Report on the Investigation of the Nineteenth Case of Bovine Spongiform Encephalopathy (BSE) in Canada
November 2015
Report on the Investigation of the Nineteenth Case of Bovine Spongiform Encephalopathy (BSE) in Canada
November 2015
Table of Contents
- List of Tables
- List of Figures
- Acronyms
- 1. Introduction
- 1.1. Details of the BSE Case
- 1.2. Case Investigation Overview
- 1.3. Overview of Canada's Feed Ban and Regulations
- 1.4. Pathways for On-farm Exposure to the BSE Agent Associated with BSE Case #19
- 1.5. Pathways for Off-farm Exposure to the BSE Agent Associated with BSE Case #19
- 1.6. Pathways Investigated for BSE case #19
- 2. Feed Investigation
- 3. Identifying and Tracing Cohort Animals
- 4. Investigation Summary
- 5. Impact of Current Findings
- Appendix 1. Enhanced Feed Ban Compliance Inspection Programs
List of Tables
Table 1. Commercially Prepared Feed Sources to Which the Case Animal had Potentially been Exposed
Table 2. Rendered Animal By-Products Sources to Which the Case Animal had Potentially been Exposed
Table 3. Disposition of Animal Traces for BSE #19 Birth Cohort (n=746)
List of Figures
Figure 1. Sources, Processing, Transportation and Disposal of SRMs
Figure 2. Timeline (birth and death) of BSE Cases #17 and #19 Born on the Same Farm
Acronyms
- BAB
- Born After the Ban
- BARB
- Born After the Reinforced Ban
- BSE
- Bovine Spongiform Encephalopathy
- CFIA
- Canadian Food Inspection Agency
- EFB
- Enhanced Feed Ban
- ISO
- International Organization for Standardization
- MBM
- Meat and Bone Meal
- OIE
- World Organisation for Animal Health
- PM
- Prohibited Material
- QA
- Quality Assurance
- SRM
- Specified Risk Material
- TSE
- Transmissible Spongiform Encephalopathies
1.0 Introduction
1.1 Details of the BSE Case
A sample taken from a cow in Alberta, Canada was identified as positive for Bovine Spongiform Encephalopathy (BSE). The case animal was reported by the owner to have been non-ambulatory (downer) in the days preceding its death. After consultation between the producer and the local veterinary practitioner it was determined that the animal met the inclusion criteria of Canada's National BSE Surveillance Program. The animal was euthanized on February 4, 2015 and arrangements were made to collect and submit appropriate tissue samples for evaluation.
On February 7, 2015, the Alberta Agriculture Edmonton Laboratory (now Alberta Agriculture and Forestry TSE Laboratory) informed the Canadian Food Inspection Agency (CFIA) of a BSE surveillance sample (collected through the Canada-Alberta BSE Surveillance Program) with an initial reaction on the BIO-RAD TeSeE ELISA rapid test that remained positive on repeat testing.
As per Transmissible Spongiform Encephalopathies (TSE) ISO quality assurance (QA) guidelines, homogenates and samples were forwarded to the CFIA and OIE (World Organisation for Animal Health) BSE Reference Laboratory in Lethbridge, Alberta. The sample was confirmed as BSE positive using the OIE Immunoblot (SAF and mAB 6H4) test on February 11, 2015. In addition to the OIE Immunoblot, the National BSE Reference Laboratory evaluated the sample using the Prionics-Check Western® rapid test, Hybrid Western Blot, the Prionics Check PrioSTRIP® rapid test, and the BioRad TeSeE ELISA. All test results were determined to be positive. Hybrid Western Blot results characterized the case as C-type (classical) BSE.
The carcass was secured at the sampling site, obtained by and transferred to CFIA's laboratory in Lethbridge for incineration. No part of the carcass entered the human food supply or animal feed chain.
The positive animal (Case #19) was confirmed to be a pure bred Black Angus beef cow born on March 25, 2009, therefore being 70 months of age at the time of death. It had been sold from its birth farm, via an auction mart, to the farm where it was sampled, just over a year prior to detection (Jan 22, 2014). This was the second BSE case born on the birth farm (the previous was case #17, born in March 2004).
The birth farm of the case animal was a cow-calf operation with both purebred Black Angus and commercial beef cattle. At the time of detection of this case, there were 290 breeding cows on the birth farm.
