There remains the possibility that milk produced by dairy cattle exposed to the BSE agent contains some infectivity itself and therefore poses a risk to the human population and to successive generations of cattle. The evidence for this possibility is derived mainly from interpretations of epidemiological data as no direct experimental data have been generated by appropriate methodologies to determine the presence of the agent in milk. Milk is the only product derived from BSE-susceptible animals over thirty months of age which is available for public consumption. Therefore an analysis is required of the risk, based on analytical data, for effective policy control measures to be considered. The results will also provide direct experimental evidence for the involvement of milk in any maternal transfer of the disease and thus for DEFRA policy for the control of BSE itself.
This project seeks to determine whether PrPbse is present in milk collected from cattle experimentally infected with BSE. Milk samples are to be collected at various stages in the development of the disease and then two approaches are to be used to analyse if PrPbse is present in these samples. These are:
- The application of current PrPbse screening tests to the cellular/milk solids fraction.
- The development of immunoaffinity and ligand-affinity prion isolation procedures for application to the archived whole milk and cellular fractions.