EFSA recommends continuation of EU sheep breeding programme to reduce risk of scrapie and BSE

The European Commission (EC) has put in place since 2001 a comprehensive programme[1] to protect both consumers and animals from risks related to TSE/BSE (Bovine Spongiform Encephalopathy). Since its establishment in 2002, EFSA has provided scientific advice to the European Commission to support its TSE-related measures[2]. EFSA has now been asked to evaluate and advise on an existing programme on breeding of sheep for resistance to TSEs which is in force since April 2005. This programme aims at breeding sheep, resistant to TSEs, by eliminating certain genes which are more prone to TSE infection and encouraging those which resist more robustly these diseases. The EU breeding programme for TSE resistance in sheep is an important measure both for animal and human health to reduce risks from TSEs in sheep, including BSE should it be found in the sheep population.

In its Opinion, EFSA’s BIOHAZ Panel confirmed that the breeding programme increases the robustness of sheep populations against the currently known TSEs and therefore contributes to both improved animal health and consumer protection. No evidence was found that the current breeding programme has had adverse effects to date and the Panel therefore recommends its continuation with some minor amendments. For BSE and classical scrapie, the sheep breeding programme helps in controlling the animal health problem and reduces significantly any possible human exposure to these diseases. For atypical scrapie, the current breeding programme is likely to reduce the animal health problem and human exposure; however, the timescale for the reduction of risk may be longer than for other TSEs. The Panel concluded that the current breeding programme neither encourages any known TSEs (such as atypical scrapie) or other diseases nor does it affect the vitality and performance of the animals. The Opinion takes into account human exposure and animal health aspects of BSE, classical scrapie and atypical scrapie and evaluates the impact that the breeding programme has on these.

The Panel noted that in order for the programme to be effective, it would not be necessary for the whole sheep population to be bred for resistance, that is to say, not all sheep need to carry the resistant genes. It also recommended preserving samples of semen and embryos from sheep carrying the gene types which have been out-bred. The Panel affirmed that preservation of the diversity of the gene pool is important in order to protect sheep should any unknown adverse effects or new diseases be detected in the future.

In addition, EFSA’s BIOHAZ Panel:

• called for more research to be carried out on atypical scrapie to assess any potential human or animal health risks, whilst noting that this disease is not presently considered as transmissible to humans;
• confirmed that it considers unlikely that sheep bred for TSE resistance could infect other sheep with BSE through the placenta and body fluids (i.e. by contaminating pasture and spreading the disease to other sheep);
• recommended that a Quantitative Risk Assessment of BSE risk in the EU sheep population be carried out on a regular basis and noted that the BIOHAZ Panel would provide such an assessment over the coming months.

EFSA will continue to liaise closely and co-ordinate its TSE-related risk assessment activities with Member States and particularly with those countries, such as France and the UK, which are currently carrying out work in this area.

• Opinion of the Scientific Panel on biological hazards (BIOHAZ) on the Breeding programme for TSE resistance in sheep