1.2 Case Investigation Overview
1.2.1 CFIA Investigation as Specified by the OIE
The CFIA immediately initiated an epidemiological investigation based on the recommended BSE guidelines (Terrestrial Animal Health Code 2014) of the OIE and the CFIA's BSE Manual of Procedures. Specifically, the CFIA followed the recommended BSE guidelines for a country with controlled risk status and investigated:
- Feed: all sources of feed to which the infected animal was or may have been exposed during its first year of life;
- Feed cohort: all cattle which, during their first year of life, were reared with the BSE case during its first year of life, and which investigation showed consumed the same potentially contaminated feed during that period; and/or
- Birth cohort: all other cattle that were born on the same farm and within 12 months of the infected animal's birth.
1.2.2 Identifying Potential Risk Pathways for Exposure to the BSE agent
BSE case #19 had two unique characteristics when compared with previous cases Canada has experienced to date:
- This was the second BSE case to be born on the same birth farm (as was case #17, born in March 2004). Canada has not previously identified more than one BSE case born on the same farm.
- The affected animal was born after the enhanced feed ban (EFB): The EFB, implemented on July 12, 2007, ensures that specified risk material (SRM) is excluded from animal feed, pet food and fertilizers. Case #19 was born in March 2009, which is 20 months after the EFB was implemented.
To complete this investigation, on-farm and off-farm risks pathways potentially associated with the unique characteristics of this case were examined. The following sections provide an overview of Canada's feed ban and the potential risk pathways that were considered in the course of the investigation.
1.3 Overview of Canada's Feed Ban and Regulations
In 1997, Canada implemented an initial feed ban as a precautionary measure to limit the potential spread of BSE through the domestic cattle population, should there have been a previously undetected presence of BSE in the country. This ban prohibited the feeding of mammalian-derived proteins (“
prohibited material” or PM) to ruminant animals (cattle, sheep, goats, deer, elk and other species), with the exception of proteins derived from a porcine or equine; gelatin or gelatin products derived exclusively from hides or skins of any species; blood or blood products and rendered fats from any speciesFootnote 1. Canada's ban also prohibited incorporation of poultry litter and restaurant waste into feed for ruminants.
The detection of Canada's first native-born case of BSE in 2003, followed by a small number of BSE cases between 2003 and 2005 were a manifestation of a low level of exposure to the BSE-agent in the cattle population prior to and around the time the feed ban was implemented. In 2006, the Canadian Food Inspection Agency (CFIA) undertook a comprehensive review of the feed ban in order to look at the control measures put in place and examine the CFIA's inspection program to assess compliance with the Health of Animals Regulations. Canadian, U.S. and other international scientific and technical analyses, including a review of the UK experience, confirmed that the ban would have arrested any further amplification and significantly reduced the opportunities for recycling of the BSE-agent in the cattle population. While the impact of the feed ban may not have been absolute, ongoing surveillance confirms the low and declining incidence of BSE. Multiple scientific analyses have concluded that Canada's feed ban would eventually lead to the eradication of BSE in the countryFootnote 2Footnote 3. However, Canada decided to take the additional step necessary to accelerate this process by requiring that SRM be excluded from the entire terrestrial and aquatic animal feed chains, as well as fertilizers from July 2007. It is important to note that prior to 2007, SRM were prohibited from being fed to ruminants as they fell under the scope of the original feed ban as prohibited materials. SRM are now segregated at source and redirected to disposal or destruction to ensure that the remaining PM no longer contains SRM.
SRM includes the skull, brain, trigeminal ganglia, eyes, tonsils, spinal cord and dorsal root ganglia of cattle aged 30 months or older, and the distal ileum of cattle of all ages. Collectively these tissues contain more than 99.9% of the BSE infectivity in an infected animal. Considering that any remaining potential infectivity in non-SRM tissues would be at extremely low levels, the likelihood of an animal becoming infected would be negligible even if it consumed feed contaminated with PM.
Preventing SRM from entering the animal feed and pet food production chain enhanced the 1997 feed ban by minimizing the risk of BSE transmission posed by the cross-contamination of ruminant feed by PM, as well as any inappropriate on-farm use. The provision to prohibit the use of SRM in fertilizers was intended to prevent the potential accidental or intentional misuse of fertilizers as feed.
SRM is collected, segregated, stained, and directed to a dedicated line/container. Collection, treatment, transport and disposal of SRM are done under a permitting systemFootnote 4. The SRM program is implemented, administered, monitored and enforced by the CFIA through inspection activities at dead stock collection sites, salvaging and rendering facilities, landfills, and other processing and disposal sites.
SRM collected for processing and disposal is predominantly sourced from slaughterhouses and on-farm bovine dead stock (Figure 1). Compliance verification programs of the measures in place to ensure the SRM ban is effective are detailed in Appendix 1.
