Chapter 7 - Voluntary Scrapie Flock Certification Program

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Table of Contents

7.1 The Disease

Note: The use of the term "scrapie" refers to classical scrapie only; certification does not cover "atypical" scrapie, which is clinically, pathologically, biochemically and epidemiologically unrelated to classical scrapie.

Etiology

  • 1. Scrapie, a fatal disease, affects the central nervous system of sheep and goats and belongs to the family of diseases known as the transmissible spongiform encephalopathies (TSEs). While the precise cause of these diseases is still a subject of significant research, abnormal prion protein is associated with the presence of disease. This abnormal prion protein converts normal host prion proteins into the abnormal form. The accumulation of this abnormal prion protein is believed to cause the clinical signs of the disease.

Susceptible Species

  • 2. Scrapie is a naturally occurring disease of domestic and wild (mouflon) sheep and goats.

Distribution

  • 3. The disease was first reported in sheep over 250 years ago, and in Canada in 1938. Scrapie has been diagnosed in both sheep and goats in Canada, with the majority of cases identified in Ontario and Quebec. Scrapie is currently recognized in many small ruminant-raising countries all over the world. New Zealand and Australia are notable as countries recognized free from the disease.

Epidemiology

  • 4. The primary method of infection for most animals is through exposure to scrapie-infected sheep or goats and their scrapie-contaminated environment. It is thought that scrapie is most commonly spread from infected females to lambs or kids at birth through contact with the placenta and placental fluids, which contain large quantities of infectious scrapie prions. Healthy animals become infected by eating or licking contaminated materials in the lambing or kidding environment. Newborn lambs and kids sharing the same contaminated environment (lambing pen) are extremely susceptible to infection. Adult animals sharing the same environment are also at risk.

Transmission of scrapie between animals has been documented in the absence of lambing, and infectious prions have been found in feces, saliva and milk from both clinically and sub-clinically infected animals. As a result, pasture previously grazed by infected small ruminants or buildings previously inhabited by them may represent a transmission risk. Further, animals incubating the disease and even animals that never develop clinical signs may be a source of infection to others.

Abnormal prion proteins are extremely resilient with regards to traditional approaches to disinfection, as they are very resistant to both chemical and physical inactivation and stable over a wide pH and temperature range. While they undergo a significant decrease in infectivity titre with time, they have been demonstrated to persist in the environment for years. Reports indicate that environmental contamination as much as 16 years earlier can result in the reintroduction of scrapie infection.

There is no evidence to date that implicates semen in the transmission of scrapie. Several separate research studies on the potential of scrapie transmission by embryos have produced conflicting results. The research in this area has been assessed and the World Organisation for Animal Health (OIE) Terrestrial Animal Health Code currently states that when authorizing import or transit of in-vivo sheep-derived embryos, no scrapie-related conditions should be required, regardless of the scrapie risk status of the sheep and goat populations of the exporting country, zone or compartment. This applies as long as the embryos are handled in accordance with OIE embryo collection and processing requirements.

Genetic Effects

  • 5. Genetic makeup has been determined to be a significant factor in a sheep's susceptibility to infection with scrapie. At the present time, studies on goat genetics and scrapie susceptibility are more limited and less clear.

Current evidence indicates that there are different forms of the sheep prion protein. Some forms are highly susceptible to the structural transformation to the abnormal form found in scrapie, while others are resistant to this change. As in all mammals, sheep are diploid organisms, so that all cells contain two copies of each chromosome and, thus, two copies of the gene that codes for the normal prion protein. Genes are made up of codons. A codon is a stretch of DNA that determines which particular amino acid will be included at a particular location of a protein (in this case, the prion protein). The prion protein is composed of 256 amino acids; therefore, there are 256 codons determining these amino acids. In the literature concerning susceptibility to various strains of scrapie, three codons are discussed: 171, 154 and 136. In North America, two of these codons are given primary importance: 171 and 136. The presence of an arginine (R) at codon 171 of the prion protein confers resistance to the infectious scrapie prion protein. The presence of glutamine (Q) or histidine (H) – treated the same as a Q at codon 171 – is associated with susceptibility to the infectious scrapie prion protein. An alanine (A) at codon 136 confers resistance to the scrapie prion protein, while the presence of valine (V) at codon 136 confers greater susceptibility. V at site 136 is linked with Q at site 171, such that R cannot be found at site 171 in combination with V at site 136.

Scrapie susceptibility as defined by the codons 171 and 136 is as follows:
Sheep's Genotype (136, 171) Susceptibility to classical scrapie
AA RR Negligible
AA QR Very low
AV QR Intermediate
AA QQ
AV QQ
VV QQ
High

It is still not definitively known whether animals with less susceptible genotypes do not become infected with the scrapie agent or whether they are merely protected from developing the clinical signs of scrapie.

The vast majority of positive cases of scrapie that have been genotyped in North America have been determined to be homozygotes for QQ at codon 171. Small numbers of QRs around the world have tested positive for scrapie. In these cases, the amino acids at codon 136 are examined and heterozygotes for A and V at codon 136 appear to indicate greater susceptibility among the QR population. Although no cases of scrapie with 171RR genotype have been reported in North America, a couple of cases have been reported in Europe.

Recent science indicates that the genotype of the fetus influences the migration and accumulation of abnormal prion in the placenta of an infected ewe. The placenta of a 171QQ infected ewe carrying a 171QQ fetus accumulates large quantities of abnormal prion, which is then shed during birth or abortion. However, the abnormal prion does not accumulate in the placenta of a fetus with a 171QR or 171RR genotype. This means that use of a 171RR ram can prevent the shedding of abnormal prion at lambing, even from infected ewes.

It is important for producers to understand that scrapie genotyping is not disease testing. A 171QQ sheep does not automatically have scrapie, just as there is no absolute guarantee that a 171RR sheep cannot get scrapie. The CFIA does not intend to mandate the Canadian sheep flock to breed for scrapie resistance; rather, scrapie genotyping is a tool that can be used in an overall plan to manage the risk of scrapie on a particular premises. Whether or not a particular producer can or should use scrapie genotyping is a decision to be made based on individual factors such as breed, the prevalence of 171RR within the flock, the management of the ewe flock and the current status of other breeding indices.

Clinical Signs

  • 6. Clinical signs of scrapie rarely develop before the age of 18 months and are highly variable. The majority of cases are diagnosed in animals two to five years of age. As many animals do not show overt clinical signs until late in the course of the disease, significant transmission of the scrapie agent occurs prior to any visible indications of a disease problem. Clinical signs vary considerably, with wasting and debility with or without tremors and a lack of coordination being more prominent features throughout the clinical course of cases of scrapie in Canada. Animals can also just have a poor coat or be found dead.

    The predominant nervous signs of scrapie are as follows:

    • tremors and a lack of coordination;
    • a change in mental status (apprehension, teeth grinding and aggression); and
    • altered sensation (pruritus or itchiness, loss of wool, excoriation and inflammation of the skin, nibble reflex and excessive licking).

Differential Diagnosis

  • 7. Differential diagnosis to consider in the initial clinical stages of scrapie includes the following:
    • ectoparasites (lice, mites);
    • hypomagnesaemia;
    • pregnancy toxemia (ovine ketosis);
    • rabies;
    • listeriosis;
    • maedi-visna;
    • pseudorabies (Aujeszky's disease);
    • sarcocystosis.

Laboratory Diagnosis

  • 8. Scrapie is diagnosed through the detection of the abnormal prion protein in brain or lymphoid tissue. Tissues to submit for post-mortem diagnosis include the obex of the brain and the retro-pharyngeal lymph nodes. Abnormal prion protein has been detected in young animals, but is only consistently detected in animals over 12 months of age. Typically, a preliminary test is administered (enzyme-linked immunosorbent assay [ELISA]), and if this identifies the potential presence of scrapie, it is followed by confirmatory testing using immunohistochemistry and/or Western blot.

Detection of abnormal prions by live animal testing with either third eyelid biopsy or recto-anal mucosa-associated lymphoid tissue (RAMALT) biopsy has highspecificity; however, it has lower sensitivity with false negatives occurring. To maximize sensitivity, third eyelid testing should be applied to ewes over 14months of age with the genotype 171QQ. Similarly, RAMALT testing should be applied to ewes over 12 months of age with the genotype 171QQ, and does over 12 months of age. Lymphoid tissue testingis a useful screening tool for the presence of infection in a flock, but it is not a reliable indicator of individual freedom from disease.

Scrapie genotyping is not testing for disease; it is a screening test that indicates a sheep's relative susceptibility for scrapie. When one is trying to find infection, sheep with the highest susceptibility are the subpopulation in which one is most likely to discover the disease.

Immunity

  • 9. No immune response to scrapie prion protein has been detected.

Public Health

  • 10. Scrapie is not considered to pose a risk to human health.

7.2 Policy and Principles of Control

Policy Statement

The Voluntary Scrapie Flock Certification Program (VSFCP) is a voluntary Canadian program that small ruminant producers can choose to join. Any owner of sheep or goat premises who agrees to comply with the VSFCP may enroll; however, once they are participating in the Program, their compliance with the National Standards is mandatory. The objective of the VSFCP is to provide owners with the opportunity to have their flocks/herds identified as negligible risk with respect to scrapie. The Program certifies flocks/herds with respect to classical scrapie only, and does not cover atypical scrapie, which is clinically, pathologically, biochemically and epidemiologically unrelated to classical scrapie.

The Program is designed to give producers a means of detecting and controlling scrapie within their flock/herd, resulting in recognition that the risk of their animals being infected with scrapie diminishes to negligible with progressive participation in the Program. Being a participating flock/herd and reaching certified status in the Program provides assurances to potential purchasers that the animal for sale is coming from a negligible-risk flock/herd. Recognition of this status can provide market access opportunities domestically and internationally. This Program also provides a valuable vehicle for surveillance for scrapie within Canada, contributing to the National Scrapie Eradication Program.

Statutory Authority

Scrapie is a reportable disease under the Reportable Diseases Regulations, prescribed in accordance with Section 2 of the Health of Animals Act. Any person suspecting an animal of demonstrating signs consistent with scrapie must report that animal to a federal veterinarian at a CFIA district office.

The primary role of the federal government in the VSFCP is to establish the National Standards and to audit for compliance with these standards.

Export Certification

Animals from flocks/herds enrolled in the VSFCP may be certified and endorsed by the CFIA as participating in a program that meets the minimum national standards. The CFIA will work to gain international recognition of the minimum national standards. Certificates documenting participation and level in the VSFCP are obtained from the regional administrator, Canadian Sheep Federation (CSF).

Principles for Control and Eradication

While there are no tests to definitively rule out scrapie in the individual live animal, there are a number of tools that can be used to evaluate the risk of scrapie being present in a sheep flock or goat herd. Ways used to determine the VSFCP status on a flock/herd basis include post-mortem testing, RAMALT testing, genotyping, absence of clinical signs and prevention of exposure to scrapie over a designated period of time.

There are three different approaches or pathways to follow to achieve certification status. The first pathway for sheep or goats relies on surveillance of mature animals that die, the absence of clinical signs, and preventing the exposure to scrapie. A second pathway screens the sheep flock for the presence of scrapie by taking lymphoid tissue samples from either the recto-anal mucosa or third eyelid mucosa from genetically susceptible sheep; and for goat herds, by taking lymphoid tissue samples from the recto-anal mucosa of goats. Once these lymphoid samples test negative for scrapie, the flock or herd does surveillance of mature animals that die and prevents exposure to scrapie. The third pathway to certification is for sheep only, and requires genotyping animals for scrapie resistance as well as ongoing surveillance of mature animals that die.

