An Update on the Status of Chronic Wasting Disease

There continues to be quite a lot of interest from sportsmen and Missourians in Chronic Wasting Disease (CWD) and the potential for this disease to infect Missouri’s whitetail deer population. As of October 2003, CWD has not been found in Missouri. CWD is one of a group of diseases known as transmissible spongiform encephalopathies (TSEs) which include such diseases as scrapie in sheep, BSE (Mad Cow Disease) in cattle and Creutzfeldt-Jakob disease in humans-all diseases of the nervous system that result in distinctive lesions in the brain. CWD is a disease of wildlife that affects elk, white-tailed deer, and mule deer. It has not been documented in livestock or humans.

In fact, the World Health Organization, the U.S. Centers for Disease Control and Prevention and the National Institutes for Health have found no link between CWD and similar human diseases. Veterinary health officials also report no evidence to date that indicates that CWD is a threat to domesticated animals. Current research also shows no evidence that CWD can spread to livestock such as cattle.

However, the spread of CWD in wild animals such as white-tailed deer and other cervids is of great concern to wildlife managers. While the disease was originally described in captive animals about 30 years ago, it has recently been detected in wild herds in several western and midwestern states and Canada. In 2002, CWD was detected in wild deer in South Dakota, Wisconsin and New Mexico, and researchers are not sure how the disease is spread. Many speculate that CWD could have been spread long distances as a result of interstate shipment of infected animals. It is thought that CWD can also be spread through the natural movement of wild deer or elk. Once the disease becomes established, scientists are not sure how CWD spreads from one animal to another although some pathways may be through animal-to-animal contact. Symptoms of the disease include changes in natural behavior, and some animals exhibit extreme weight loss, excessive salivation, stumbling and tremors. CWD is thought to be always fatal to the infected animal but it can take many months or years before symptoms or infection appear. Remember, CWD has never been linked to disease in humans.

In animals with CWD, the disease agent (prion) has not been found in lean, skeletal muscle – which is what we eat. If you are concerned about any disease or parasite, it is recommended that you consider wearing rubber gloves while field dressing and processing your deer.

The Missouri Departments of Conservation and Agriculture are working together to help keep deer and elk from CWD infected states out of Missouri. The Department of Conservation also continues to monitor the health of the state’s deer herd by collecting tissue samples from hunter-volunteers at deer check stations in selected counties. Last year tissue samples from over 5,900 deer taken by hunters (from 30 counties) during the November firearm season were tested for CWD. All test results were negative. The Department of Conservation will continue to monitor the state’s deer herd for CWD. These efforts will take place in 30 counties during 2003.

Additional information on CWD and the monitoring efforts that are being conducted can be accessed at the following Web site: www.conservation.state.mo.us/hunt/cwd/facts.htm as well as from the United States Department of Agriculture Animal Plant Health Inspection Service (USDA APHIS) Web site at www.aphis.usda.gov/lpa/issues/cwd/cwd.html

Robert Pierce, Extension Wildlife Specialist, UMC (573) 882-4337