§ The Countess of Marasked Her Majesty's Government:
How many strains of scrapie have been identified in the UK, and, if more than one strain has been identified, whether there is a regional pattern to the incidence of different strains.
Lord LucasIt is difficult to quantify the exact number of strains identified in Great Britain as they will not all have been characterised contemporaneously in the same mouse models, but an approximate answer would be 20. This may however be an over-estimate because of the tendency for scrapie agents to adapt to the experimental host species, giving rise to new strains in the laboratory. There have been too few field isolations and characterisations to be able to associate specific strains with geographical areas.