A scrapie suspect is any animal that has scrapie as a differential diagnosis.

The CFIA implements disease investigation procedures as soon as a clinical suspect is reported.

A scrapie-positive animal is any animal for which scrapie-positive results were reported by the CFIA's National and OIE Reference Laboratory for Scrapie, using at least two CFIA-approved scrapie tests (e.g. ELISA, immunohistochemistry, Western blot) applied to the brain and/or lymphoid tissue.

Any confirmed cases of scrapie results in immediate suspension from the VSFCP. The CFIA implements strict disease eradication measures to eliminate the infection from the premises where it was detected, to determine the source of infection and to identify any spread of the infection from the premises that may have occurred and eliminate it.

7.3 Accredited Veterinarian's Responsibilities

Preliminary Activities

  • 1. Obtain and read the VSFCP chapter in the Accredited Veterinarian's Manual, including the VSFCP National Standards. The Canadian Sheep Federation (CSF) is the VSFCP administrator and status assessor. The VSFCP National Standards and other information for accredited veterinarians are also available on the CSF's Scrapie Canada website.
  • 2. Schedule a meeting with the local CFIA district veterinarian to review the accredited veterinarian's duties for the VSFCP and the procedures that must be followed. A tutorial or a review of the scrapie sampling techniques in small ruminants is suggested at this time.
  • 3. Establish a valid accreditation agreement (contract) with the CFIA district office for the delivery of the VSFCP.
  • 4. Advise the producer to contact the VSFCP regional administrator at the CSF to learn the requirements to participate in, advance and maintain certification within each of the three pathways to certification. The step of applying for entry into the VSFCP is delayed in pathways two and three until additional conditions are met. VSFCP applications are available on the Scrapie Canada website and enrollment procedures are detailed in Section 2 of the VSFCP National Standards.
  • 5. The accredited veterinarian and owner should discuss which of the three pathways to certification they intend to pursue. (VSFCP pathways are described in paragraphs 13 – 27 below). Assessment of the facilities, flock/herd management and record keeping on the premises should be done to gauge the degree to which the accredited veterinarian feels the producer can be successful, and to identify any changes in record keeping or management that would be necessary in order to facilitate the fulfilment of VSFCP requirements.

General Responsibilities

  • 6. The VSFCP is carried out in co-operation with producers, accredited veterinarians, national stakeholder organizations, approved laboratories and the CFIA. Roles and responsibilities for each of these partners are listed in the VSFCP National Standards.
    • Accredited veterinarian general responsibilities are listed in Section 1.4 Program Delivery of the Standards.
    • Owner responsibilities include those listed in Section 1.6 Producers and Section 3. General Rules of the Standards. It is also the owner's responsibility to comply with all requirements of the selected pathway.

Annual Physical Inspection, Inventory and Report

  • 7. General rules for the three certification pathways are in Section 3 of the VSFCP National Standards. Each pathway also has individual requirements listed in the Standards.
  • 8. The accredited veterinarian must visit the enrolled premises at least once a year. The annual physical flock/herd inventories must be conducted as per Section 3.10 Flock/Herd Inventories of the VSFCP National Standards under the supervision of the accredited veterinarian. Appropriately trained third-party personnel, such as animal health technicians or veterinary students, may participate. The inventory will identify every sheep and goat on the premises, and the accredited veterinarian must assess for any clinical symptoms of scrapie.
  • 9. The annual inventory report is the responsibility of the accredited veterinarian. The foundation of the annual inventory report is the reconciliation of this year's annual inventory with the previous year's annual inventory. The annual report requirements are listed in Section 3.11 Annual Report of the VSFCP National Standards.
  • 10. When the accredited veterinarian is satisfied that the report adequately documents all reconciliation of the inventory, the report is signed. The document is forwarded to the VSFCP administrator and status assessor within the anniversary quarter (January 1 – March 31; April 1 – June 30; July 1 – September 30; October 1 – December 31) in which the enrolled flock/herd was registered in the Program. Along with the report, the owner submits an application to advance to the next level of the Certification Program or to maintain certified status once the level has been attained.

Deadstock Testing

  • 11. Deadstock testing is the most critical element of the Program, and the absence of even one submission without documented cause will jeopardize the status of the flock/herd within the Program. Detailed requirements for deadstock testing are listed in both the general rules and in the specific pathway requirements of the VSFCP National Standards. The nearest approved laboratory for scrapie testing should be identified by both the accredited veterinarian and the producer. The accredited veterinarian or the producer may submit the head or brain sample directly to the laboratory. The accredited veterinarian should review how to sever the head, and indicate that samples should be stored frozen. Heads/samples may be held and sent, or delivered in batches. See Section 7.5 Appendix A for brain sampling procedures.

Sick Animals

  • 12. Owners are instructed in the VSFCP National Standards to report illness in a sheep or goat over 12 months of age lasting longer than two weeks, with the exception of a physical injury. The accredited veterinarian will be responsible for monitoring the outcome of the case and for reporting the case to the CFIA if scrapie is a differential diagnosis. The accredited veterinarian should educate the owner to recognize the clinical signs of scrapie and provide information on the epidemiology of the disease.

Voluntary Scrapie Flock Certification Program Pathways

Pathway 1: Limited Acquisitions Plus Surveillance

  • 13. This pathway is available to goats and sheep.
  • 14. The accredited veterinarian should advise the producer that at the current time, pathway 1 is the only pathway of the Canadian VSFCP designed using OIE's scrapie chapter guidelines for a scrapie-free establishment. Pathway 1 involves limiting acquisitions to animals from similar or higher status flocks/herds and ongoing surveillance through submission of deadstock for scrapie testing.
  • 15. All requirements detailed in the VSFCP National Standards are applicable to flocks/herds participating in this pathway. The Standards are included in this module of the Accredited Veterinarian's Manual (AVM) and are also available on Scrapie Canada's website under the VSFCP Rules and Regulations. In the Standards, Section 3. General Rules and Section 4. Program Specific Pathway 1 details the general and specific rules for this pathway.
  • 16. The Program pathway includes six levels, from the entry level (level E) to the highest level (certified). A minimum of five years (one year each at levels E, D, C, B and A) is necessary for a registered flock to reach the certified level. Once a flock has reached the certified level, it maintains this level provided that the applicable requirements continue to be met. The OIE's scrapie chapter guidelines require seven years of compliance to qualify as a scrapie-free establishment.

Pathway Two (A and B): Live Animal Screening plus Surveillance

Pathway 2A – Third Eyelid Biopsy
Pathway 2B – RAMALT Biopsy
  • 17. Pathway 2A is only available to sheep; it is not available to goats. Pathway 2B is available to both sheep and goats.
  • 18. The accredited veterinarian should advise the producer that, at the current time, these pathways, while based on internationally recognized science, are not consistent with OIE's scrapie chapter guidelines for a scrapie-free establishment. Pathway 2 involves screening all susceptible animals by means of the third eyelid test (sheep only) or the recto-anal mucosa-associated lymphoid tissue (RAMALT) biopsy test. Negative results give a reasonable level of assurance that disease is not present in the flock/herd and results in obtaining advanced status. Like pathway 1, pathway 2 also involves limiting acquisitions to animals from similar or higher status flocks/herds and ongoing surveillance through submission of deadstock for scrapie testing.
  • 19. All requirements detailed in the VSFCP National Standards are applicable to flocks/herds participating in this pathway. The Standards are included in this AVM module and are also available on Scrapie Canada's website under VSFCP Rules and Regulations. In the Standards, Section 3. General Rules and Section 5. Program Specific Pathway 2A and Program Specific Pathway 2B detail the general and specific rules for this pathway.
  • 20. The Program pathway includes three levels, starting at level B to the highest level (certified). A minimum of two years (one year each at levels B and A) is necessary for a registered flock to reach the certified level. Once a flock has reached the certified level, it maintains this level provided that the applicable requirements continue to be met.
  • 21. A veterinarian accredited to deliver the VSFCP must collect the appropriate samples for the live animal screening. See Section 7.5 Appendices C and D for sampling procedures.

Pathway Three: Genetic Selection

  • 22. This pathway is only available to sheep; it is not available to goats. Entry into this pathway can be accomplished in two ways: whole flock screening or rams-only screening.
  • 23. The accredited veterinarian should advise the producer that, at the current time, this pathway, while based on internationally recognized science, is not consistent with OIE guidelines for a scrapie-free establishment. Pathway 3 is based on genetic selection for scrapie resistance, utilizing genotyping, and eliminating all susceptible animals from the breeding flock. Ongoing surveillance through submission of deadstock continues to monitor for the presence of disease.
  • 24. All requirements detailed in the VSFCP National Standards are applicable to flocks/herds participating in this pathway. The Standards are available in this AVM module and are also available on Scrapie Canada's website under VSFCP Rules and Regulations. In the Standards, Section 3. General Rules (parts 3.20 – 3.21 discuss genotyping), Section 6. Whole-Flock Genetic Screening and Section 7. Rams-Only Genetic Screening details the general and specific rules for this pathway.
  • 25. There are two distinct ways in which producers may prepare their flocks for application into this pathway. The accredited veterinarian is advised to assist the producer in the decision whether or not to use pathway 3 and, if so, whether to use whole-flock genetic screening (Section 6 of the Standards) or rams-only genetic screening (Section 7 of the Standards) for application into this pathway. The rams-only genetic screening method genotypes rams and uses 171RR rams exclusively. The whole-flock genetic screening method genotypes all breeding stock, and uses the 136AA 171QR and171RR rams and ewes. This may be an iterative process of testing and decision making. The producer may undertake to test only breeding rams at first. With these results, it may be possible to determine whether there is a sufficient base of genetic resistance to scrapie to start a breeding program for scrapie resistance without substantial loss of other production traits, using only 171RR rams. If there is an insufficient base of genetic resistance in the ram population, the producer may undertake to test the rest of the breeding flock. These results may then be reviewed to determine whether there is a sufficient base of genetic resistance across the ewes and rams to breed for resistance to scrapie without substantial loss of other production traits.
  • 26. The Program pathway includes two levels, starting at level A, once all breeding sheep are documented to be 136AA 171QR or 171RR, to the highest level (certified). After 12 months at level A, the producer may apply to advance to the certified level. Once a flock has reached the certified level, it maintains this level provided that the applicable requirements continue to be met.
  • 27. A veterinarian accredited to deliver the VSFCP must supervise the collection of appropriate samples for genetic testing. See Section 7.5 Appendix B for sampling procedures and Appendix G for a list of CFIA-approved laboratories for genotyping.

7.4 National Standards for the Voluntary Scrapie Flock Certification Program

Introduction

Participation in the Voluntary Scrapie Flock Certification Program (VSFCP) is optional. The program is designed to give producers a means of detecting and controlling scrapie within their flock/herd, resulting in recognition that the risk of their animals being infected with scrapie diminishes to negligible with progressive participation in the program. A sheep or goat producer can join the VSFCP provided that the producer agrees to adhere to the program rules. The program certifies flocks/herds with respect to classical scrapie only, and does not cover "atypical" scrapie which is clinically, pathologically, biochemically and epidemiologically unrelated to classical scrapie. Atypical scrapie may, in fact, be a non-contagious, spontaneous degenerative condition of older sheep. As such, throughout this document, when the term "scrapie" is used, it refers to classical scrapie only.

Since there is no test to to rule-out the disease in the individual live animal, "scrapie-negligible-risk" status is based on the results of surveillance testing carried out on deadstock, screening the flock/herd for presence of disease, removing genetically susceptible animals, restricting animals entering the flock/herd, and the absence of clinical signs.

