
3. Atypical BSE
The Group discussed and endorsed with minor revisions an overview of relevant literature on the risk of atypical BSE being recycled in a cattle population and its zoonotic potential that had been prepared ahead of the meeting by one expert from the Group. This overview is provided as Appendix IV and its main conclusions are outlined below. With regard to the risk of recycling of atypical BSE, recently published research confirmed that the L-type BSE prion (a type of atypical BSE prion) may be orally transmitted to calves1 . In light of this evidence, and the likelihood that atypical BSE could arise as a spontaneous disease in any country, albeit at a very low incidence, the Group was of the opinion that it would be reasonable to conclude that atypical BSE is potentially capable of being recycled in a cattle population if cattle were to be exposed to contaminated feed. Therefore, the recycling of atypical strains in cattle and broader ruminant populations should be avoided.
The Group acknowledged the challenges in demonstrating the zoonotic transmission of atypical strains of BSE in natural exposure scenarios. Overall, the Group was of the opinion that, at this stage, it would be premature to reach a conclusion other than that atypical BSE poses a potential zoonotic risk that may be different between atypical strains.
4. Definitions of meat-and-bone meal (MBM) and greaves
snip...
REFERENCES
SNIP...END SEE FULL TEXT;
http://web.oie.int/downld/PROC2020/A_SCAD_Sept2019.pdf
Consumption of L-BSE–contaminated feed may pose a risk for oral transmission of the disease agent to cattle.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324790/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324790/
Thus, it is imperative to maintain measures that prevent the entry of tissues from cattle possibly infected with the agent of L-BSE into the food chain.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310119/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310119/
We recently observed the direct transmission of a natural classical scrapie isolate to macaque after a 10-year silent incubation period, with features similar to some reported for human cases of sporadic CJD, albeit requiring fourfold longe incubation than BSE. Scrapie, as recently evoked in humanized mice (Cassard, 2014), is the third potentially zoonotic PD (with BSE and L-type BSE), thus questioning the origin of human sporadic cases. We will present an updated panorama of our different transmission studies and discuss the implications of such extended incubation periods on risk assessment of animal PD for human health.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019500/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019500/
2.3.2. New evidence on the zoonotic potential of atypical BSE and atypical scrapie prion strains
Olivier Andreoletti, INRA Research Director, Institut National de la Recherche Agronomique (INRA) – École Nationale Vétérinaire de Toulouse (ENVT), invited speaker, presented the results of two recently published scientific articles of interest, of which he is co-author:
‘Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice’ (MarinMoreno et al., 2020) and ‘The emergence of classical BSE from atypical/Nor98 scrapie’ (Huor et al., 2019).
In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.
https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/sp.efsa.2020.EN-1946
Olivier Andreoletti, INRA Research Director, Institut National de la Recherche Agronomique (INRA) – École Nationale Vétérinaire de Toulouse (ENVT), invited speaker, presented the results of two recently published scientific articles of interest, of which he is co-author:
‘Radical Change in Zoonotic Abilities of Atypical BSE Prion Strains as Evidenced by Crossing of Sheep Species Barrier in Transgenic Mice’ (MarinMoreno et al., 2020) and ‘The emergence of classical BSE from atypical/Nor98 scrapie’ (Huor et al., 2019).
In the first experimental study, H-type and L-type BSE were inoculated into transgenic mice expressing all three genotypes of the human PRNP at codon 129 and into adapted into ARQ and VRQ transgenic sheep mice. The results showed the alterations of the capacities to cross the human barrier species (mouse model) and emergence of sporadic CJD agents in Hu PrP expressing mice: type 2 sCJD in homozygous TgVal129 VRQ-passaged L-BSE, and type 1 sCJD in homozygous TgVal 129 and TgMet129 VRQ-passaged H-BSE.
https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/sp.efsa.2020.EN-1946
This study demonstrates that the H-type BSE agent is transmissible by the oronasal route. These results reinforce the need for ongoing surveillance for classical and atypical BSE to minimize the risk of potentially infectious tissues entering the animal or human food chains.
https://www.ars.usda.gov/research/publications/publication/?seqNo115=353094
https://www.ars.usda.gov/research/publications/publication/?seqNo115=353094
***Moreover, sporadic disease has never been observed in breeding colonies or primate research laboratories, most notably among hundreds of animals over several decades of study at the National Institutes of Health25, and in nearly twenty older animals continuously housed in our own facility.***
Even if the prevailing view is that sporadic CJD is due to the spontaneous formation of CJD prions, it remains possible that its apparent sporadic nature may, at least in part, result from our limited capacity to identify an environmental origin.
https://www.nature.com/articles/srep11573
Even if the prevailing view is that sporadic CJD is due to the spontaneous formation of CJD prions, it remains possible that its apparent sporadic nature may, at least in part, result from our limited capacity to identify an environmental origin.
https://www.nature.com/articles/srep11573
Terry S. Singeltary Sr.
