2008 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research project is to describe the dissemination pattern of abnormal prion protein in the tissues of captive and free ranging Rocky Mountain elk. 1b.Approach (from AD-416) Describe the distribution and characteristics of abnormal prion protein in the neural and extraneural tissues of captive and free ranging elk with clinical and preclinical chronic wasting disease. Experimental Design: The CWD status of Rocky Mountain elk will be determined by live animal biopsy of rectal mucosal lymphoid tissues from Rocky Mountain elk. Immunohistochemistry of the biopsy sample is performed using methods developed by the cooperator and ARS. Elk with positive test results are euthanized and tissues collected from neural and extraneural tissues. A panel of 25 tissues per animal is examined with a battery of antibody based and histologic methods for evidence of abnormal prion protein accumulation and evidence of spongiform encephalopathy. ARS will analyze the open reading frame of the prion protein in each animal. Documents SCA with Colorado State University. 3.Progress Report Dissemination of abnormal prion protein in the neural and extraneural tissues of wild Rocky Mountain elk: Project Number 5348-32000-026-10S. This report serves to document research conducted under a specific cooperative agreement between ARS and Colorado State University. Additional details of research can be found in the report for the parent project 5348-32000-026-00D Transmissible Spongiform Encephalopathies: the role of genetics, strain variation, and environmental contamination in disease control. The purpose of this new SCA is to describe the distribution and characteristics of abnormal prion protein in the neural and extraneural tissues of captive and free ranging elk with clinical and preclinical chronic wasting disease in order to improve the sensitivity of antemortem tests for chronic wasting disease in deer and elk. 138 Rocky Mountain elk have been tested for CWD using a candidate tissue biopsy assay. Elk will be monitored for 2 years for development of CWD. The project is monitored by the ADODR by frequent telephone conferences, electronic exchange of data, and personnel visits to the research site in Colorado.