- To demonstrate the potential to identify animals pre-symptomatic for BSE and Scrapie and humans pre-symptomatic for CJD with a simple practical specific and sensitive immuno-diagnostic test done in ml quantities of animal and human body fluids.
- To demonstrate that information obtained with the test can be used to identify animals infected with BSE and scrapie among those without obvious clinical symptoms of the diseases and exclude them from entering the food chain and to ensure that blood and blood products given to humans are not contaminated with a CJD associated agent.
- To demonstrate that the precautionary wasteful destruction of hundreds of thousands of uninfected cattle can be prevented.
Using proprietary technology called DGDPS, coding sequences for three potentially pathogenic proteins, "BSAS", "SCRAPAS" and "CJAS" were discovered within the genes encoding the major prion protein of cows, sheep and humans respectively. A similar protein located within the mouse prion gene did not have pathogenic features. A highly specific and sensitive ELISA test based on purified antibodies prepared against chemically synthesized epitopes from BSAS, SCRAPAS and CJAS, showed that BSAS and SCRAPAS were present in blood and urine in all cattle and sheep with clinical symptoms of BSE and scrapie. The test also showed that the proteins were present in about 30 % of clinically normal animals in herds, or regions, where BSE or scrapie was present; the proteins were not present in animals which came from herds which had no history of BSE or scrapie or from herds from countries which had been completely free of BSE or scrapie. These findings provide strong evidence that the test detects pre-symptomatic and latent BSE and scrapie in animals that are clinically negative according to present criteria. The latter is the basis for using the test to screen entire herds and flocks for BSE and scrapie which should lead to elimination of infective animals from among them. Total screening of herds and flocks can lead to the eradication of these diseases in the time that it takes to test all animals in areas that are known to harbour the disease. The same argument applies to wide scale testing of human blood and blood products used in clinical applications to eliminate the passage of CJD to humans from infected blood. The results of tests and screening of animals and blood will be presented in detail, in organized workshops, to governmental ministries, health professionals, regulatory agencies, consumer groups, farmers and shepherds so that full consideration can be given to introducing mandatory testing before animals are slaughtered or their products are allowed to enter the food chain.
Funding SchemeCSC - Cost-sharing contracts
CB5 9PB Waterbeach Cambridge