There are three separate paths that can be followed for a flock/herd to achieve certified status. Pathway 1 involves limiting acquisitions to animals from similar or higher status flocks/herds and ongoing surveillance through the submission of deadstock for scrapie testing. The program includes six levels, from the entry level (level E) to the highest level (certified). A minimum of five years (one year each at level E, D, C, B, A) is necessary to reach the certified level on the program. Pathway 1 is the only pathway of the 3 available pathways that is consistent with OIE guidelines. To qualify as a scrapie-free establishment OIE guidelines must be complied with for at least 7 years. This is not to be confused with Canada's definition of negligible risk. Flocks /herds on the VSFCP are considered to have negligible risk for classical scrapie after reaching Certified Level which may be reached after 5 years on the program.

Pathway 2 involves genotype screening sheep to identify adults that possess the genotype susceptible to scrapie (goats are not genotyped), and then screening the animals by means of the third eyelid test or recto-anal mucosa associated lymphoid tissue (RAMALT) biopsy test. Negative results give a reasonable level of assurance that the disease is not present in the flock/herd and the flock/herd may apply to enter at level B. Ongoing surveillance of deadstock continues to monitor for the presence of the disease.

Pathway 3 involves genotype screening and elimination of genetically susceptible sheep from the breeding flock. The flock may then apply to enter at level A. Ongoing suveillance of deadstock continues to monitor for the presence of the disease.

The VSFCP is carried out in co-operation with producers, accredited veterinarians, national stakeholder organizations, provincial governments, approved laboratories and the Canadian Food Inspection Agency (CFIA). The roles assumed by each of these organizations may vary in different regions of Canada.

1. Roles and Responsibilities

1.1 National Standards Development and Audit

This role and the associated responsibilities will be assumed by the CFIA in all situations. The CFIA is responsible for the development, using a consultative process, of national (minimum) standards for a scrapie flock certification program. Modifications and updates to these standards will be undertaken as required. The CFIA is responsible for providing the current national standards to the organizations responsible for regional administration (see point 1.2 below).

Where the regional administration is assumed by organizations other than CFIA, it is the CFIA's responsibility to review any scrapie flock certification program proposed for the specific region of Canada and determine equivalency to the published national voluntary scrapie flock certification program standards. International negotiation for recognition of the program and endorsement of export certification by the CFIA will only be done for those scrapie flock certification programs judged by the CFIA to meet the national standards.

The CFIA is responsible for conducting audits of program design and implementation to verify that the scrapie flock certification program in a particular region of Canada meets the national standards.

The CFIA is responsible for the design and implementation of a quality assurance program for non-CFIA laboratories performing transmissible spongiform encephalopathy (TSE) testing, and laboratories providing genotyping for scrapie susceptibility. All confirmatory testing on suspect or positive scrapie tissue samples will be performed by a CFIA laboratory. In the case of a confirmed positive animal, the CFIA will implement an official disease control program. Discrepancies between genotyping results from two laboratories will be subject to final genotype testing by a CFIA laboratory.

The CFIA is responsible for ensuring a publicly accessible report (e.g. published on the website) of all enrolled flocks and herds and their status is maintained. This report will be updated on a quarterly basis.

1.2 Regional Administrator

This role and the associated responsibilities may be assumed by a national or provincial industry group, the provincial government or the CFIA Program Network. The regional administrator is responsible for overseeing enrolment and membership in the scrapie flock certification program for a particular region of Canada, including the following:

  • developing a program that meets the national standard;
  • developing and distributing a contract (application form) for entry into the program;
  • developing and distributing forms required for the program, including application forms, annual reports, inventory reports and flock/herd status certificates;
  • collecting and collating all data on enrolled flocks or herds in that region;
  • issuing certificates indicating the status of a flock/herd;
  • issuing a certificate indicating that a sheep is a member of a herd enrolled in the certification program and indicating the status of the flock/herd;
  • informing the CFIA VSFCP coordinator of the status of all enrolled flocks/herds on a quarterly basis; and
  • designing an appeal process for decisions made with respect to the voluntary flock certification program, e.g. regarding compliance with national standards.

1.3 Status Assessment or Status Assessor

The role of assessor of flock/herd status may be assumed by a national or provincial industry group, the provincial government or the CFIA district office. The status assessor is responsible for the following:

  • receiving and reviewing completed applications for enrolment into the VSFCP;
  • accepting a flock or herd into the appropriate level of the program or informing the producer or the responsible veterinarian of any outstanding requirements that prevent enrolment at that time;
  • verifying that initial and annual flock/herd inventories and additional records for all additions and deletions are complete;
  • suspending VSFCP status in the event of reported irregularities;
  • investigating flock/herds that are suspended and proceeding with reinstatement or revocation of VSFCP status;
  • updating the regional administrator of the VSFCP of changes in the status of a flock or herd (additions, suspensions, revocations) as they occur; and
  • implementing the appeal process to determine whether an exemption should be granted for enrolled owners who failed to comply with national standard program requirements.

1.4 Program Delivery

Program delivery is carried out by a veterinarian accredited by the CFIA. A CFIA veterinarian or a veterinarian who is an employee of a provincial department that is the status assessor or regional administrator may also carry out program delivery, and can be substituted anywhere the services of an accredited veterinarian is required in the standards. The inventory portion of the initial or annual report may be conducted by an accredited veterinarian, an animal health technician supervised by the accredited veterinarian, a CFIA veterinarian, or staff of a provincial department or agency that is the status assessor or regional administrator.

Veterinary practitioners are authorized (accredited) by the CFIA or the appropriate provincial government to perform inspections, to take samples for diagnostic or genotyping purposes and to check records.

To obtain accreditation, a veterinarian must successfully complete the training indicated in the Accredited Veterinarian's Manual or its provincial equivalent.

The accredited veterinarian must sign the application form completed by the owner.

If the owner decides to stop doing business with the accredited veterinarian who signed the original application form, the new accredited veterinarian must be asked to sign a copy of the form, or - if the situation has changed - a new application form.

In rare instances where a flock or herd has been subject to CFIA disease control actions as a result of being declared positive for scrapie, a CFIA veterinarian may act as the program delivery person for the VSFCP during the mandatory follow-up period for deadstock surveillance, for a period of five years, regardless of pathway joined.

Program delivery personnel are responsible for the following:

  • reviewing the requirements of the program and responding to questions from the owner of the premises applying for or enrolled in the program;
  • teaching the owner to recognize the clinical signs of scrapie, and providing information on the epidemiology of the disease and flock/herd management;
  • conducting or supervising a flock/herd inventory including verifying requirements are met for any males with an individual status level;
  • assessing the health of the flock/herd to determine whether any sheep or goat is demonstrating signs of scrapie;
  • immediately notifying the CFIA of the existence of any animal suspected of having clinical scrapie;
  • reconciling records to ensure that the program requirements are met;
  • signing reports, including the annual inventory, and submitting them to the status assessor;
  • collecting or supervising the collection of samples, and submitting them for genotyping;
  • collecting and submitting tissue samples from deadstock if there is a request from the owner to do so;
  • identifying structures on a premises that may have been used to feed, water, contain or birth small ruminants (if necessary);
  • being familiar with prionicidal agents and the correct concentration to which they must be made; and
  • supervising and approving appropriate cleaning and disinfection of a premises (if necessary).

1.5 Laboratories

Laboratory approval is accompanied by training and implementation of a quality assurance program established by the CFIA. A member of the laboratory staff must have taken CFIA training in order to be able to supervise scrapie tests and ensure that the quality assurance program is followed. Laboratories providing diagnostic testing services for the VSFCP are responsible for the following:

  • collecting, preparing and testing tissue samples in accordance with the CFIA national protocol for the diagnosis of scrapie or genotyping blood samples for codon 136 and 171 of the scrapie incubation gene;
  • participating in the quality assurance program designed by the CFIA Laboratories Directorate;
  • forwarding suspect samples to the appropriate CFIA laboratory (Ottawa – Fallowfield) for confirmation (the results not being reportable to the owner or the accredited veterinarian);
  • providing required forms;
  • providing appropriate shipping containers;
  • notifying the owner, the accredited veterinarian responsible for the flock/herd and the status assessor of negative test results;
  • assessing whether a tissue sample is adequate to permit diagnosis of scrapie and notifying the owner, accredited veterinarian and status assessor of samples that are not adequate; and
  • disposing of tissues and carcasses in accordance with the environmental regulations in force in the province and territory. (Positive carcasses must be disposed of by burial or incineration.)

1.6 Producers

In this program, an owner is a person who owns the premises and the animals on the premises. A producer is a person who has responsibility for the care and handling of all animals on a premises; this person may or may not be the owner.

The owner of a flock/herd wishing to enrol in the VSFCP is responsible for the following:

  • identifying animals in the flock/herd;
  • providing the necessary facilities and assistance for inspection and handling of the animals;
  • obtaining the services of a veterinarian accredited by the CFIA or the province to deliver the VSFCP;
  • assisting accredited veterinarian in conducting annual inventories;
  • obtaining, maintaining and compiling all relevant documentation of animal acquisitions and departures (keeping records);
  • depending on the program pathway being followed, submitting the appropriate tissue samples for laboratory analysis with appropriate animal identification;
  • immediately reporting to the CFIA district veterinarian any animal suspected of being clinically affected by scrapie;
  • agreeing, with reasonable notice, to make the animals and records available so that the accredited veterinarian, the provincial regulatory agency and the CFIA can inspect them; and
  • if stocking a new flock/herd on a new premises for purposes of retaining a higher status, determining whether small ruminants have been contained on the premises in the last 10 years.

2. Administration

2.1 Enrolment Procedure

The flock owner contacts the local CFIA district veterinarian to determine the organizations responsible for the VSFCP in the region in which the flock/herd is located.

The owner contacts the VSFCP regional administrator and requests an application package.

The owner may only join one pathway to certification at a time. Specifically, any flock/herd and all the individual animals within the flock/herd can only be registered in one pathway to certification at a time.

An application package is completed and submitted to the organization responsible for status assessment. The applicant must indicate which Program Specific Pathway to Certification will be pursued. The application must be accompanied by the following:

  • a site plan of all buildings and grazing premises to which the animals are given access;
  • the initial flock/herd inventory prepared by the accredited veterinarian within the three-month period immediately prior to submission of the application;Footnote 1 and
  • a record-keeping plan (objective: records must be reviewed completely and effectively at each annual inspection).

Accelerated admission to more advanced levels of the VSFCP may be possible for flocks/herds which have met all program requirements for a number of years prior to application.

A currently enrolled owner wishes to change pathways would be required to start at entry level on the new pathway, or if all program requirements for the new pathway have been met, credit may be given for the number of consecutive years of compliance that were completed prior to application to the new pathway. Entry at an advanced level may therefore be possible.

A flock/herd that has been subject to the CFIA Scrapie Disease Control Program may be admitted to the certification program at the level at which it meets the certification program requirements.

Owners who will be starting a new flock/herd with acquired animals of status D or higher and who intend to keep that status will need to follow all regular application form protocols as above, but in addition, provide a letter (written by the owner) stating that the premises where the flock will reside meets one of the following conditions:

  • the premises has not contained small ruminants for the last 10 years; or
  • it is unknown whether the premises contained small ruminants in the last 10 years; or
  • the premises has contained small ruminants in the last 10 years.

In cases where owners will be starting a new flock/herd with acquired animals of status D or higher and they intend to keep that status on a premises that, within the last 10 years, has previously contained (or it is unknown whether it previously contained) small ruminants, all regular application form protocols as above will need to be followed, and the owner will agree to follow the approved cleaning and disinfection protocol for the VSFCP under the supervision of their accredited veterinarian prior to stocking any animals on the property. To retain the higher status, it will be necessary for the accredited veterinarian to certify to the administrator that the cleaning and disinfection has been done in a satisfactory manner prior to stocking the animals on the premises.

