2006 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and the University of Washington. Additional details of research can be found in the report for the parent project 5348-32000-021-00D BSE and other TSES Ruminant Herbivores: Diagnosis, Transmission and Genetics. Our goals are to develop transgenic CWD mice for testing the relationship between prion genetics and CWD susceptibility to infection and disease. Secondly we are collaboratively studying cross species transmission. We've established two founder female mice that contain a mule deer prion clone derived from a Bacterial Artificial Chromosome. Founders have been used to generate a colony of CWD transgenic mice, backcrossed to a line lacking the endogenous mouse prion gene. Infectivity challenge experiments have commenced, and mice will be monitored for signs consistent with TSE. Secondly, as part of the agreement we are testing the hypothesis that Elk CWD is transmissible to mink. This experiment serves to determine the transmissibility between these two natural occurring TSEs and will establish a model for anti-prion vaccine testing. Preliminary findings of the mink challenge experiment will be reported within the next fiscal year.