Description for Figure 1
The image illustrates how Specified Risk Material (SRM) comes predominantly from slaughterhouses and on-farm bovine dead stock and is collected for disposal. SRM is not permitted to enter the human food and animal feed supply.1.4 Pathways for On-farm Exposure to the BSE Agent Associated with BSE Case #19
1.4.1 Residual Feed Contamination on Farm
The extensive UK experience with BSE led to the conclusion that the ingestion of contaminated feed remains the most likely source of BSE in infected animals born after the implementation of a feed banFootnote 5.
With two BSE cases diagnosed on the same birth farm the investigation of possible residual feed contamination on farm was conducted. The first case (BSE case #17) was born when the 1997 feed ban was in place, prior to enhancements to exclude SRM (Figure 2). While the second case (BSE case #19) was born 20 months after the enhanced feed ban was implemented, it is possible that small amounts of residual contaminated feed associated with the previous case could have remained on the farm Footnote 6. It is important to note that while the previous case (#17) most likely became infected in 2004, it did not arise as a BSE case until February 2010, almost a year after the birth of the case under consideration.
1.4.2 Maternal transmission
The report of the meeting of the OIE ad hoc group to review the BSE chapter in the OIE Terrestrial animal health code (2006) concluded that there was no evidence that vertical transmission of the BSE agent occurs. In this particular case, it has been determined that case #17 (commercial cow) is not the dam of case #19 (pure bred cow). The producer reported that the dam of case #19 was euthanized after an injury in February 2014, nearly five years after case #19 was born.
In this investigation, we noted that in 2009, case #17 calved on March 30, a few days after the birth of case #19 on March 25 (Figure 2). On this farm, as in most cow-calf herd practices, calving frequency was concentrated in time. The current literature5 considers horizontal transmission as a highly unlikely means of transmission of BSE and it was not further considered.
Description for Figure 2
The image illustrates the timeline of events regarding BSE cases 17 and 19 where both animals were born on the same farm.- BSE case #17 was detected in February 2010.
- The animal from case 17 was born in March 2004.
- The birth cohort for BSE case 17 was March 2003 – March 2005.
- The CFIA's Enhanced Feed Ban was implemented in 2007.
- BSE case 19 was confirmed February 2015.
- The animal from case 19 was born March 2009.
- The birth cohort for BSE case 19 was March 2008 – March 2010.
1.4.3 Environmental Contamination on Farm (carcass disposal)
Carcass disposal could be hypothesised to contribute to environmental contamination by the BSE agent. Western Canadian cow-calf farms are typically housed on large farmlands. Alberta Agriculture and Rural Development (now Alberta Agriculture and Forestry) legislation allows natural disposal of livestock mortalities under specific conditions (the animal is disposed of on the property owned by owner of the animal; the animal was not suspected of an infectious or reportable disease, nor was it euthanized with drugs or other chemical substances; the total weight of animals disposed of in one site does not exceed 1000kg; compliance with specific distances between sites, wells, livestock facilities, residences, roads and natural parks or areas; and natural disposal does not create a nuisance)Footnote 7.
On the birth farm, dead cattle were disposed of on farm. They were transported to the disposal location, situated on the fence line of a field that is not used for grazing. BSE case #17 was, as reported, incinerated at the Lethbridge CFIA laboratory.
Cows were normally on pasture from June to December. Any animals that died during that period were left on pasture. In the Canadian cow-calf industry, the annual death loss of cows is estimated to approximately 1%Footnote 8. In a farm this size, this could represent one or two cows dead on pasture annually. If one of these were infected, for successful transmission to occur, a susceptible young animal would need to ingest the BSE agent through scavenging the carcass or ingesting contaminated soil or plants. Considering that, unlike Chronic Wasting Disease and Scrapie, there is no evidence in the scientific literature concerning potential environmental pathways for the transmission of BSE, this potential route of infection was not considered further.
1.5 Pathways for Off-farm Exposure to the BSE Agent Associated with BSE Case #19
Considering that contaminated feed was the most likely source of infectivity in this investigation, pathways of infective material entering the feed system were examined. Given the fact that the enhanced feed ban was in place over a year prior to the birth of BSE case #19, the potential pathways for feed to become contaminated with infective material are limited, given the extremely low prevalence rate of BSE and the controls surrounding SRM (see Section 1.3; Figure 1; Appendix 1). However unlikely, if the BSE agent were to enter the feed chain, the potential source of contamination could involve two pathways: (1) incomplete removal of SRM from PM, or (2) cross contamination of feed (PM or non-PM) with SRM. Investigating potential cross-contamination with PM would be of interest in mills that use both PM and non-PM material. Investigating cross-contamination of feed with SRM involves examining the sources and movement of SRM from a live infected ruminant that:
1. Dies or is killed on farm:
Carcass (which contains SRM) may be disposed of on farm (see
Section 1.4.3), or may be picked up by deadstock for salvaging and
rendering.