Flock/herd owners successfully enrolling in the VSFCP and quitting the VSFCP within the same 24-month period will not be permitted to re-enrol in the VSFCP for a period of three years from their date of departure from the program (subject to appeal).

In addition, flock/herd owners who obtain temporary enrolment and do not complete the requirements for full enrolment in the VSFCP will not be permitted to re-enrol in the VSFCP for a period of three years from their date of acceptance for temporary enrolment  (subject to appeal).

2.2 Advancement and Downgrading

An owner may apply to have the certification status of the flock/herd upgraded if the following conditions are met:

  • the premises is not currently subject to CFIA actions related to the scrapie program; and
  • the flock/herd has met the minimum requirements applicable to its current certification level.

To upgrade the certification status of the flock/herd, the owner must submit a request along with the annual report that would make them eligible for advancement to the status assessor for review and approval. The request must be completed and signed by the owner and the accredited veterinarian on record.

The status assessor reviews the annual report and approves advancement or identifies deficiencies that prevent advancement.

When deficiencies are identified, the status assessor may require that the current level be maintained until the deficiencies are addressed, or that the status of the flock/herd be downgraded or suspended. The decision is documented to the program participant and copied to the accredited veterinarian and the regional administrator.

Owners successfully participating in the VSFCP (at level E or above) who have purchased one or more females from a non-enrolled or level E flock/herd, resulting in downgrading to status E (or penalty to remain at level E), will not be permitted to introduce additional females from non-enrolled or level E flocks/herds for a period of three years from the date of their previous introduction or downgrading within the program (subject to appeal).

Regardless of the certification pathway that is pursued, once a flock/herd has attained the certified level, annual application for renewal of this level is required. The owner must submit a request to maintain the status of certified, along with the annual report that documents the fact that all ongoing requirements have been met, to the status assessor for review and approval. The request must be completed and signed by the owner and the accredited veterinarian responsible for the flock/herd.

2.3 Suspension/Revoking of Registration/Appeals

If the owner of a registered flock/herd contravenes the program rules, the organization responsible for status assessment will temporarily suspend the certification status of the flock/herd, and after reviewing the situation, may reinstate at the same level, downgrade, or revoke the status of the flock/herd and remove it from the program.

An owner whose flock/herd is under review for possible removal from the program will be given the opportunity to submit any relevant information to the status assessor, provided that this is done no later than 30 days after suspension.

Any owner who fails to submit an inspection report within the month following the end of the anniversary quarter will have their flock/herd automatically suspended.

The status assessor will notify the owner and the accredited veterinarian in writing of the reasons for the decision and give the owner the opportunity to appeal within the following 60 days. The notice will include the name and address of the responsible person within the appeal committee as established by the status assessor.

An owner whose flock/herd has been removed from the program due to contravention of program rules may submit a new application after meeting the conditions stipulated in the program. In such a case, the owner must submit satisfactory proof to the status assessor that steps have been taken to ensure that the flock/herd will meet the program requirements in the future. In the case of a flock/herd that is reinstated in the program, the reinstatement level will depend on the reasons for suspension. The flock/herd will not be automatically reinstated at its previous level. In cases where the flock/herd was removed for reasons of information falsification, failure to report to a veterinary inspector that an animal might have scrapie, or any other action that might expose other animals to scrapie, an owner may lose the privilege of registering in the program.

If a participating flock/herd is found to be either infected with, or a source of scrapie, its certification status will be immediately suspended. The flock/herd will be subject to the scrapie eradication program governed by the Health of Animals Act and the Health of Animals Regulations. Following completion of the scrapie eradication program procedures, the flock/herd may be reinstated in the VSFCP at the appropriate pathway and level.

A producer may appeal a decision regarding advancement or downgrading in the event of an incomplete or unsatisfactory application for advancement. A producer may also appeal a temporary suspension or a revocation of registration, but not both.

2.4 Reports

The results of all reports, including information on registrations, tests, suspensions, revocations, and changes in status, are distributed to the owner, the accredited veterinarian and the CFIA district veterinarian.

The regional administrator will maintain a list of all flocks and herds enrolled in the program, the pathway and their current level on the Scrapie Canada website. Flock/herds for which a report is not submitted to the status assessor within the prescribed time will be identified on the website as being suspended.

The quarterly report published by the CFIA will be produced and automatically distributed to all provinces, and/or published on the website. It will list all registered and certified flocks and herds, along with their pathway and certification levels.

Records must be kept of feed given to animals, according to the Health of Animals Act and the Health of Animals Regulations.

2.5 Review of the Program

The VSFCP will be reviewed on an annual basis and/or as the scientific information becomes available and changes are required.

3. General Rules

These requirements must be met by participants in all three certification pathways.

3.1

The certification program must be open to any owner of a premises on which sheep or goats are kept, provided that the owner and the premises meet the program requirements and the owner of the premises has not had the right to participate in the VSFCP removed (revoked).

3.2

All sheep and goats on a premises must be included in the flock/herd enrolled in the certification program, ownership notwithstanding.

3.3

Multiple premises must be listed under the same certification contract if the premises belong to the same owner and are located  contiguous to each other.

Multiple premises that are non-contiguous to each other still need to be included under the same certification contract if the small ruminants on the premises meet the definition of established herd.

Multiple non-contiguous premises may be permitted to be enrolled under different certification contracts (i.e. different flocks/herds with separate statuses) if they are not considered an established herd (see definition), including no exchange of animals, and no direct or indirect (shared use of pasture, facilities, equipment) contact of animals.

3.4

The flock/herd owner must arrange for the services of an accredited veterinarian (or equivalent) to deliver the VSFCP. The accredited veterinarian's acceptance of their role in implementation of the VSFCP within the identified flock/herd is reflected by their signature on the application form.

3.5

The owner of a flock/herd must report to their accredited veterinarian any illness in a sheep or goat over 12 months of age lasting longer than two weeks, except a physical injury. The accredited veterinarian will be responsible for monitoring the outcome of the case and for reporting the case to the CFIA if scrapie is a differential diagnosis. If CFIA determines the animal may be a scrapie suspect, then CFIA's scrapie eradication program procedures must be followed. If the flock/herd is found to be infected with scrapie or a source of scrapie, its certification status will be immediately suspended. The flock/herd will be subject to the CFIA's scrapie eradication program governed by the Health of Animals Act and the Health of Animals Regulations.

3.6

All animals aged 12 months or more must be identified with two unique identification devices.

3.7

Animals less than 12 months of age must be identified in a manner that enables the owner to track these animals in the flock/herd inventory. All animals aged less than 12 months must be appropriately identified (as required by regulation) when a change in ownership occurs or when the animals are moved outside their usual location (e.g. exhibition, insemination centre, sales barn or auction barn).

3.8

The owner must keep detailed flock/herd records of every sheep or goat that is born on or enters the premises, no matter who the owner is or who is responsible for the sheep or goat. The records must be kept for a period of five years after the animal has left the flock/herd or has died. They must be made available to the program delivery person or the CFIA inspector at any reasonable time and must be presented at the time of each annual inventory.

For all animals in the flock/herd, the basic minimum data that must be maintained in records and submitted as part of annual reports includes the following:

  • the animal's identifiers;
  • the date the animal entered the flock/herd (day if available, month and year);
  • the animal's sex;
  • the source of the animal (homegrown, purchased, loan);
  • if the animal was not born in the flock/herd, the name and address of the person from whom it was obtained along with:
    • the flock/herd status certificate issued for the flock/herd of origin of female animals;
    • The flock/herd status certificate issued for the flock/herd of origin of male animals or documentation for rams of genotype 136AA 171RR or 136AA or 171QR as required in 4.11 pathway 1;
    • a list of males being maintained separate from the flock/herd, their individual status level and documentation as required in 4.11 pathway 1;
  • the date the animal left the flock/herd;
  • the reason for the animal leaving and appropriate documentation (a shipping invoice if shipped, a receipt if sold, death record);
  • the records for slaughter lambs and kids (under 12 months) may be reported in groups;
  • scrapie testing results for deadstock over 12 months of age: and
  • scrapie testing results for any live animal testing required if using the alternative sampling protocol detailed in pathway 1.

Additional information that is required for pathway 3 is as follows:

  • identifiers of the sire and dam; and
  • genotype testing results as required for pathway 3.

3.9

Sheep or goat milk, colostrum or their derived products destined for use in sheep or goats may only be sourced from sheep or goats in the same flock/herd or from a flock/herd on the VSFCP of greater or equal status as the recipient flock. Sheep or goat milk, colostrum or their derived products from a lower status flock/herd or a flock/herd not enrolled in the program will result in downgrading in status of the recipient flock /herd. Sheep and goat milk and colostrum or their derived products from a scrapie – positive animal, a scrapie suspect animal or a genetically susceptible exposed animal (136AA 171QQ, 136AV 171QQ, 136VV 171QQ, 136AV 171QR) may not be used. Bovine milk and colostrum and their derived products may be used. Appropriate biosecurity standards should be applied when sourcing milk and colostrum from any source including bovine.

Flock/Herd Inventories

3.10

Inventories (initial and annual) will be conducted by the accredited veterinarian or an appropriate third party supervised by the accredited veterinarian. The inventory will identify all sheep and goats on the premises. During the inventory inspection, all animals over 12 months of age in the flock/herd must be identified individually (by tag) and the veterinarian must check for any clinical symptoms of scrapie. For extremely large flocks/herds using electronic inventories, all animals over 12 months of age must be identified individually and their identifiers must be physically verified over the course of the year. However, only a statistically significant random sampling must have their identifiers physically verified during the annual inventory inspection. Sampling tables are available upon request. If a flock/herd inspection is performed by a CFIA veterinary inspector for the purposes of the scrapie disease control program, this may replace part or all of the annual inspection by the accredited veterinarian.

Annual Reports

3.11

The annual report lists the following:

  • all identification of each sheep and goat on the premises at the time of the inventory;
  • all identification devices placed on each sheep or goat, including the current lamb or kid crop and any sheep or goats that have lost identification devices;
  • all sheep or goats that have entered or left the premises since the last inventory;
  • slaughter lambs and kids (under 12 months) movement may be reported in groups;
  • the status of the flock/herd of origin for those sheep or goats entering the premises;
  • the genotypes for each ram entering the premises where genotyping is required;
  • all males maintained separately from the flock/herd and their individual status level;
  • all deaths;
  • the destination of every sheep or goat that moved off the premises as established by a bill of sale or, if the animal has not been sold, a signed document showing the destination of the sheep or goat;Footnote 2
  • appropriate laboratory results (genotyping or scrapie testing); and
  • a letter signed by the producer documenting that the sourcing of sheep and goat milk, colostrum and their derived products destined for use in sheep or goats since the last application for advancement, has been sourced from within the flock/herd or from flocks/herds of equal or higher status on the VSFCP.

The report must be forwarded to the status assessor within the anniversary quarter in which the certified flock/herd was registered. The status category is effective from the date when the flock/herd is accepted within the program, and the anniversary quarter for subsequent years is the quarter in which the acceptance date falls (Jan. 1-March 31; April 1-June 30; July 1-Sept. 30; Oct. 1-Dec. 31).

In all cases, the owner is ultimately responsible for clarifying any inventory questions/concerns that may arise during the course of the review of the annual report by the status assessor.

