2008 Annual Report 1a.Objectives (from AD-416) The overall objective of this cooperative project is to evaluate PrP**D tissue distribution and migration in cattle orally infected with BSE of British origin. To achieve this objective, the following specific approaches will be conducted: (1) the protein misfolding cyclic amplification (PMCA) assay will be used on blinded replicate aliquots of tissue from animals in the BSE study to independently confirm whether PrP**D can be detected in the tissue samples. The Cooperator will function as lead investigator and ARS will confirm test results for the presence or absence of PrP**D in any given sample. (2) The Cooperator will analyze the proteome in tissue samples by two dimensional SDS PAGE. (3) NADC will evaluate microscopic pathology and visual function of the retina of available animals and tissues to assess PrP**D accumulation and visual function effects. 1b.Approach (from AD-416) The German BSE oral pathogenesis study involves 56 beef cattle orally dosed with BSE containing brain tissue obtained from British cattle. The animal study is managed by the cooperator and various tissues are collected at prescribed times and at necropsy. These tissues will enable the cooperating parties to perform independent confirmation on the presence or absence of PrP**D for verification of PrP**D distribution in tissues. In addition, retinal samples will be analyzed to assess the extent of retinal pathology in infected cattle and visual system function in available remaining live cattle will be tested using electroretinography. 3.Progress Report The overall objective of this cooperative project is to evaluate PrP**d tissue distribution and migration in cattle orally infected with Bovine spongiform encephalopathy (BSE) of British origin. The live-animal phase of this work was completed this year. Samples from this experiment will be brought to the USDA, ARS, National Animal Disease Center for further characterization in the upcoming year. Methods used for monitoring included phone contact, e-mail, and site visits. This project addresses NP 103, component 8.