2. Dies off farm:
- in transport,
- prior to slaughter, or
- at an assembly area
Carcass (which contains SRM) is sent for salvage and
rendering.
3. Is condemned at slaughter:
Carcass (which contains SRM) is sent for salvage and
rendering.
4. Is slaughtered:
The SRM is removed, treated under a dedicated
process and destroyed (or sent for destruction or disposal under license, at a
remote facility). Raw inedible material from the slaughter plant is forwarded to
the rendering plant.
Through any of these routes, at slaughter, salvage, rendering, or delivery of animal by-products to the mill, should controls fail, cross-contamination could occur. Therefore, the additional risks of feed being contaminated with SRM lie upstream from the feed mill, either at the rendering plant or the slaughterhouse. Many mechanisms are in place to ensure the SRM ban is effective and any potential cross contamination in the complex network of rendering, feed production, transport, storage and use are effectively eliminated (see Section 1.3; Figure 1; Appendix 1).
1.6 Pathways Investigated for BSE case #19
Epidemiological evidence across several countries suggest that a feed-borne source of BSE is the only substantiated route of infection for BSE, even after a feed ban is implemented to mitigate against the risk of feed being contaminated with the BSE agent. Many BSE affected countries that have implemented effective feed bans have detected limited numbers of cases Born After Reinforced (or enhanced or SRM) Ban. Such animals are referred to as BABs or BARBsFootnote 9. The majority are born within the first few years after the ban is introducedFootnote 10. In the UK, for example, two-thirds of BSE cases in cattle born after the original 1998 feed ban were born in the first few years after it was introducedFootnote 11.
Given the abovementioned on-farm and off-farm exposure pathways, two lines of enquiry were pursued to investigate possible sources of BSE infectivity in this case:
(1) On farm through residual or carryover of contaminated feed acquired prior to the enhanced feed ban; and
(2) Off farm through the acquisition of contaminated feed.
2. Feed Investigation
The feed investigation focused on feeds to which the case animal may have had access during its first year of life and on the manufacturing practices used to produce these feeds (March 2008 to March 2010).
2.1 Feeding Practice
A thorough and detailed feed investigation was conducted at the birth farm to identify all of the feed materials used, the suppliers and sources of these products. In addition, the feeding practices and storage and management practices were reviewed. The on-farm investigation focused on potential cross contamination incidents or incidental exposure to feeds that could have contained prohibited ruminant feed ingredients (primarily ruminant meat and bone meal) manufactured prior to July 2007.
On this farm, the calving season extended from February to June, with most calving occurring in March and April. During the first four months of life, the case animal would have nursed from its dam and had access to creep feed. In June, cow-calf pairs were moved to pastures where they were rotated through until December. All pastures were located in the same County as the birth farm, and there was no pasture sharing or mixing of animals with other farms. During this period, the case animal could have had access to hay, grain, pelleted cow ration, pelleted bull ration, free choice minerals and salt. The case animal would not have had access to milk replacer, because the only reported purchase of milk replacer was in February 2010, when the case animal was 11 months of age.
All feed products to which the BSE case was known to have had access were intended for feeding ruminants. Forages fed on the farm were grown and harvested on the farm or occasionally purchased from neighbors and transported with farm owned equipment. The producer did not mix feed on farm. Feed was purchased from the same suppliers over the years. During the period of interest, pelleted feed was delivered to the farm on a regular basis (every 3 to 9 months). The services of a feed consultant have been used since 2003. Ingredient processing of barley occurred with a portable roller; this equipment was shared with a neighboring farm. It was confirmed that this neighboring farm only used this equipment for rolling barley.
On-farm storage and usage practices of feed were such that all cattle on farm could have had access to any of the different feed types used on farm (creep, calf, cow or bull rations), all intended for feeding ruminants. Pet foods were stored in the dwelling house on site and livestock did not have access to these. Bin management and storage practices on farm could not eliminate the possibility that feed products produced prior to the enhanced feed ban may have remained (to some extent) on the farm post enhanced feed ban. However, there was no indication that feedstuff was stored for extended periods as part of the feeding practices on farm. The on-farm practices consisted of shoveling out a bin when it became empty prior to filling it again. The farmer reported this occurred approximately once a year.