Deadstock Testing

3.12

If no suitable deadstock samples have been submitted for testing for a period of time equal to or exceeding 12 months, at least one animal 18 months of age or older, which has resided in the flock/herd for no less than 18 months, is to be humanely destroyed (in any manner: slaughter, euthanasia) and a sample submitted for testing. If humanely destroying an animal for deadstock testing will have a significant impact on the flock or herd due to its small size, a producer enrolled on pathway 1 may be able to advance using the alternative live animal sampling protocol detailed in 4.5.

Alternatively if no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, an enrolled producer may be permitted to remain on the program without advancing to the next level for one additional year (allowing time to raise an animal for slaughter and testing). For certified producers, they would incur a one year status penalty dropping them from certified to Level A.

3.13

The head of the animal may be submitted directly to an approved provincial laboratory by the producer, or the accredited veterinarian may collect brain samples for submission to either an approved provincial laboratory or to a CFIA district office to be sent to a CFIA laboratory (as part of the national scrapie surveillance program). The brain samples may be collected by an animal health technician or other veterinarian under the supervision of the accredited veterinarian however, the responsibility of the sample collection and submission remains with the accredited veterinarian. In all cases, the head (or the sample) should be chilled or frozen immediately.

The owner must contact the laboratory or the accredited veterinarian must contact the CFIA district office in advance before submitting a head. The head must bear animal identification.

3.14

If moribund animals are humanely destroyed on farm by a gun shot to the head, the recipient lab must sample and test both the brain and one lymph node from the head (mandibular, retro pharyngeal or third eyelid) for scrapie.

3.15

If the dead animal is not found immediately, or the accredited veterinarian and the laboratory are not available within 36 hours of death, the head of the animal must be frozen by the owner and submitted as a frozen specimen. Freezing enables the scrapie diagnostic test to be applied to the tissues which otherwise would no longer be suitable for testing.

3.16

Animals older than 12 months which are submitted for routine post-mortem may be considered as dead submissions if tested for scrapie.

3.17

Specimens must meet the requirements specified in the diagnostic protocol approved by the CFIA, which guarantees the reliability and accuracy of the results. If an unsuitable specimen is received, the receiving laboratory is to notify the status assessor and accredited veterinarian responsible for the flock/herd. A follow-up of the details of the individual situation will be undertaken with the responsible accredited veterinarian or status assessor. If negligence on the part of the producer is identified as the cause, or this occurrence is repeated, then the program's requirements are not considered to have been met and the flock/herd will be suspended.

3.18

It is not necessary to submit for testing more than five adult animals from a group of animals that die from a common cause as determined by a veterinarian or veterinary pathologist within the time frame (not to exceed four weeks) of the same epidemiologically linked episode.

Exemption From Submission of Heads

3.19

The status assessor should consider the following as automatic exemptions from the requirement to submit unless the status assessor suspects that the conditions set out were not met or that the exemption is being abused to the detriment of the flock certification program.

A. Destruction of sheep by fire

A certificate or letter from an appropriate fire official must accompany the annual report.

B. The destruction and carrying away of the head of a sheep by a predator

A certificate or letter from an appropriate wildlife officer or other government official responsible for investigating such incidents must accompany the annual report.

C.Theft

A report of the police officer who investigates the theft must accompany the annual report.

D. Loss or destruction of the sample when it is no longer in the control of the owner (e.g. by an accredited veterinarian or laboratory). Recognized laboratories should note on reception of the specimen that the obex is not present and the reason why.

A letter setting out the details of the loss of the sample by the individual responsible must accompany the annual report.

E. Any other reason over which the owner could not reasonably be expected to have control which results in the destruction or disappearance of the body, such as a flood

A letter or report by an acceptable third party which sets out the details of the reason for failure to submit the sample must accompany the annual report.

Genotype Samples and Testing

3.20

Samples (e.g. blood samples) required for genotyping may be taken by a veterinarian accredited to deliver the VSFCP or a third party under the supervision of a veterinarian accredited to deliver the VSFCP (e.g. a veterinary student, a technician). Approved identifiers are required on sheep being genotyped and the official identification number (15 digits) included with the sample submission.

3.21

The genotype of 136AA 171RR breeding rams must be determined twice: by using a combination of predictive parentage and testing by a laboratory approved by the CFIA, or a combination of testing at any laboratory and at a laboratory approved by the CFIA. Genotype results with only codon 171 for those animals determined to be 171RR are considered acceptable. This is due to the knowledge that R cannot be found at site 171 in combination with V at site 136 (V at site 136 is linked with Q at site 171).

Accordance between the results of the two separate determinations of genotype is required. In cases of discordance, a separate sample will be taken from the animal and submitted to the CFIA lab for determination of the genotype.

Breeding ewes that require genotyping may have their genotype determined through the use of predictive parentage or laboratory analysis.

Samples for genotyping of female sheep may be submitted to any laboratory approved by the CFIA.

Genotyping two different tissues (blood, hair follicle or buccal swab) should be considered especially for confirming genotype in 136AA 171QR animals due to the phenomenon of blood chimerism. There are limitations of the standard blood sample in this rare situation of a chimeric animal.

Information Sharing

3.22

Information sharing requires all flock/herd information, including inventories, test results, documents related to purchases and sales of animals or embryos, deaths, to be available to the owner, the CFIA, the status assessor, the regional administrator and the accredited veterinarian. The owner must also agree to allow publication of the status of the flock/herd under the program.

4. Program Specific Pathway 1

Note: This pathway is available to sheep and goats.

4.1

The program includes six levels, from the entry level (level E) to the highest level (certified). A minimum of five years (one year at each level E, D, C, B, A) is necessary for an enrolled flock/herd to reach the certified level in pathway 1. Once a flock/herd has reached the certified level, it maintains this level provided that the applicable requirements continue to be met.

4.2

The status category is effective from the date when the flock/herd is accepted within the program, and the anniversary quarter for subsequent years is the quarter in which the acceptance date falls (January 1-March 31; April 1-June 30; July 1-September 30; October 1-December 31).

4.3

A brain sample from all sheep or goats over 12 months of age that die or are humanely killed on the farm (deadstock) must be submitted for scrapie testing by a laboratory approved by the CFIA.

4.4

One-hundred per cent of animals older than 12 months that die or are humanely destroyed on the farm are to be submitted for scrapie testing. Animals that are unavailable for testing beyond the automatic exemptions detailed in these standards will be considered as per policy detailed by the status assessor. A program participant who does not agree with the decision of the status assessor may appeal the decision.

4.5

If no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, at least one animal 18 months of age or older, which has resided in the flock/herd for no less than 18 months, is to be humanely destroyed (in any manner: slaughter, euthanasia) and a sample submitted for testing. If the flock is genotyped, then select a genetically susceptible animal to be humanely destroyed for testing. If humanely destroying an animal for deadstock testing will have a significant impact on the flock or herd due to its small size, a producer enrolled on pathway 1 may be able to advance using the alternative live animal sampling protocol detailed below.

Alternatively if no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, an enrolled producer may be permitted to remain on the program without advancing to the next level for one additional year (allowing time to raise an animal for slaughter and testing). For certified producers, they would incur a one year status penalty dropping them from certified to Level A.

Alternative live animal sampling protocol
This protocol will be accessible when a process for submission, testing and payment in an approved laboratory is available.

To be eligible for advancement live animal sampling must include the following:

  • All eligible animals in the flock or herd must be sampled and tested by rectal (RAMALT) biopsy or third eyelid biopsy. Exempt animals are those animals with valid test results in the previous 12 months;
  • A minimum of three eligible animals must have been tested with valid test results;
  • Eligible animals are defined as all 171QQ sheep over 14 months of age for third eyelid biopsy and all 171QQ sheep and all goats over 12 months of age for rectal (RAMALT) biopsy;
  • Samples must be taken by an accredited veterinarian on contract and be subjected to testing for scrapie by a laboratory approved by the CFIA for that purpose;
  • Animals sampled and tested must have a valid test result which is considered a negative test result or, if the test is inconclusive, sampling and testing must be repeated a second time; and
  • If this live animal sampling protocol has been used to meet requirements to advance in the program at any level, then to advance from Level A to Certified, the flock or herd must have accumulated at least as many valid test results as there were test eligible animals present in the flock/herd upon enrollmentFootnote 3 (this can be any combination of live animal and post-mortem test results).

4.6

Introduction of female animals or embryos from the following sources, with a supporting zoosanitary health certificate, will have no impact on the certification level:

  • flocks/herds registered in the VSFCP at an equivalent or higher certification level (anniversary quarter will be taken into consideration); or
  • a country the CFIA recognizes as being free from bovine spongiform encephalopathy (BSE) and scrapie; or
  • a flock/herd registered (on the date of export or embryo collection) at an equivalent or higher level in a country/region/zone of origin's scrapie flock certification program, that the CFIA has assessed as being equivalent to the Canadian program; or
  • In vivo sheep embryos of the 136AA 171RR genotype from donors with records that enable trace back to all flocks and establishments that they have resided and the donors are not known to be scrapie positive, scrapie suspect or scrapie exposed susceptible animals

4.7

A) Introduction of males from flocks/herds from the following sources, with supporting documentation, will have no impact on the certification level and these males will acquire the status of the flock/herd:

  • flocks/herds registered in the VSFCP at an equivalent or higher certification level (anniversary quarter will be taken into consideration); or
  • a country the CFIA recognizes as being free from bovine spongiform encephalopathy (BSE) and scrapie; or
  • a flock/herd registered (on the date of export) at an equivalent or higher level in a country/region/zone of origin's scrapie flock certification program, that the CFIA has assessed as being equivalent to the Canadian program; or
  • rams genotyped 136AA 171RR or 136AA 171QR from sheep flocks of any status, but must not be from flocks currently subject to any scrapie disease control measures. Owner must obtain a letter from the seller attesting that the ram's flock is not currently subject to any scrapie disease control measures and the ram's genotype must be determined twice as per 3.20 and 3.21. Rams genotyped 136AA 171RR or 136AA 171QR are not restricted in their movement in and out of the flock except they must not be on a premises currently subject to any scrapie disease control measures.

B) Introduction of males from any flocks/herds and kept in the following manner will have no impact on the certification level:

  • must not be a scrapie positive, scrapie suspect or scrapie exposed susceptible animal. Owner must obtain a letter from the seller attesting that the flock/herd is not currently subject to any scrapie disease control measures;
  • must be maintained separateFootnote 4 from the female animals except during the breeding period;
  • must be maintained separateFootnote 4 from the lambs/kids and lambing/kidding facilities at all times; and
  • these males acquire an individual status level but will start at level E and to advance must not commingle with animals from non-participating flock/herds or a flock/herd of a lower status. These animals are to be identified separately on the annual inventory.
  • males imported from the United States under option 2c) of the Requirements for Small Ruminants Imported from the United States for Breeding, Domestic or Captive Purposes import policy are required to meet the conditions of this policy and be maintained separateFootnote 4 from female animals except during the breeding period and from lambs/kids, and from lambing/kidding facilities at all times, and must never leave the importing premises without written permission from the CFIA. Written permission may be given for activities that would fall under the limited contact definition. Written permission may be given for imported male goats to leave temporarily for hand-breeding purposes, however this would be considered commingling and their individual status would be assigned to reflect this upon their return.

4.8

The flock/herd status certificate accompanying the purchase of the animals or embryos will be the supporting document required to attest to the certification level of the flock/herd of origin.

