EFSA TSE/BSE risk assessments and uncertainties, including GBR and MBM

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Since Bovine Spongiform Encephalopathy (BSE) was reported for the first time in 1986 in the UK , the European Union (EU) has developed a comprehensive set of risk reducing measures on transmissible spongiform encephalopathies (TSEs) in order to protect human health from BSE and to control and eventually eradicate TSEs in animals. That legislation has continuously been reviewed in the light of new scientific evidence, the evolution of the TSE situation and the practical implementation in the field.

The key piece of legislation to protect human and animal health from the risk of BSE and other TSEs was adopted on 22 May 2001 . This Regulation (EC) No 999/2001 of the European Parliament and of the Council (EU, 2001) lays down rules for the prevention, control and eradication of certain TSEs.

One of the most effective risk reducing measures consisted of a total EU wide ban on the use of processed animal protein in feeds for any animal farmed for the production of food, with some exceptions ( e.g. use of fishmeal in non-ruminants). This measure was introduced in January 2001. In the context of the declining BSE epidemic in cattle and following the strategic document “The TSE Roadmap”, risk assessments are carried out by EFSA on a large variety of TSE related aspects of risk to human and animal health. The general approach including two examples is given in this context: The Risk Analysis and Risk Assessment frameworks; Scientific Uncertainties in Risk Assessment; Uncertainties in BSE-TSE Risk Assessments with respect to Hazard Identification, Hazard characterisation, Exposure assessment and Risk characterisation ; Examples: The EFSA Geographical BSE Risk (GBR) assessment and Other MBM (Meat and Bone Meal) related uncertainties.

The GBR is an indicator of the likelihood of the presence of one or more bovines being infected with BSE, pre-clinically as well as clinically, at a given point in time, in a country. The major components of this model are the External Challenge and the Stability of the system, including the basic assumption that BSE was only propagated through the recycling of contaminated animal tissues into bovine feed, but a number of uncertainties on different aspects of BSE remain.

Specifically with respect to MBM, some major uncertainties are highlighted e.g. with respect to the attack rate, the field CoID 50 , cumulative dose effect below CoID 50 , transmission under 0,1% MBM in feed for ruminants, definition of a tolerance level using LOQ (level of quantification), definition of LOD (level of detection) using microscopy or NIR, and identification of the species composition with immunoassay or PCR.

E. Vanopdenbosch