Ashley Long, Stamper, Lucas
CWD is a disease that affects the nervous system in white-tailed deer, mule deer, red deer, elk, moose and other cervids. It is one in a group of diseases called the transmissible spongiform encephalopathies, which include scrapie in domestic sheep and goats and bovine spongiform encephalopathy in cattle. The disease is caused by misfolded proteins (prions) that are replicated by host animals. Prions interrupt and degrade nerve cells and ultimately eliminate basic nervous system functions, resulting in death of the infected host. The precise origins of CWD are unknown, but the condition was first detected in 1967 in a research mule deer herd in Colorado. It has now been confirmed in 25 states and two Canadian provinces. CWD has not been detected in Louisiana, but cases have been reported from all adjacent states.
Click here to see a time series map of states and provinces with CWD detections in wild or captive cervids.
These symptoms appear 16 to 36 months after infection. Because these symptoms are common to many diseases, a positive diagnosis of CWD requires laboratory testing by a trained professional.
CWD is spread among infected animals by direct and indirect contact with saliva, urine, feces or a carcass. These prion-carrying sources are deposited on the ground and in the soil and can be picked up by other animals during foraging. Reservoirs of prions in the environment (e.g., plants) may also enable transmission. Though mother-offspring transmission is possible, lateral transmission between two animals is the typical route for infection.
There is no evidence to suggest that CWD can be transmitted to traditional domestic livestock (e.g., cattle, sheep and goats) or humans. However, it is good to be cautious. Experts advise hunters to harvest only healthy-looking animals. Sickly looking animals should be assessed for disease and not consumed. Prions accumulate densely in the brain, eyes, tonsils, spine, spleen and lymph nodes of sick animals, so hunters should avoid touching or eating these parts. In areas affected by CWD, bone out carcasses in a way that removes all nervous system tissue. Be sure not to cut meat with saws or knives that were used to cut bone. To prevent exposing other susceptible animals to infected material, bury the carcass at least 6 feet deep or dispose of them in approved landfills.
There is no vaccine to prevent infection. Once an animal infected there are no effective treatments, but researchers are working to develop such tools. The best way to prevent the spread of CWD for now is to manage susceptible animal populations. The easiest solutions are to (1) remove and properly dispose of potentially infected animals, (2) prevent high densities of susceptible animals by continuing to hunt and harvest and (3) minimize places where susceptible animals congregate, such as feeding stations.
Adherence to carcass importation regulations — available online at http://www.wlf.louisiana.gov/hunting/CWD — is paramount to prevent inadvertently bringing CWD into Louisiana.
Prevention provides the best chance of minimizing the spread of the disease. The best way to help is to be vigilant and carefully follow any requests or regulations from LDWF. In addition, encourage your fellow Louisianans to remain calm and work to prevent the spread of misinformation.
Ashley M. Long, Assistant Professor of Wildlife Ecology, Louisiana State University
John M. Tomecek, Assistant Professor and Extension Wildlife Specialist, Texas A&M University
Lucas Stamper, Assistant Extension Agent, LSU AgCenter