4.9

Introduction of one or more animals or embryos obtained from flocks/herds registered in the VSFCP at the same certification level but registered in a later anniversary quarter will result in the recipient's anniversary quarter being moved to that of the flock/herd of origin. If one or more animals or embryos from a non-participating flock/herd are introduced, the enrolled producer's anniversary quarter will change to the quarter in which the new animal(s) or embryo(s) were introduced, in addition to the penalty to downgrade to or remain at level E. Anniversary quarter will not be affected for flocks where these embryos or males have been introduced and have met the genotype requirement as set out in 4.6 or 4.7. Anniversary quarter will not be affected for flocks or herds where males have been introduced and met the requirements to be maintained separately as set out in 4.7.

4.10

If animals or embryos from flocks/herds of a lower certification level are introduced, the status of the recipient flock/herd will be downgraded to that of the flock/herd of origin of the lowest category. If animals or embryos from a non-participating flock/herd are introduced, the status of the recipient flock/herd will be reduced to level E. Anniversary quarter will not be affected for flocks where these embryos or males have been introduced and have met the genotype requirement as set out in 4.6 and 4.7. Anniversary quarter will not be affected for flocks or herds where these males have been introduced and met the requirements to be maintained separately as set out in 4.7.

4.11

With the exception of limited contacts (see definitions), commingling of animals from non-participating flock/herds or a flock/herd of a lower status will result in downgrading of the certification level to that of the flock/herd of origin of the lowest category (level E if animals are commingled with animals from a non-participating flock/herd).

4.12

Semen may be sourced from males in non-participating flocks/herds or flocks/herds of any certification level, with no impact on the certification level of the recipient flock/herd, provided that, on the date of insemination, the semen donor is not affected by scrapie (positive animal) or suspected of being affected by scrapie or from a scrapie exposed susceptible animal. The semen must meet the requirements of the national artificial insemination program.

4.13

The producer must make an annual request for advancement or maintenance of the flock/herd status within the VSFCP. The request must be accompanied by the annual report including animal inventory, and all supporting documentation must be submitted to the status assessor.

5. Program Specific Pathway 2A – Third Eyelid

Note: This pathway is not available to goats.

5.1

A blood sample is collected from all animals older than 14 months and submitted for genotyping by a laboratory approved by the CFIA. Samples (e.g. blood samples) required for genotyping must be taken by a veterinarian accredited to deliver the VSFCP or a third party under the supervision of a veterinarian accredited to deliver the VSFCP (e.g. a veterinary student, a technician).

5.2

All animals 14 months of age or older, that are determined to have the 171QQ (136AA 171QQ, 136AV 171QQ, 136VV 171QQ) genotype, must have a sample of lymphoid tissue collected from the third eyelid by the accredited veterinarian on contract and subjected to testing for scrapie by a laboratory approved by CFIA for that purpose. A minimum of 50 animals must be biopsied in order to continue in this pathway.

5.3

If all laboratory tests for scrapie are negative, the flock may officially apply to enter the VSFCP and, if accepted, enters level B.

5.4

Commencing upon acceptance into the program, brain samples from all sheep/goats over 12 months of age that die on the farm (deadstock) must be submitted for scrapie testing by a laboratory approved by the CFIA. If no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, at least one animal 18 months of age or older, which has resided in the flock/herd for no less than 18 months, is to be humanely destroyed (in any manner: slaughter, euthanasia) and a sample submitted for testing. If the flock is genotyped, then select a genetically susceptible animal to be humanely destroyed for testing

Alternatively if no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, an enrolled producer may be permitted to remain on the program without advancing to the next level for one additional year (allowing time to raise an animal for slaughter and testing). For certified producers, they would incur a one year status penalty dropping them from certified to Level A.

5.5

Standards 4.6 to 4.12 for the introductions of animals, embryos and semen are applicable to this pathway.

5.6

For application to advance to level A, any breeding sheep that were purchased from other farms prior to entering the VSFCP but were not 14 months or older (and thus did not have third eyelid test) at the time of the first testing must now be subject to genotyping and third eyelid testing as per steps 5.1 and 5.2 above. These results must be submitted along with the annual report and the request to advance to level A.

5.7

The flock may advance to the certified level as per pathway 1. Once a flock has reached the certified level, it maintains this level provided that the requirements for this level (deadstock surveillance, acquisitions) are met. An annual request, with the accompanying annual report including animal inventory and all supporting documentation, must be submitted to the status assessor.

Program Specific Pathway 2B – RAMALT Biopsy

Note: This pathway is available to sheep and goats. Start at 5.10 if dealing with a goat herd on this pathway.

5.8

A blood sample is collected from all sheep older than 12 months and submitted for genotyping by a laboratory approved by the CFIA. Samples (e.g. blood samples) required for genotyping must be taken by a veterinarian accredited to deliver the VSFCP, or a third party under the supervision of a veterinarian accredited to deliver the VSFCP (e.g. a veterinary student, a technician).

5.9

All sheep 12 months of age or older that are determined to have the 171QQ (136AA 171QQ, 136AV 171QQ, 136VV 171QQ) genotype must have a RAMALT biopsy collected by the accredited veterinarian on contract and be subjected to testing for scrapie by a laboratory approved by the CFIA for that purpose. A minimum of 50 sheep must be biopsied in order to continue in this pathway.

5.10

All goats 12 months of age or older must have a RAMALT biopsy taken by the accredited veterinarian on contract and subjected to testing for scrapie by a laboratory approved by the CFIA for that purpose. A minimum of 50 goats must be biopsied in order to continue in this pathway.

5.11

If all laboratory tests for scrapie are negative, the flock/herd may officially apply to enter the VSFCP and, if accepted, enter level B.

5.12

Upon acceptance into the program, brain samples from all sheep or goats over 12 months of age that die on the farm (deadstock) must be submitted for scrapie testing by a laboratory approved by the CFIA. If no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, at least one animal 18 months of age or older, which has resided in the flock/herd for no less than 18 months, is to be humanely destroyed (in any manner: slaughter, euthanasia) and a sample submitted for testing. If the flock is genotyped, then select a genetically susceptible animal to be humanely destroyed for testing.

Alternatively if no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, an enrolled producer may be permitted to remain on the program without advancing to the next level for one additional year (allowing time to raise an animal for slaughter and testing). For certified producers, they would incur a one year status penalty dropping them from certified to Level A.

5.13

Standards 4.6 to 4.12 for the introductions of animals, embryos and semen are applicable to this pathway.

5.14

To apply to advance to level A, any breeding animals that were purchased from other farms prior to entering the VSFCP, but were not 12 months or older (and thus did not have a rectal biopsy) at the time of the first testing, must now be subject to genotyping and rectal biopsy (if sheep), as set out in 5.8 and 5.9, and rectal biopsy (for goats), as set out in 5.10. These results must be submitted along with the annual report and the request to advance to level A.

5.15

The flock/herd may advance to the certified level as per pathway 1. Once a flock/herd has reached the certified level, it maintains this level provided that the requirements for this level (deadstock surveillance, acquisitions) are met. An annual request, with the accompanying annual report including animal inventory and all supporting documentation, must be submitted to the status assessor.

6 & 7. Program Specific Pathway 3

Note: This pathway is not available to goats.

There are two distinct ways in which a producer may prepare their flock for application into this pathway.

6. Whole-Flock Genetic Screening

6.1

A blood sample is collected from all breeding sheep and submitted for genotyping by a laboratory approved by CFIA. The genotype of 136AA 171RR breeding males must be determined twice and the genotype of breeding females must be determined once. (See sections 3.20 and 3.21 under General Rules for more details.)

6.2

Upon receipt of the results, all breeding females and males that are determined to be 171QQ (136AA 171QQ, 136AV 171QQ, 136VV 171QQ) or 136AV 171QR are removed from the breeding flock.

If any of the breeding stock to be retained have been bred, it will be necessary to determine the genotype of their progeny to determine if they may also be retained.

6.3

After removing 171QQ (136AA 171QQ, 136AV 171QQ, 136VV 171QQ) and 136AV,171QR sheep from the flock, an updated inventory documenting that all remaining breeding sheep are 136AA 171RR or 136AA 171QR must be conducted under the supervision of a veterinarian accredited to deliver the VSFCP. At this point the producer may officially apply to enter the VSFCP and, if accepted, enter level A.

6.4

Commencing upon acceptance into the program, brain samples from all sheep over 12 months of age that die on the farm (deadstock) must be submitted for scrapie testing by a laboratory approved by CFIA. If no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, at least one animal 18 months of age or older, which has resided in the flock/herd for no less than 18 months, is to be humanely destroyed (in any manner: slaughter, euthanasia) and a sample submitted for testing.

Alternatively, if no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, an enrolled producer may be permitted to remain on the program without advancing to the next level for one additional year (allowing time to raise an animal for slaughter and testing). For certified producers, they would incur a one year status penalty dropping them from certified to Level A.

6.5

Newly purchased breeding stock must be genotyped 136AA 171QR or 136AA 171RR by a laboratory approved by CFIA. This restriction also applies to semen.

6.6

Ewe offspring (including embryos) from a mating involving at least one 171RR parent may be retained in the flock for breeding purposes without genotyping.

6.7

Offspring (including embryos) from all other matings (other than one involving at least one 136AA 171RR parent) must be genotyped or removed from flock by 12 months of age. 171QQ offspring must be removed by 12 months of age.

6.8

After one year of continuing the requirements for restrictions on genotype of introduced animals and deadstock surveillance, and the compilation of a second annual inventory that documents the appropriate flock membership, the owner may apply for advancement in the VSFCP to certified level status.

6.9

Once a flock has attained the certified level, it maintains this level provided that the requirements for this level (genotyping of offspring from non RR matings and genotype restriction on purchased breeding stock or germplasm; deadstock surveillance) are followed. An annual request, with the accompanying annual report (including animal inventory and all supporting documentation), must be submitted to the status assessor.

7. Rams-Only Genetic Screening

7.1

A producer starts by selecting breeding rams that are documented 136AA 171RR. The genotype of 136AA 171RR breeding males must be determined twice. (See sections 3.20 and 3.21 under General Rules for more details.)

7.2

Over subsequent breeding cycles, the flock is culled such that all remaining sheep can be documented (by flock records) to be offspring of a 136AA 171RR ram.

7.3

All subsequent breeding males, be they natural replacements, purchases or loans, must be 136AA 171RR. Semen must be sourced from rams genotyped 136AA 171RR. All breeding females, other than natural replacements, and embryos must be established by genotyping as 136AA 171QR or 136AA RR.

7.4

At this point, an annual inventory documenting the removal of 171QQ (136AA 171QQ, 136AV 171QQ, 136VV 171QQ) and 136AV 171QR and ungenotyped sheep must be conducted under the supervision of a veterinarian accredited to deliver the VSFCP. At this point, the producer may officially apply to enter the VSFCP and, if accepted, enter level A.

7.5

Commencing upon acceptance into the program, a brain sample from all sheep over 12 months of age that die on the farm (deadstock) must be submitted for scrapie testing by a laboratory approved by CFIA. If no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, at least one animal 18 months of age or older, which has resided in the flock/herd for no less than 18 months, is to be humanely destroyed (in any manner: slaughter, euthanasia) and a sample submitted for testing.

Alternatively, if no suitable samples have been submitted for testing for a period of time equal to or exceeding 12 months, an enrolled producer may be permitted to remain on the program without advancing to the next level for one additional year (allowing time to raise an animal for slaughter and testing). For certified producers, they would incur a one year status penalty dropping them from certified to Level A.

7.6

After one year of continuing the requirements for restrictions on genotype of introduced animals and deadstock surveillance, and the compilation of a second annual inventory that documents the appropriate flock membership, the owner may apply to advance to the certified level of the VSFCP.

7.7

Once a flock has attained the certified level, it maintains this level provided that the requirements for this level (selection of replacement breeding rams genotyped twice and purchased ewes, and deadstock surveillance) are met. An annual request, with the accompanying annual report including animal inventory and all supporting documentation, must be submitted to the status assessor.

