REPORT ON ACTIONS TAKEN BY CANADA IN RESPONSE TO THE CONFIRMATION OF AN INDIGENOUS CASE OF BSE

The team consisting of Prof. U. Kihm (Switzerland), Prof. W. Hueston (USA) and Dr. D. Heim (Switzerland) convened in Ottawa on 7-9 June 2003. Additional input by phone and e-mail was available from Dr. S. MacDiarmid in New Zealand.

The team was provided an overview of the epidemiological investigation, the actions taken to date, and the scope of options and measures being considered to adjust domestic policies to address the new reality that exists in Canada and within the broader North American context.

The team wishes to clearly acknowledge the openness, full disclosure and access to personnel provided by the Canadian authorities to our team, the international community and the public. The approach to sharing of information and communication demonstrated by Canada is a model to be emulated.

Investigation to date

The team is impressed with the comprehensive scope, level of analysis and thoroughness of the investigation to date. In a very short time Canadian experts have collected and assessed a level of information that exceeds the investigations done in most other BSE-affected countries. This serves as a testament to the competence, capacity and dedication of effort of Canadian officials.

The investigation has looked at both the circumstances surrounding the index case of BSE and the macro-epidemiological risk factors which have contributed to the expression and detection of the first indigenous case in North America.

It is important to acknowledge that measures previously in place achieved their designed outcome as demonstrated by the identification of the positive animal in a manner which precluded its entry into the human food chain. Furthermore, the various risk management measures implemented by Canada over a number of years have reduced the risks of spread and amplification of the disease.

The team applauds the proactive examination of industry characteristics (rendering industry, feed formulation, feeding and husbandry practices on farm and the surveillance activities) that is essential to a full understanding of the complex interrelationships of factors associated with the disease. The Canadian regulators, veterinary profession and livestock industries have learned in a demonstrable way from the experiences of other countries which have been affected by BSE, and have applied that knowledge beneficially.

Actions Arising From the Investigation

The Canadian experts have established epidemiological evidence that supports the probability that the expression of BSE in the case animal was associated with exposure to infective material through the feeding system at some point early in the life of the animal.

Prior to the implementation of the feed ban in 1997, opportunities existed for animals in the source herd to have been legally fed rations containing ruminant MBM. It cannot be determined whether the contaminated MBM was of imported or domestic origin. Neither can past exposure of other cattle to contaminated feed be discounted. The possibility that products were derived from the positive cow, and the possibility that other infected cattle in the late stages of incubation are present in Canadian herds, lead to the conclusion that the adoption of additional measures to reduce or eliminate future exposure are warranted.

It can reasonably be assumed based on the collective experience of other countries that adjustments must be undertaken promptly to address the possibility that other animals may have been exposed and are incubating the disease.

A significant factor which affected the scope of the investigation, and the extensive culling of animals which resulted, was the limitation imposed by the lack of a mandatory animal identification program in existence prior to 2001. This necessitated the extended application of all available scientific methods and investigative tools in an effort to compensate for the absence of a traceability system dating back seven years.

Given the quality and extent of information gathered to date, the team considers it appropriate for the active investigation and the culling activities to be concluded and the focus redirected to short and mid term policy adjustments which would serve to address the changed North American dynamic.

Further investigation of feed and exposure cohorts, along with the disposition of the MBM created from the index cow, are unlikely to yield further insights nor contribute in a meaningful way to protection of public or animal health and should be discontinued.

The investigations have clearly identified the potential for past exposure and clearly established the need to address the risk that BSE is present in the Canadian herd and beyond.

The review team recognised that the initial response followed established veterinary practice for disease control for contagious diseases. However, in light of the consensus that BSE is not a contagious disease, this approach should be reconsidered, and measures to prevent exposure through contaminated feed should be implemented and controlled on a national level.

Future policy actions

Policy actions being considered by Canada must achieve the following objectives:

• reduce public health risk for consumer protection
• further limit recycling and amplification of the agent
• establish a benchmark for the effectiveness of measures through surveillance
• prevent any inadvertent introduction of BSE from abroad in the future
• contribute to the prevention of the spread of the epidemic worldwide

To achieve these objectives, a system of complementary barriers, and implementation of all measures on the national level, is necessary.

These goals cannot be successfully achieved by government alone; their implementation requires a shared commitment and action on the part of national and provincial governments, producers, consumers, industry, and veterinary professionals. Extensive national coordination and cooperation is imperative.

The team recommends that the following measures are the ones which should be given highest priority for adoption. Other measures may be adopted at a later time, and a periodic re-assessment of the measures is advisable. Depending on the evolution of of the BSE situation in Canada, and North America as a whole, modification of some of these measures may be appropriate.

Prohibition of Specified Risk Materials (SRM)

Implementation of an SRM ban is the most critical and valuable central measure for public health protection and food safety and is fully endorsed by the review team. An SRM ban would also reduce the risk of infectivity in animal feed.

A plan for the safe removal, collection and destruction of the SRM should be immediately developed. Measures to ensure that SRM are not included in human food and animal feed should be implemented, enforced and audited for compliance.

The list of material considered as SRM and the age of animals included must be based on science to ensure that potentially infected material does not enter the feed and food chains. The list of SRM must be based on knowledge derived from the extensive studies on cattle, which have demonstrated that BSE infectivity may be present in brain, spinal cord, trigeminal ganglia, dorsal root ganglia, terminal ileum, eyes, and tonsils. The age of the cattle included in the ban should be determined by science and practical aspects of implementation must also be considered. The timely and full national implementation of this measure should be a priority. Its adoption will greatly influence the relative scope of other measures.

