A white-tailed deer collected Jan. 25, 2018, in Issa-quena County, Mississippi, tested positive for chronic wasting disease (CWD).
The deer was a 4.5-year-old male that died of natural causes and was reported to the Mississippi Department of Wildlife, Fisheries, and Parks. That was the first time an animal in Mississippi had tested positive for the disease, fatal to white-tailed deer.
This article, first in a three-part series, will take a closer look at CWD. It will touch on the various challenges posed by this disease and begin to update you about the status of CWD and what science can tell us about it today.
CWD is an infectious prion disease that occurs in at least five cervid species. The CWD prion is an infectious agent comprised of misfolded cellular protein. Cervids are hoofed mammals in the deer family. The native North American cervid species in which CWD has been found are the white-tailed deer, mule deer, Rocky Mountain elk, moose and caribou.
CWD belongs to a group of diseases known as transmissible spongiform encephalo-pathies (TSEs). Mad cow disease, although distinctly different from CWD, is also a TSE. CWD affects the body’s nervous system.
Once in the host’s body, CWD prions transform normal cellular prions into an abnormal shape that accumulates until the cell ceases to function. It causes a characteristic spongy degeneration of the brain resulting in loss of appetite, loss of weight, an insatiable thirst, abnormal behavior, loss of body functions and death. Cervids infected with CWD tend to stay away from herds, walk in patterns, carry their head low, salivate and grind their teeth.
The disease has gone from minor scientific curiosity to national crisis since the syndrome was first recognized in the late 1960s.
Many facets of CWD biology and ecology are now well understood, but science-based, effective management and control strategies remain comparatively incomplete.
Eradicating CWD will not be easily done given its extensive distribution and other attributes. Flexible and responsive approaches for containing it and reducing infection and transmission rates have shown promise and deserve further attention. Such pursuits undoubtedly will be more difficult to obtain support for, particularly when disease control measures will negatively impact or conflict with commercial enclosures or hunting.
We believe there are two important motivations for making progress toward sustainable containment and control strategies for CWD in the coming decades. First, data from several sources suggests that heavily infected cervid populations will not thrive in the long term. Second, data on CWD prions and experience with other animal prion diseases suggest minimizing human exposure to these is prudent.
Moving forward, we believe this wildlife disease merits great attention. Collective experiences and observations made can serve as a solid foundation for wildlife and animal health professionals to build upon in addressing CWD in decades to come.
In the next installment, we will continue our overview of CWD with the second of this three-part series.
James L. Cummins is executive director of Wildlife Mississippi
