Can BSE infect sheep?
It is not known if BSE may spread or be maintained within the sheep population but, if it were present, it may be masked by a similar brain disease of sheep called scrapie, which has no known link with human disease. vCJD in humans is strongly linked with BSE in cattle and thought to have arisen through the consumption of meat products derived from eating infected cattle before measures to protect human health were implemented.
Sheep have been experimentally infected with BSE and results indicate that if BSE were to be discovered naturally occurring in sheep, the spread of BSE infectivity would be throughout the carcase and as a result SRM measures in isolation may not be a cost effective or a suitably robust means to protect human health. The whole carcase of potentially infected sheep would have to be destroyed. However sheep, unlike cattle, have a range of genetic types known as Prion Protein (PrP) genotypes which make them either more naturally resistant or susceptible to scrapie and theoretically BSE. This forms the basis of one of the key risk reduction strategies already in place - the Northern Ireland Scrapie Plan.
The present position is that BSE has never been found to occur naturally in the UK sheep population. In addition, ongoing research and TSE surveillance has not found confirmatory evidence of BSE in sheep. Sheep that are suspected of having any spongiform encephalophy, such as scrapie, do not enter the human food chain - they are compulsorily slaughtered with compensation paid to the owner. In addition, and purely on a precautionary basis, tissues designated as specified risk material (SRM) are removed from all human consumption sheep at the abattoir and destroyed.
The European Union requires that Member States draw up their own contingency plans with the measures that would be introduced if BSE were found naturally occurring in sheep. The purpose of the contingency plan is to protect public health, to safeguard animal welfare and manage the impact on the sheep sector and the environment. In June 2004, Government published an overarching UK contingency plan as part of the consultation process with stakeholders. Following receipt of the consultation responses, it was evident that the plan would need to be more proportionate and graduated in line with the level of risk. As a result UK Agriculture Departments, in conjunction with Animal Health in GB, the Department of Health, the Food Standards Agency and the Veterinary Laboratories Agency, devised a new ‘High Level UK Contingency Plan for the Emergence of Naturally Occurring BSE (or other Zoonotic TSEs) in Sheep or Goats’. This High Level UK Plan can be seen on the Defra website.
The high level contingency plan has been developed against the background of the very low and diminishing likelihood that BSE will be found occurring naturally in sheep or goats in the UK. The plan will be kept under review in light of developments in scientific understanding, Government and European Commission policy and the capability of the UK to put systems in place to manage the risk should BSE be found in sheep or goats.
While the revised plan provides details on the circumstances for activation and possible measures in the UK, it is, likely that if BSE were found to be naturally occurring in sheep in any Member State, the European Commission would introduce separate measures to deal with this on an EU-wide basis.
For further information on BSE in Sheep contingency planning, please contact us