Management practices on farm were similar to that of other cow-calf farms in Canada Given the nature of the feed used on farm (home grown forages, commercial feed/supplements manufactured specifically for cattle, no on farm mixing) there would have been no reason to consider the potential that feed might be contaminated. As discussed earlier, it is important to note that while the previous case (#17) born on this farm most likely became infected in 2004, it was not detected as a BSE case until February 2010, almost a year after case #19 was born and likely became infected. Considering the management practices and timelines of the two cases, it was not possible to rule out the potential for the carry-over of a small amount of residual contaminated feed on the farm.
2.2 Feed Sources
Investigations were conducted at all feed manufacturers to determine if they handled prohibited material and whether or not potential cross contamination of ruminant feed may have occurred. Specific attention was directed to ingredient sourcing, transportation, handling, manufacturing, storage and delivery/receiving practices.
Results of the investigation on the farm revealed that the case animal had potentially been exposed to various commercially prepared feeds during the period of interest (March 2008 to March 2010) (Table 1). None of the product formulations contained prohibited material.
| Commercial Feed Facilities (number of different feeds of interest) | Facility Profile Production Practices |
Feed Type | Rendering Facilities supplying
ingredients (Number and type of products) Table Note 1 |
Comments |
|---|---|---|---|---|
| A (4) | Facility handled Prohibited Material (PM) for feed preparations destined to non-ruminant species. Facility also handled non-PM rendered animal by-products. | Pelleted rations | J (1 PM and 1 non-PM) K (2, non-PM) L (1, non-PM) M (1 PM and 1 non-PM) N (1, non-PM) |
Review of available compliance inspection records during period of interest did not identify any situations that would have resulted in the contamination of non-PM sources with PM. |
| B (1) | Facility did not handle PM, but handled other rendered animal by-products. | Mineral supplement | J (1, non-PM) L (1, non-PM) N (1, non-PM) USA (1, imported, non-PM) |
Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of mineral feeds with PM. |
| C (2) | Facility did not handle PM, but handled other rendered animal by-products. | Mineral supplement | O (3, non-PM) USA (1, imported, non-PM) |
Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of mineral feeds with PM. |
| D (1) | Facility did not handle PM, but handled other rendered animal by-products. | Mineral supplement | L (1, non-PM) USA (1, imported, non-PM) |
Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of mineral feeds with PM. |
| E (2) | Feed manufactured and exported to Canada from a facility in USA | Lick tubs | Not investigated | Letter of guarantee provided by manufacturer stating that all products were free from non-prohibited ingredients in the manufacture of its products (to address BSE/restricted use of animal proteins as per US Regulations). |
| F (1) | Feed manufactured and exported to Canada from a facility in USA | Lick tubs | Not investigated | Letter of guarantee provided by manufacturer stating that all products were free from rendered mammalian protein (except gelatin coating on vitamins) provided by manufacturer, as well as, ingredient lists. |
| G (1) | Facilities did not handle PM or other rendered animal by-products. | Salt product | Not applicable | No animal by-products used in manufacture and only bulk product received is salt. Conveyances delivering salt to facility do not transport rendered products. |
| H (1) | Facility did not handle PM or other rendered animal by-products. | Salt product | Not applicable | |
| I (1) | Facility did not handle PM, but did handle other rendered animal by-products. | Milk replacer | P (1, non-PM) Q (1, non-PM) R (1, non-PM) S (1, non-PM) T (1, non-PM) USA (1 imported, non-PM) |
Feed was received when case animal was 11 months old, so exposure to this feed ruled out as it would not have been provided in feeding practices of case animal. |
Table Note
- Table note 1
-
See Table 2 for description of rendering
facilities
For each feed involved, information was gathered from facility management with regards to ingredients, the use of prohibited material in the facility, interviews with CFIA Inspectors and a review of inspection documents, as well as the compliance history of the facilities. Interviews and record reviews were also conducted to characterize transportation of incoming and finished products and to identify if these were transported by company owned or third party owned conveyances.
Based on the presence of PM and non-PM material, Facility A was considered to pose the most likely potential risk for an off-farm source of exposure to the BSE agent, if such an event had occurred. The suppliers of the mineral supplements (Facilities B, C & D) did not handle PM. The facilities did handle non-PM animal by-products, although none were included as ingredients in the mineral supplements. The potential for cross contamination with the BSE agent at Facilities B, C and D was considered negligible. Suppliers of lick tubs (Facilities E & F), located in the USA, were not investigated further. A letter from these suppliers indicated their products were free from rendered mammalian protein. Suppliers of salt products (Facilities G & H) were not considered further at risk because they do not handle PM or non-PM material. The facility supplying milk replacer (Facility I) was eliminated from further investigation with regards to the timing of purchased product and the potential for exposure of the animal. It was noted that facilities A and B were also identified as feed suppliers to the birth farm in the investigation of BSE case #17.
