The Washington Department of Fish and Wildlife's Chronic Wasting Disease Program 1996-2003

From 1996-2000, a total of approximately 80 brainstems from deer and elk throughout Washington were collected by the Department of Fish and Wildlife (WDFW) and tested for evidence of chronic wasting disease (CWD) by immunohistochemistry. From 2001-2003, 2,149 brainstems from deer and 336 brainstems from elk where collected and similarly tested. The majority of the samples were collected during established hunting seasons from hunter-harvested animals and from road kills. Approximately 2-3 samples per year were collected from animals demonstrating clinical signs compatible with CWD. Of the 2,287 usable samples collected, all tested negative for CWD. From 2001-2003, an adequate number of samples was collected from 10/36 (28%) of WDFW deer population management unit (PMUs) to allow us to conclude with 95% confidence that CWD would have been detected if it were present in the population at a prevalence of 5%; and from 3/36 (8%) of the deer PMUs to allow us to conclude that it would have been detected if present at a prevalence of 1%. An adequate number of samples was collected from 2/10 (20%) Washington elk herds to allow us to conclude with >95% confidence that CWD would have been detected if it were present at a prevalence of 5%.