The Facts on CWD (Chronic Wasting Disease)

Chronic Wasting Disease (CWD) in deer and elk species is a concern of all people who appreciate wildlife, and especially conservation hunting ranchers whose livelihoods depend on these animals.  Unfortunately, there is confusion and plenty of misinformation about this disease.

According to the Chronic Wasting Disease Alliance, these are the basic facts about CWD:

  • CWD is a neurological disease that degenerates the brain cells of infected animals and brings about emaciation (one of the symptoms of the disease).
  • It is a disease caused by a prion—a protein infection that converts the other proteins into the diseased form.
  • The disease affects only some cervids, primarily mule deer, white-tailed deer, elk, and moose.
  • CWD is contagious between cervids, but it is not believed to be able to naturally spread to other livestock or to humans.
  • It is not “mad cow disease” for deer, but officials still urge caution when dealing with diseased animals.

A recently updated study by the Michigan Department of Natural Resources provides an excellent overview of some of the current science on CWD.

  • Prions can be found in the environment and are often present there for a significant amount of time.
  • There is little evidence of significant interaction between elks and deer on conservation hunting ranches and in the wild, so therefore, transmission risk is very low. (And even so, some state officials are more concerned about wild animals infecting animals on conservation hunting ranches.)

Where did CWD originate?

  • Computer modeling of the spread of this disease shows that free-ranging mule deer may have carried CWD for over 40 years.
  • The disease was first found in a Colorado research facility in the 1960s.
  • There are two theories as to how it originated:
    • Most believe that CWD came from a similar disease, scrapie, that affected domestic sheep in the early part of the last century.
    • CWD may have also occurred spontaneously in the wild, which is possible for this type of disease.

Conservation hunting ranches are essential in the fight against CWD.

  • Testing for CWD is done by sampling brain tissue, meaning that such testing can only occur after a deer or elk is dead. In many states, regulations require that captive cervids are tested. In other states, there are voluntary programs for CWD testing which many ranches participate in. The federal government also requires testing at ranches and other facilities that move cervids interstate. Because of this stringent testing regime, conservation hunting ranches will be able to know if there is an imminent outbreak.
  • The difficulties in tracking the disease are that it occurs so often in free-ranging cervids. There is a need for detailed detection and monitoring systems, as outlined by the U.S. Geological Survey study from this year. Animals on ranches have a lower risk of exposure to the disease.
  • This positive culture surrounding hunting encourages hunter recruitment, which is one of the best ways to control the disease and deer population for the occurrences in the wild. This is in stark contrast to the opponents of conservation hunting, who would rather have no hunting at all. But overpopulation of deer makes the spread of disease easier, along with increasing the risk of malnourished animals as animals compete for limited amount of food.