Virology
Interbreed cross genotype transmission studies of ovine
scrapie
Principal Contact: Dr Francesca Chiannini
Defra funded project in collaboration with VLA
It is still uncertain as to whether different strains of scrapie truly exist naturally in sheep and if they do, whether they affect all PrP genotypes equally. Two types of scrapie have been previously described in experimental scrapie studies of susceptible Cheviot sheep inoculated with SSBP1: A group strains which affect sheep with at least one VRQ PrP gene allele, and C group strains which affect sheep of QQ171 genotype regardless of the presence of other genes. In Suffolk sheep scrapie primarily affects ARQ/ARQ animals as the VRQ allele is extremely rare. It is unclear whether this means that Suffolk sheep are affected only by C group scrapie or whether the rarity of the VRQ gene reflects a breed difference which 'accidentally' controls scrapie susceptibility. This project aims to investigate if scrapie from natural cases in Suffolk and Cheviot sheep is capable of being transmitted to each other, and if so, what similarities and differences exist in the clinical signs, the patterns of vacuolation in neuronal tissue and distribution PrPd, a disease marker associated with scrapie infection.
The results from this experiment will be of great importance to the National Scrapie Plan and the possible eradication of scrapie from the UK flock.