11 PERCENT SUB-CLINICAL CWD INFECTION RATE IN SAMPLE POPULATION ELK ROCKY MOUNTAIN NATIONAL PARK
Posted Jun 24 2008 5:07pm
Preliminary Results for Research on Live Chronic Wasting Disease Test for Elk in Rocky Mountain National Park
Date: April 10, 2008 Contact: Kyle Patterson, 970-586-1363
In January, research began in Rocky Mountain National Park to evaluate procedures for testing live elk for chronic wasting disease (CWD). This is the first time free ranging elk have been tested for CWD using this live procedure. This study is being done at the park to take advantage of the implementation of the recently announced Rocky Mountain National Park Elk and Vegetation Management Plan.
Elk were captured from early January through mid March. The majority of captures took place in Moraine Park and near Beaver Meadows Visitor Center. Out of 136 female elk captured, (there were 117 usable biopsies), 13 tested CWD positive and were removed. Complete necropsies were performed and confirmed those results. Based on those results there was an 11 percent estimated CWD prevalence rate in this sample population. At the time of capture there was no obvious evidence of clinical CWD.
Researchers indicated they were not surprised at the results since previous research in the park has shown that the elk herd in Rocky Mountain National Park and the Estes Valley, is larger, less migratory and more concentrated than it would be under natural conditions. Research has also shown that elk densities on the core winter range are the highest concentrations ever documented for a free-ranging population in the Rocky Mountains.
Over the next several years, in conjunction with the proposed lethal reduction of elk, researchers will continue to conduct studies to evaluate procedures for testing live elk for CWD. Currently, there is a live CWD test effective for deer, but CWD diagnosis in live elk has received limited evaluation to date. Until now, the disease could only be reliably diagnosed after death in elk. Any elk which tests positive for CWD will be lethally removed from the population, thereby contributing to annual population reduction targets. These targets will be developed each year based on annual population surveys and hunter success outside the park. Over the next three years elk population reduction will gradually remove study elk and the CWD status will be evaluated.
Chronic wasting disease (CWD) was first reported in free-ranging wildlife in 1981. It is a member of the transmissible spongiform encephalopathy (TSE) disease family which also includes bovine spongiform encephalopathy in cattle (BSE, also known as Mad Cow disease) and scrapie in domestic sheep and goats. CWD is fatal in deer and elk. Northeastern Colorado (including the eastside of Rocky Mountain National Park), southeastern Wyoming and western Nebraska are considered the endemic area for the disease.
Participants in the studies include scientists from the Colorado State University Department of Biomedical Sciences, the National Park Service, USDA National Wildlife Research Center, Colorado State University Department of Microbiology, Immunology and Pathology; USDA Agricultural Research Service. The Colorado Division of Wildlife is participating in the study on the live CWD test.