The supplier of the pelleted feeds (Facility A) to the birth farm produced feeds for ruminants and non-ruminant species. The non-ruminant feeds may include PM as an ingredient. Facilities that handle PM and manufacture ruminant rations are considered to be at a greater risk for potential cross contamination of feed. Facility A had documented procedures in place to prevent contamination of ruminant feeds with prohibited material in accordance with the requirements of the Feed Ban and legislative authorities. The commercial mill inspection completion rate for the area was 100% for the years 2008-2010. During the period of interest, Facility A had only one non-compliance recorded related to the feed ban (Health of Animals regulations). The non-compliance was a missing lot number on an invoice for feed containing PM and resulted in a corrective action.
A detailed review of individually manufactured feeds of interests at Facility A was conducted. It targeted 10 deliveries of the 4 different rations (creep, calf, cow or bull pellets), to which the case animal was known to be or was potentially exposed. Due to a flood at the facility, production records for 3 of these 10 feeds delivered to the farm, as well as any delivery records were not available. In reviewing the available mill records for all of the feeds delivered to the farm, there was no documentary evidence of potential cross contamination.
2.3 Rendered Animal By-product Sources
For BSE cases born prior to the implementation of the enhanced feed ban (EFB) (July 2007), the focus of the investigations was on commercial feed mills and subsequent transportation of feed to farms, and on farm feeding practices. At that time, SRM were rendered together with other prohibited materials (PM) to produce meat and bone meal (MBM) for feeding to non-ruminant species. Consequently, the feed investigation focussed on identifying possible opportunities for cross-contamination of feeds with PM that the case animal may have been exposed to. Now that SRMs are excluded from the entire animal feed chain, for cases born after the EFB, contamination of ruminant feed with PM is no longer the most likely potential pathway of exposure to the BSE agent.
To this end, as part of the feed investigation in this case, a more detailed investigation of sources of rendered animal by-products on the premises of the commercial feed facilities during the period of interest was also undertaken. As outlined in Appendix 1, the CFIA conducts regular compliance inspections at rendering plants at frequencies based on risks of transmitting BSE down the animal feed production and supply chain. Compliance inspection records for inspections conducted at the various suppliers of rendered animal by-products identified in Table 1 were reviewed. Instances of non-compliance at these facilities were assessed in relation to the likelihood of potential transmission of the BSE agent down the supply chain to a commercial feed facility and ultimately to the birth farm. The results of this analysis are provided in Table 2. In summary, the review of available compliance inspection records did not identify any situations that would have likely resulted in the contamination of PM rendered products with SRM or non-PM rendered products with PM or SRM.
| Rendering Facilities | Products manufactured | Comments |
|---|---|---|
| J | MBM (PM), blood meal, animal fat (tallow), animal/vegetable fat blend, SRM cracklings, feather meal | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| K | Porcine MBM, poultry meal, feather meal, blood meal, animal fat, yellow grease, poultry fat, porcine fat | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| L | Spray dried blood plasma | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| M | MBM (PM), animal fat | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| N | Fish meal, poultry meal | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| O | Porcine MBM, animal/vegetable fat blend | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| P | Blood plasma | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| Q | Animal/vegetable fat blend | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| R | Blood meal, porcine MBM | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| S | Fish meal | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
| T | Fish meal | Review of available compliance inspection records did not identify any situations that would have resulted in the contamination of non-PM rendered products with PM or SRM. |
3. Identifying and Tracing Cohort Animals
Cattle identified as birth cohorts to the case animal are being traced and destroyed in accordance with OIE requirements. This aims to eliminate animals potentially exposed to the same contaminated feed as the BSE case, although it is unlikely to provide any additional protection against the backdrop of the measures already in place, which include the ongoing feed ban and the exclusion of SRM at the time of slaughter from the human food supply.
The feed and birth cohorts were, in this case, indistinguishable because all animals from the birth cohort had access to the same feed as the case animal during the first year of life. The birth cohort was determined to be animals born after March 25, 2008 and before March 25, 2010. It consisted of 746 animals, based on an exact count of births recorded during the period of interest.