Definitions

Commingled (mixed):
animals grouped together with physical contact between the animals. This does not include limited contact (e.g. contact through a fence, pen separation during a show/sale). Commingling includes sharing the same section in a transportation unit where physical contact can occur. (Mélangés (mêlés))
Contiguous:
Premises which share common boundaries and where co-mingling of small ruminants can occur between the two premises. (Aire contiguë)
Established flock or herd:
all animals that are maintained on a single premises and all animals under common ownership or supervision on two or more premises with animal interchange between the premises or indirect contact including shared use of housing, facilities or pasture.(Troupeau établi)
Flock or Herd:
as defined in the Health of Animals Regulations. (Troupeau)
Flock/herd status certificate:
document issued by the regional administrator specifying the location and status of the flock/herd, indicating the date of issue, and identifying animals leaving the flock/herd following their sale. (Certificat de statut du troupeau)
Limited contact:
incidental contacts between animals off the premises of the flock/herd such as at fairs, shows, exhibitions and sales and semen collection facilities. Limited contact does not include any contact, incidental or otherwise, with an animal during or up to 30 days after she lambed, kidded or aborted or when there is any visible vaginal discharge. Limited contacts do not include any activity where uninhibited contact occurs, such as sharing an enclosure, sharing a section of a transport vehicle, or residing in the other flock/herd for breeding or other purposes. (Contact limité)
Scrapie exposed susceptible animal:
Any goat and any sheep of 171QQ or 136AV 171QR genotype that has resided on a premises while it was declared scrapie infected by a competent authority (i.e. CFIA). (Animal sensible exposé à la tremblante)
Scrapie positive:
An animal for which scrapie-positive results were reported by the CFIA's National and OIE Reference Laboratory for Scrapie, using at least two CFIA-approved scrapie tests (e.g. ELISA, immunohistochemistry, Western blot) applied to the brain and/or lymphoid tissue. (Animal positif à la tremblante)
Scrapie suspect:
Any animal that has scrapie as a differential diagnosis. (Animal suspect à l'égard de la tremblante)
Unique identification devices:
permanent, unique, traceable and secure (e.g. electronic identification, tattoo, tamper evident tag). Until the national mandatory identification program for goats is implemented, neck chains and collars are acceptable as one form of identification in goats. (Dispositif d'identification unique (identifiant unique))
136AA:
includes all results that identify the animal as a homozygote for alanine (A) at codon 136 of the scrapie prion gene. (AA en 136)
136AV:
includes all results that identify the animal as a heterozygote for valine (V) and alanine (A) at codon 136 of the scrapie prion gene. (AV en 136)
136VV:
includes all results that identify the animal as a homozygote for valine (V) at codon 136 of the scrapie prion gene. (VV en 136)
171QQ:
includes all results that do not identify arginine (R) at codon 171 of the scrapie prion gene (includes glutamine and histidine; QQ, QH, HH). (QQ en 171
171QR:
includes all results that do not identify the animal as a homozygote for arginine (R) at codon 171 of the scrapie prion gene, identifying arginine on one allele and the absence of arginine on the other (includes glutamine and histidine; QR or HR). (QR en 171)
171RR:
includes all results that identify the animal as a homozygote for arginine (R) at codon 171 of the scrapie prion gene. (RR en 171)

7.5 Appendices

Appendix A: Brain Sampling Procedures

Entire heads may be submitted fresh or frozen to an approved laboratory.

Scrapie is not considered to be a human pathogen; however, normal sanitary precautions against a possible range of pathogens should be taken. Wear protective clothing, gloves and face protection when collecting brain specimens. Always avoid direct contact with brain tissues. Personnel at tissue harvesting sites should take precautions to avoid ingestion of the agent.

Precautions against the transmission of disease to small ruminants and the environment are warranted. It is recommended that the animal's head be placed on a disposable plastic drop sheet. The sheet should be large enough to cover the work area. As prions are particularly resistant to standard physical and chemical methods of decontamination, see Appendix E for appropriate disinfectants.

This is an image of the grapefruit spoon and knife

Obex Harvesting Technique

Recommended tools:

  • autopsy knife for disarticulation of the head (if required);
  • obex removal spoon or knife; and
  • rat tooth forceps.

Additional tools that you may choose to use:

  • scalpel; and
  • scissors.

The obex removal spoon or knife may be fashioned from the Zwilling J.A. Henckels – Jessica Grapefruit spoon or knife, respectively. Alternatively, any butter knife or suitably long and concave spoon (6 mm concavity) can be modified. The edges of the knife must be sharpened. The edges of the spoon should be cut down to measure 22-26 mm at the widest point and sharpened to a blade.

This is an image of a sheep's head dorsal side down on a table with the opening of the spinal canal facing you

With the aid of an autopsy knife, disarticulate the head at the level of the atlanto-occipital articulation. Place the head dorsal side down on a table with the foramen magnum (the opening of the spinal canal) facing you.

Using the forceps with your left hand, grasp the dura mater (the thick lining around the spinal cord) and with the scissors in your right hand, make a single cut down the centre line to form two flaps. (This step is not mandatory.) Remove the congealed blood from around the cord.

This an image of using the forceps to grasp the dura mater with one hand and with the other hand using scissors to make a cut in the dura mater

These are images of using the forceps to hold the dura mater, while severing the cranial nerves from the spinal cord

With the forceps in your left hand holding the dura, sever the cranial nerves from the cord. This can be done with scissors or with the obex spoon/knife by passing the spoon/knife around the cord, keeping the flat side of the spoon/knife against the cord. (See next picture for position of obex spoon/knife in relation to the cord.) This is the most important step in freeing up the cord. The cord must be completely free from attachments (by cranial nerves) in all directions. If you do not sufficiently free up the cord, you will not be able to sample anteriorly enough to get the obex, or one side will be missing.

Insert the obex spoon/knife face down into the vertebral canal and move it forward, lodging the tip as far cranially as it will go. This should position the tip of the spoon/knife over the part of the cord just anterior to the obex and just behind the cerebellar attachments.

This is an image of inserting the obex spoon face down into the vertebral canal

Identifying the nerves of the brain - Example 1. Description follows.

Brain Sampling Procedures - Example 1

This image represents the cranial nerves. Listing the cranial nerves and other key brain structures from top to bottom: Optic chiasm, Trochlear nerve, Abducens nerve, Vestibulocochler nerve, Vagus nerve, Choroid plexus, Accessory nerve. The sampled portion of cord showing cranial nerves is identified with a rectangle.

Identifying parts of the brain - Example 2. Description follows.

Brain Sampling Procedures - Example 2

This image is the diagram of vertebral canal and cerebellar attachments. Listing the parts of the vertebral canal and cerebellum from top left to bottom right: the Foramen magnum, Spinal cord, Obex, Cerebellar attachments, Cerebellum, Top of the skull.

Pick up the head and (if right-handed) hold in left hand, dorsal side down. While pushing down with your index finger, manoeuvre the tip of the obex spoon/knife back and forth over the cord to sever it from the rest of the brain just rostral to the obex and caudal to the cerebellar attachments. Rotate the skull with your other hand in the opposite direction of the spoon/knife to facilitate the cutting of the cord.

These are images of manoeuvring the tip of the obex spoon back and forth over the cord to sever it from the rest of the brain

These are images of manoeuvring the tip of the obex spoon back and forth over the cord to sever it from the rest of the brain

This is an image of the obex spoon gently pulling the severed portion of the brain from the canal

Use the obex spoon/knife to gently pull the severed portion of the brain from the canal. The obex is recognizable as a V-shaped depression. This portion is the single most important site for diagnostic testing.

This is an image of the sampled brainstem including obex. The obex is seen as a V -shaped depression.

This is an image of the sampled brainstem including obex.  The obex is seen as a V -shaped depression.

This is an image of the brainstem with the spinal cord, obex and brainstem labelled

Contact the CFIA-approved laboratory to which you will be submitting the samples and request information on preparing the sample for submission (fresh or frozen).

Samples can be frozen and batch-shipped in a frozen state to a CFIA-approved laboratory for enzyme-linked immunosorbent assay (ELISA) testing (if necessary).

As traceability is critical when there is a scrapie positive, it is essential to ensure that the sample submitted is irrefutably linked to the correct animal by documenting national identifiers or other unique identifiers.

Tissues for scrapie surveillance testing may be packaged and shipped as exempt animal specimens in accordance with the Transportation of Dangerous Goods Regulations. The basic four-part packaging system may be used: Following fixation, the specimen must be packaged in a primary watertight receptacle (Whirl-Pak-type bag) with labelling. Enclose this in a second durable watertight packaging (Whirl-Pak-type bag) with adequate absorbent material to absorb all fluid in case of breakage. Outer packaging, such as a fibreboard box, protects the contents from external physical damage. The description of the contents on the shipper's waybill should include the notation "exempt animal specimen."

Appendix B: Sampling Procedures for Genotyping

Samples required for genotyping may be taken by a veterinarian accredited to deliver the VSFCP or a third party under the supervision of a veterinarian accredited to deliver the VSFCP (e.g. a veterinary student, a technician). Approved identifiers are required on sheep being genotyped and the official identification number (15 digits) included with the sample submission

These are images of sheep having blood taken by jugular venipunctures

Jugular Venipuncture

To facilitate the rapid collection of blood samples from multiple sheep in as little time as possible, it is suggested to not waste time upending the sheep. Restrain sheep for venipuncture in a standing position.

Occlude thoracic inlet, palpate or approximate the location of the jugular vein, and insert Vacutainer needle.

A single-use needle is required for each animal, to prevent cross-contamination of DNA.

Collect a full 7-10 ml of blood in an ethylenediaminetetraacetate (EDTA) tube (lilac or purple top).

Make sure that the sample and individual animal identification are irrefutably connected.

Samples should be stored at 4°C until shipped. Ship to laboratory as soon as possible.

Check with individual laboratories for preferences regarding sample submission, including preferred day of submission.

Tissue Samples for Genotyping

Other tissues such as brain and hair can be used. Check with individual laboratories for preferences regarding tissue selection. If the head or brain sample is being forwarded for scrapie testing, it would be easiest for the laboratory to forward a sample of brain for genotyping.

Appendix C: Third Eyelid Lymphoid Follicle Sampling Procedures

This live animal sampling procedure is performed only in sheep. In most cases, the RAMALT biopsy sampling procedure (Appendix D) is the preferred live animal sampling procedure.

As potentially scrapie infective lymphoid tissue is being harvested and the site of harvesting (the eye) is a potential route of introduction of the scrapie agent, precautions to prevent potential transmission are required.

Instruments can be handled in one of the following ways:

  • Single-use instruments may be used and discarded after use on a single animal.
  • Multi-use instruments may be disinfected with a product and protocol known to be prionicidal. (See Appendix E for disinfectants.)
  • Alternatively, the forceps and scissors used on an individual sheep may be placed in a bag, accompanied by the individual sheep identification. These instruments can then be stored until the results of the tests are known. Disinfect instruments used on scrapie- negative sheep and return to normal use. Disinfect instruments used on scrapie-positive sheep and then dispose of them.

Technique

One person is required to restrain the sheep.

Verify by checking individual identification that this animal has been genotyped as a 171QQ.

Instill several drops of a local ophthalmic anaesthetic agent (proparacaine, lidocaine, or xylocaine) into the selected eye.

Apply a drop of 1% histamine solution to the bulbar surface of the third eyelid. This will dramatically facilitate the visualization of the now hyperemic, slightly raised/irregular area that represents the lymphoid follicles.