Additional measures to avoid contamination with SRM at slaughter and during processing should be considered (e.g. stunning techniques).

Advanced Meat Recovery/Mechanically Recovered Meat

In advanced Meat Recovery (AMR) procedures and Mechanically Recovered Meat (MRM) systems must be implemented to exclude raw materials containing potentially infectious tissues (skull, vertebral column).

Control of SRM, AMR and MRM ban

To insure that no central nervous tissue is included in food, especially that derived from AMR and MRM, sampling and testing programs should be adopted. These programs should be implemented on a test-and-hold basis and should include destruction of any contaminated products to exclude its use in the human or animal food chain.

Surveillance

Adjustments to surveillance approaches are warranted in the new environment in order to determine the current prevalence and to judge the effectiveness of measures implemented over time.

The review team supports the proposal for an increased targeted surveillance program to be implemented at the national level. This program should focus on the highest risk populations of adult fallen stock and dead stock, cattle demonstrating clinical signs compatible with BSE and downer cattle. Ideally all cattle of these high risk populations should be tested. Additional measures are recommended to assure that high risk cattle are not entering the food chain by other routes.

Furthermore, in accordance with the investigations carried out by the Canadian experts, specific geographical and temporal risk groups within the national cattle population have been identified. Targeted surveillance activities to encompass this cohort of animals are also encouraged.

Feed Restrictions

The review team strongly endorses the exclusion of Specified Risk Materials from the feed chain as an effective means to reduce infectivity in meat and bone meal (MBM). The difficulty in distinguishing ruminant derived MBM from other mammalian and poultry derived MBM must be considered. Inclusion of any ruminant-derived MBM in ruminant feed rations should be avoided and opportunities for possible cross contamination eliminated. Whether this can be guaranteed by introduction of a mammalian MBM ban to ruminants or other specific measures has to be evaluated.

For risk reduction at the farm level where multiple species are raised, a system should be implemented that avoids possible cross feeding of rations containing ruminant MBM among species. Such an on-farm system would have to be closely audited for compliance and the resource implications of adequate monitoring may make prohibition a more practicable measure.

Identification Preservation and Traceability Systems

The current investigation reinforces the need for continuous investment, improvement and extension of the cattle identification system, initiated 3 years ago.

Import policies

Import policies should be subject to ongoing review to address the continued global risks and to ensure that products entering the country fully meet the same stringent standards for health protection prescribed domestically. Import controls must be rigorous enough to avoid introducing additional infectivity into the animal feed system using additional controls both in the country of origin and post entry (e.g. testing of fishmeal and poultry meal for possible contamination or inclusion of mammalian MBM).

Export

Export policy and regulations should be re-assessed to provide all reasonable assurances that BSE is not further spread.

Education

Disease awareness among producers, veterinarians, and personnel from the feed and slaughter industries and other related industries is critical for effective implementation and compliance with import requirements, feed restrictions, SRM control and surveillance as well as for the protection of animal feeds and human foods. Universities have a special obligation to emphasize key information on BSE diagnosis, prevention and control.

Risk communication

The Canadian authorities should continue their excellent practice of involving concerned parties in the identification of risk factors, assessment of risk and discussion of the most appropriate risk management approaches. Equally important is continuing the close collaboration with public health officials to keep risks to public health in perspective. Efforts to ensure a broad consumer understanding of the nature of the disease and the safety of consuming muscle meat is required to address misconceptions that have been associated with the disease in the past.

Future case investigations

The first BSE-case in Canada was intensively investigated and extensive information gathered. Based on experience in other BSE-affected countries, future investigations can be conducted on a more restricted basis because there is limited additional information to be gained.

Culling policy

Based on the fact that BSE is not a contagious disease, culling decisions can be postponed until after the epidemiological investigation has been finalised, as long as entry of the animals into the food chain is temporarily prohibited.

A culling policy consistent with the following recommendations derived from the recently adopted BSE chapter of the OIE International Animal Health Code is recommended. This policy includes culling of:

• progeny (of affected females) born within 2 years prior to, and after clinical onset of the disease, if still alive, and
• all cattle which during their first year of life were reared with the affected animal during the first year of its life and which investigation showed consumed the same potentially contaminated feed during that period, or
• where the results of an investigation are inconclusive, all cattle born in the same herd as, and within 12 months of the birth of the affected animal.

Enforcement (control of implementation)

All measures implemented through the revised policies should have clear and well understood performance indicators and should be supported with intensive compliance and verification activities. Such compliance activities should extend beyond document verification and include operational spot checks and laboratory analysis where applicable. The provincial controls for implementation should be supervised by a central authority in order to assure a harmonized approach.

Equally important is that all measures must be truly national in scope and implementation must be to a common standard across all levels of jurisdiction.

Infrastructure

A good veterinary infrastructure including diagnostic laboratories is essential to support disease investigations, surveillance systems, epidemiological analyses and policy considerations. The response to the case of BSE in Canada required redirection of a significant portion of their national capability. Infrastructure enhancements will be necessary to sustain the BSE response as well as maintain other national animal health priorities.

Bern, Switzerland
26 June 2003