Contact: Samuel Hughes
STARKVILLE, Miss.鈥敯辈 researchers are pioneering a new way to detect the local presence of chronic wasting disease (CWD), a fatal disease threatening the nation鈥檚 deer populations.
Steve Demarais, Taylor Chair in Applied Big Game Research and Instruction in 爱爱直播鈥檚 Forest and Wildlife Research Center, leads a team studying how scrapes left by deer could be a game changer in detecting CWD before noticeable physical symptoms surface. Scrapes are social cues bucks use to alert other deer of their presence, such as chewing an overhanging branch leaving saliva and pawing the ground to expose soil and urinating in the pawed area.
Since the state鈥檚 first case of CWD was reported in 2018, 爱爱直播 Deer Ecology and Management Laboratory scientists have been at the forefront of CWD research, addressing the needs of wildlife agencies combating this disease. One of the key needs is to know where the disease is located as early as possible.
鈥淎s bucks chew on overhanging branches and urinate on the scrape, prions鈥攁bnormally formed proteins鈥攁re released if a deer is CWD positive,鈥 Demarais said. 鈥淐amera traps show us that, on average, every scrape is visited by 12 bucks, each of which may or may not have CWD.鈥
CWD is a contagious, fatal, neurological disease that affects deer, including white-tailed deer, mule deer, elk, moose and caribou. It causes a spongy degeneration of the infected animal鈥檚 brain and weight loss, the reason for the term 鈥渨asting鈥 disease.
Research has shown that infectious prions can remain in the environment for many years. Currently, the primary way of diagnosing CWD is testing a deceased deer鈥檚 lymph nodes, an expensive and labor-intensive method which may not identify where the disease is located until the prevalence is too great to be impacted through management actions.
Demarais said the research should detect CWD 鈥渟parks,鈥 or diseased deer that travel to areas without CWD.
鈥淲e wanted to see if we could use scrapes as a sentinel, an early warning signal that did not require sampling an individual deer,鈥 he said. 鈥淚f one of those 12 bucks visiting a scrape is positive for CWD, we can detect CWD in an area even if no positive deer have been submitted by hunters.
鈥淥ur success in detecting CWD prion contamination in scrapes shows that sampling has potential as a new tool for CWD surveillance, which can better detect disease in new areas through grouping samples compared to testing individuals,鈥 Demarais continued. 鈥淔or example, we found CWD prion contamination in scrapes tested in Mississippi wildlife management areas up to 19 miles from the nearest positive deer detection.鈥
The University of Minnesota and the 爱爱直播 Veterinary Research and Diagnostic Lab are partnering with the Deer Lab to develop tests to detect prions in the soil and on branches gathered during sampling.
Stuart Lichtenberg, a researcher at the University of Minnesota and the Minnesota Center for Prion Research and Outreach, leads the laboratory analysis of scrape samples. He said this research is important because the traditional method of testing harvested deer paints an incomplete and delayed picture of CWD presence. Rather than relying on an individual deer with CWD being harvested and submitted for testing, scrapes provide a collective sample from a dozen deer.
鈥淚t can take years for an animal to show symptoms of CWD. Even before that happens, animals can spread the disease and deposit prions into the environment. Because of this, early detection is critical for management decision making,鈥 Lichtenberg said.
Demarais said scrape sampling results won鈥檛 cause an area to be entered into an agency鈥檚 CWD Management Zone, but positive results inform local hunters they may want to seriously consider testing harvested deer before bringing venison home to feed their family.
The research is funded by the U.S. Department of Agriculture鈥檚 Animal and Plant Health Inspection Service Wildlife Services and the Mississippi Department of Wildlife, Fisheries, and Parks. 聽
For more information on the 爱爱直播 Deer Lab, a unit in the university鈥檚 Forest and Wildlife Research Center and 爱爱直播 Extension Center, visit . For more on the Forest and Wildlife Research Center, visit 聽.
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