The trace-out investigation targeted the 746 animals of the birth cohort. The trace out investigation located 132 live animals, 99 of which were on the birth premises. All live animals, located on 14 different premises (including the birth farm), have been placed under quarantine. Of these, 22 live cohorts have been humanely destroyed. Disposal was in accordance with OIE recommendations and the CFIA's BSE Manual of Procedures. The remaining live cohorts have been permanently identified, their movements controlled and will be destroyed, or upon their death, their carcasses disposed of in accordance with the CFIA's BSE Manual of Procedures.
Disposition of the remaining 614 cohort animals are reported by category in Table 3. To dateFootnote 12, trace out activities have been finalised for 716 animals of the 746 in the cohort. Tracing of the remaining 30 animals is expected to be completed by the end of 2015.
The OIE no longer classifies the progeny of a BSE-positive cow as equivalent risk animals. However, tracing of the calves born to the infected dam within 24 months preceding the diagnosis of BSE (2013 and 2014 calves) was undertaken to satisfy specific country export requirements. Records indicated the 2013 calf died of scours soon after birth. The 2014 calf was born at the sampling site and is currently under quarantine.
| Trace Category | Description | Number of animals |
|---|---|---|
| Located | The animal of interest has been located and quarantined (destroyed). | 132 (22) |
| Confirmed dead | The animal has been traced to a location where it is known to have died. | 20 |
| Confirmed slaughtered | The animal has been traced to a slaughter plant, or a location known to assemble animals for slaughter only, including a terminal feedlot. | 303 |
| Exported | The animal has been traced to a location where it has been reported as exported. | 0 |
| Exported and slaughtered | The animal has been traced to a location where it has been reported as exported for immediate slaughter. The importing country has been notified. | 118 |
| Presumed dead | The animal has been traced to a location where it is believed to have died. The animal is not on the premises and there is no record or knowledge of it leaving the premises. There are no further avenues of investigation to pursue. Information on the purported disposition of the carcass is recorded if available. | 3 |
| Presumed slaughtered | The animal has been traced to a location where it is believed that the animal left only to slaughter or a terminal feedlot. There are no further avenues of investigation. | 130 |
| Untraceable | All avenues of tracing have been exhausted. The animal has not been located, or if located, has not been identified amongst non-trace animals, nor determined or believed to have died or been slaughtered. No further action is required. | 10 |
| Total closed traces Table Note 2 | 716 | |
Table Note
- Table Note 2
-
Tracing of remaining 30 animals is pending
4. Investigation Summary
Case #19 was a case of classical BSE in a Black Angus beef cow, 5 years and 10 months of age at time of diagnosis. It was born in March 2009, 20 months after the enhanced feed ban was implemented. A previous case of BSE was diagnosed on the same birth farm from an animal born in 2004.
As for other cases of classical BSE in Canada and in other countries, feed-borne infection is the most likely source of BSE in this case. BSE case #19 was born shortly after the enhanced feed ban was implemented, which may suggest residual feed contamination on-farm or off-farm as the source of infection. No significant events could be linked with this case but the potential for the carry-over of a small amount of residual contaminated feed could not be discounted. Considering the stringent safeguards implemented from 2007 to ensure that SRMs are excluded from the entire terrestrial and aquatic animal feed chains as well as fertilizer, together with the rigorous inspection oversight by the CFIA the contamination of both prohibited and non-prohibited materials with SRM at either a slaughter establishment or a rendering facility, would in all likelihood, be highly improbable. As a result, the carry-over of a small amount of residual contaminated feed associated with the earlier case (#17) on the same birth farm is the most plausible explanation for BSE case #19.
Trace-out of birth cohort animals is ongoing and expected to be completed for the end of 2015. Live cohorts traced are permanently identified, their movements controlled and upon death or destruction are disposed of in accordance with OIE requirements and the CFIA's BSE Manual of Procedures.
5. Impact of Current Findings
The results of Canada's ongoing surveillance program continue to confirm that BSE remains under effective control. Since it is widely recognised that cattle are most susceptible to becoming infected in their first year of life, an analysis of surveillance test results stratified by the year of birth (a birth cohort analysis) provides a surrogate measure of exposure to the BSE-agent in the cattle population in any given year. Even though Canada has recently had a BSE case born almost two years after enhancements were made to the feed ban in 2007 to exclude SRM from the entire terrestrial and aquatic animal feed chains, the updated results from a birth cohort analysis incorporating this case confirm that the overall risk profile has not changedFootnote 13. The impact of this case on the prevalence estimates for the 2009 and subsequent birth cohorts is inconsequential. They remain extremely low.