Note: The histamine solution can be compounded by a veterinary pharmacy, such as the following:

  • Veterinary Pharmacy, Imperial Road, Guelph, Ontario, 519-824-7887; or
  • Strathcona Prescription Centre 8225-105 Street, Edmonton, Alberta, T6E 4H2, 780-432-0394 or 888-433-2334.

Allow 5-6 minutes for applied drops to take effect.

This is an image of the edge of the sheep's third eyelid being grasped by forceps

Grasp the edge of the third eyelid with tissue forceps, evert, and visualize the ventral (bulbar) surface of the third eyelid.

This is an image of lymphoid follicles being cut from the third eyelid

Using scissors (Metzenbaum preferred), blades flush with the third eyelid, cut identified lymphoid follicles from the third eyelid. Place the biopsy samples in a labelled cassette lined with a biopsy pad (i.e. Leica Microsystems – 1 x 1.25 Cat # 3801000). Place the cassette(s) in a leak-proof container with 10% neutral buffered formalin for the fixation period (see notes below), at a ratio of 1:10 tissue/formalin, prior to shipping.

Forward sample(s) to a laboratory capable of immunohistochemistry testing of testing lymphoid tissues for scrapie.

Notes:

  • When submitting formalinized third eyelid biopsy tissues, the specimen(s) must be fixed for at least 24 hours and for no more than five days, depending on the size of the sample. Penetration of formalin is at least 5 mm of tissue thickness per day and should be in a 1:10 (Tissue: Formalin) ratio.
  • Cassettes should never be labelled with a permanent marker, as the ink may smudge and thus disappear during the processing time. An HB #2 pencil (or a histological marker which is alcohol safe) is most appropriate when labelling cassettes.
  • Containers that are adequate for the fixation period should be clean with no debris, leak-proof, sealable, and allow easy access to cassettes. Approximately 20 cassettes can be placed in a 500 mL container and 30 in a 750 mL container to achieve an adequate tissue-to-formalin ratio. Starplex Scientific® in Etobicoke, Ontario, sells histology containers that encompass the necessary parameters of specimen fixation containers.

Appendix D: RAMALT Biopsy Sampling Procedures

This live animal sampling procedure is performed on sheep and goats. In most cases, the RAMALT biopsy sampling procedure is the preferred live animal sampling procedure.

As potentially infective lymphoid tissue is being harvested, and as the site of harvesting (recto-anal tissue) is theoretically a possible route of introduction of the scrapie agent, precautions to prevent potential transmission of scrapie are required in sampling potential source flocks.

Instruments can be handled in one of the following ways:

  • Single-use instruments may be used and discarded after use on a single animal.
  • Multi-use instruments may be disinfected with a product and protocol known to be prionicidal (See Appendix E for disinfectants).
  • Alternatively, the forceps and scissors used on an individual animal may be placed in a bag accompanied by the individual animal's identification. These instruments may then be stored until the results of the tests are known. Disinfect instruments used on scrapie-negative sheep and return to normal use. Disinfect instruments used on scrapie-positive sheep and then dispose of them.

Technique

One person is required to restrain the animal by holding it against a wall or in a corner.

Verify the individual identification of the animal. For sheep, also verify by checking individual identification that this animal has been genotyped as a 171QQ.

Anesthetic/analgesic cream (lidocaine and prilocaine) is not required but if preferred can be applied to the distal rectal mucosa with a gloved finger. An example would be Eutectic Mixture of Local Anesthetics (EMLA), a 1:1 oil/water emulsion of a eutectic mixture of lidocaine and prilocaine based cream, produced by Astrazeneca Canada Inc. Lidocaine and prilocaine, both solids at room temperature, form a eutectic that is an oil with a 16°C melting point.

If using a rectal speculum, insert into rectum after liberal application of analgesic cream, which also doubles as a lubricant.

Allow approximately five minutes for the analgesic/anaesthetic cream to take effect.

Palpate/visualize the recto-anal junction. Take samples approx 1-2 cm anterior (aboral) to the recto-anal junction. Preferred locations for sampling include the dorsolateral (10 and 2 o'clock positions) and ventrolateral (4 and 8 o'clock positions) surfaces of the mucosa. Take samples at 10, 2 and, if necessary, 4 and 8 o'clock positions. Avoid sampling the roof or the floor of the mucosa (the 6 and 12 o'clock positions). Using forceps, pick up the rectal mucosa/crypt, creating a "tent" of tissue. Using scissors, excise the tent of tissue. Place the biopsy samples in a labelled cassette lined with a biopsy pad (i.e. Leica Microsystems – 1 x 1.25 Cat # 3801000). Place the cassette(s) in a leak-proof container with 10% neutral buffered formalin for the fixation period (see notes below), at a ratio of 1:10 tissue/formalin, prior to shipping.

For more information, view the RAMALT Biopsy Sample Technique.

Forward the sample(s) to a laboratory that is capable of immunohistochemistry testing of lymphoid tissues for scrapie.

Notes:

  • When submitting formalinized RAMALT biopsy tissues, the specimen(s) must be fixed for at least 24 hours and for no more than five days, depending on the size of the sample. Penetration of formalin is at least 5 mm of tissue thickness per day and should be in a 1:10 (Tissue: Formalin) ratio.
  • Cassettes should never be labelled with a permanent marker, as this will likely smudge and will disappear during the processing time. An HB #2 pencil (or a histological marker which is alcohol safe) is most appropriate when labelling cassettes.
  • Containers that are adequate for the fixation period should be clean with no debris, leak-proof, sealable, and allow easy access to cassettes. Approximately 20 cassettes can be placed in a 500 mL container and 30 in a 750 mL container to achieve an adequate tissue-to-formalin ratio. Starplex Scientific® in Etobicoke, Ontario, sells histology containers that encompass the necessary parameters of specimen fixation containers.

Appendix E: Sanitary Precautions/Disinfectants

Scrapie is not considered to be a human pathogen; however, when sampling, normal sanitary precautions against a possible range of pathogens should be taken. Wear protective clothing, gloves and face protection when collecting brain specimens. Always avoid direct contact with brain tissues. Personnel at tissue harvesting sites should take precautions to avoid ingestion of the agent.

Prion agents are particularly resistant to standard physical and chemical methods of decontamination. Traditional disinfectants such as Virkon are not effective against prion agents. Instruments and surfaces must be disinfected with either sodium hypochlorite or sodium hydroxide, recommended protocols include the following:

It is recommended that the animal's head be placed on a disposable plastic drop sheet. The sheet should be large enough to cover the work area. Used disposable protective clothing, gloves, and animal remains should be buried or incinerated.

Instruments

Instruments and materials subject to re-use should be kept moist between the time of exposure to infectious materials and subsequent cleaning and decontamination.

  • Wipe clean thoroughly, and then soak in 2% available chlorine for 1 hour at 20°C;
  • Wipe clean thoroughly, soak in 2M NaOH for 1 hour at 20°C, rinse with water, and then autoclave at 134°C–138°C for 18 min; or
  • Wipe clean thoroughly, soak in 1M NaOH or 2% available chlorine for 1 hour, rinse with water, transfer to water, and autoclave at 121°C for 1 hour.

Surfaces:

  • Clean thoroughly, flood surfaces with 2% available chlorine for 1 hour at 20°C, and then rinse with water; or
  • Clean thoroughly, flood surfaces with 2M NaOH for 1 hour at 20°C, and then rinse with water.

Chemicals

  • Sodium hydroxide (NaOH) can be purchased from Fisher Scientific in crystal form. To make a 2 Molar concentration of NaOH, dilute 80 grams NaOH crystals in one litre of water and stir well.
  • Sodium hypochlorite (NaOCl) can be prepared from industrial grade or commercially available bleach (such as Javex). Dilute the bleach to provide a final concentration of 2% (20,000 ppm) available chlorine. For example, most commercially available bleaches have 6% available chlorine listed on the label. In this case, mix one part bleach and two parts water (ratio 1:2) to attain the 2% concentration of available chlorine.

Appendix F: Cleaning and Disinfection on a Premises

Cleaning and Disinfection (C&D) on a premises is applicable in certain situations when a VSFCP flock/herd with status D or higher is moving to a new premises and wishes to keep that status. If C&D is required, owners who do not undertake C&D and have it approved will not be permitted to keep their flock status. Details are provided in the VSFCP National Standards Section 2.

If C&D is required on the premises it must be supervised by the accredited veterinarian and follow an approved cleaning disinfection protocol as follows:

  • C&D applies to structures where small ruminants are identified to have been contained (indoors or outdoors) or lambed/kidded.
  • Bury or compost bedding, manure, and waste material from these lambing/kidding/housing areas. If composting is chosen, the material is composted for six months and then disposed of on land to which sheep and goats do not have access.
  • Scrape off surface soil (1-2 inches below the depth to which the surface is broken up) from areas identified as outdoor lambing/kidding or housing areas, and bury or dispose of the soil on land to which sheep and goats do not have access.
  • Remove organic debris from, and then superficially disinfect concrete, metal, and wooden structures, including water troughs and drinking bowls, identified to have been in contact with small ruminants. To disinfect use sodium hypochlorite solution (NaOCl) or sodium hydroxide (NaOH) as described in Appendix 2A.
  • It is suggested that the accredited flock/herd veterinarian approve the cleaning before proceeding with the disinfection. This course of action permits the cleaning to be repeated, if it proves inadequate, without having to repeat the more difficult disinfection step.

Appendix G: List of Laboratories

CFIA-Approved Laboratories for Scrapie Genotyping

Animal Health Laboratory
Laboratory Services Division
University of Guelph
419 Gordon Street, Building 89
P.O. Box 3612
Guelph, Ontario, N1H 6R8
Telephone: 519-824-4120, ext. 54530
Facsimile: 519-827-0961

USDA Laboratories - PDF (7 kb)
Laboratories approved by the United States Department of Agriculture (USDA) for scrapie genotyping are acceptable to the CFIA Terrestrial Animal Health Division for export and flock certification testing. The current list of USDA-approved labs for scrapie genotyping can be found on the USDA Animal and Plant Health Inspection Service website under Approved Genotyping Laboratories.

CFIA-Approved Laboratories for Scrapie Testing Using the BioRad ELISA

Alberta Agriculture and Rural Development
Agri-Food Laboratories Branch
TSE Laboratory
6909 - 116th Street
Edmonton, Alberta, T6H 4P2
Telephone: 780-422-4830
Facsimile: 780-415-4527

Animal Health Laboratory
Laboratory Services Division
University of Guelph
419 Gordon Street, Building 89
P.O. Box 3612
Guelph, Ontario, N1H 6R8
Telephone: 519-824-4120, ext. 54530
Facsimile: 519-827-0961

Prairie Diagnostic Services Inc.
52 Campus Drive
Saskatoon, Saskatchewan, S7N 5B4
Telephone: 306-966-7316

Ministère de l'Agriculture des Pêcheries et de l'Alimentation du Québec (MAPAQ) (French only)
Laboratoire d'épidémiosurveillance animale du Québec
3220 Sicotte Street
Saint-Hyacinthe, Quebec, J2S 7X9
Telephone: 450-778-6542
Facsimile: 450-778-6535

Note: Samples may also be submitted through a CFIA district office to CFIA laboratories in Ottawa (Fallowfield), Lethbridge, or Saint-Hyacinthe as part of the National Scrapie Surveillance Program.

CFIA-Approved Laboratories for Scrapie Third Eyelid and RAMALT Biopsy Testing Using Immunohistochemistry

The CFIA Ottawa Laboratory (Fallowfield) is currently the only laboratory conducting the immunohistochemistry (IHC) test. Contact your district office to see if testing through CFIA is possible.

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