Appendix 1. Enhanced Feed Ban Compliance Inspection Programs
Abattoir:
In federally registered abattoirs inspections are undertaken on a daily basis by an on-site CFIA inspector. This includes segregation in the inedible area, staining, the dedication and labelling of containers and the verification that transporters picking up the SRM have a valid and current CFIA permit authorizing this activity. For non-federally registered abattoirs, inspections are carried out by on-site provincial inspectors, or quarterly by CFIA or provincial inspectors.
Transporters of SRM:
Transportation of SRM, including bovine deadstock from which SRM has not been removed, and SRM that has been subjected to intermediate processing (such as rendering or composting), is controlled through the issuance of permits from the CFIA. Permits are issued annually for commercial operations and permitted site is subject to quarterly inspections.
Rendering facilities:
During the period of interest (2008-2010), the inspection frequency of inedible rendering plants in Canada by CFIA was as follows:
| Facility Risk Profile | 2008-09 | 2009-10 |
|---|---|---|
| Process SRM, PM and/or non-PM | Full time (24 hour daily presence) |
Full time Table Note 3 (24 hour daily presence) |
| Process SRM only (stand-alone facility) | 4 inspections/ year | 4 inspections/ year |
| Process PM and non-PM | 4 inspections/ year | 4 inspections/ year |
| Process PM only | 2 inspections/ year | 2 inspections/ year |
| Process non-PM only | 2 inspections/ year | 1 inspection/ year |
Table Note
- Table Note 3
-
During 2009-10. Inspection frequency at these
facilities, based on an excellent level of ongoing compliance, transitioned to 4
inspections/ year
All inedible rendering plants operating in Canada require a permit to operate, which is issued on an annual basis by the CFIA. Prior to the issuance of a permit to operate, each rendering plant must be fully inspected to confirm that they are operating in accordance with the conditions of their permit, including compliance with the Health of Animals Regulations and Feeds Regulations. Inspections verify that written procedures and records of the facility meet the regulatory requirements related to preventing cross-contamination of non-prohibited materials with PM or SRM during the transportation and handling (e.g. delivery vehicles, containers, tools and other equipment used to collect, remove and transport) of raw material or finished rendered product. If non-compliance is identified, mechanisms are in place to control and mitigate risks in terms of product control and systemic corrections by the facility.
Confinement and Destruction of SRM:
A CFIA permit is required for the confinement and destruction of deadstock cattle containing SRM; meat and bone meal (MBM) made from deadstock cattle or SRM; and compost made from deadstock cattle or SRM and permitted site is subject to quarterly inspections.
Commercial Feed Mills:
Commercial Feed Mill inspections are conducted at commercial feed manufacturing establishments to:
- confirm that feeds are being manufactured and used in compliance with the Feeds Regulations and Health of Animal Regulations, for the purpose of reducing the potential for feed-related problems affecting animal and/or human health or the environment; and
- confirm that feeds are being imported and sold in compliance with the Feeds Act and Regulations and the Health of Animal Act and Regulations.
The purpose of this program is to verify that commercial feed mills:
- manufacture safe, compliant, correctly labelled feed; and
- follow procedures relating to feed manufacturing, labelling and record keeping, to ensure that the integrity of the feed is maintained and the complete distribution of any feed is identified.
The risk categorization for commercial feed mills considers the food safety and animal health risks associated with the spread of Transmissible Spongiform Encephalopathies (TSEs) via feeds and the use of medications in feeds.
The following risk categories have been identified for commercial feed mills:
- High Risk –TSE
- Facilities that manufacture feeds containing prohibited material and manufacture ruminant feeds
- Low Risk-TSE
- Facilities that do not have both risk factors for TSE
- High Risk – Medications
- Low Risk - Medications
These risk factors are used to determine inspection task frequencies for feed manufacturing facilities. The table below identifies the risk factors and the corresponding number of inspection tasks to be assessed at commercial feed mills based on the risk categories.
During the period of interest (2008-2010), the inspection frequency of commercial feed mills was as follows:
| Risk Category | Risk Factors | 2008-09 | 2009-10 |
|---|---|---|---|
| 1 | High Risk TSE and High Risk Medications | 4 inspections/ year | 3 inspections/ year |
| 2 | High Risk TSE and Low Risk Medications | 2 inspections/ year | 2 inspections/ year |
| 3 | Low Risk TSE and High Risk Medications | 2 inspections/ year | 2 inspections/ year |
| 4 | Low Risk TSE and Low Risk Medications | 1 inspection/ year | 1 inspection/ year |