For the third consecutive month, chronic wasting disease (CWD) has staked a claim in new territory. On March 17, the North Dakota Game and Fish Department (NDGFD) announced that a hunter-killed mule deer taken last fall tested positive for CWD, reports the Wildlife Management Institute. This announcement raises the total number of states and provinces currently managing CWD in captive or wild cervid populations to 20.

Taken on fee title land within the Standing Rock Reservation in Sioux County, the infected buck was submitted by a hunter who noticed that the animal was very thin and appeared to be sick. According to agency protocol, the NDGFD sent a sample from the deer to the University of Minnesota Diagnostic Laboratory, where 3,000 other samples collected during North Dakota's 2009 hunting season were being tested for CWD. To date, CWD has not been detected in any of the other animals sampled in 2009.

The origin of the infected buck remains unclear. The closest documented cases of CWD to Sioux County are more than 200 miles away in western South Dakota. However, all of North Dakota's bordering states and provinces, with the exception of Manitoba, are actively monitoring and managing for CWD in either captive or wild cervid herds.

Like many states, North Dakota began a CWD surveillance program in 2002. Relying mainly on hunter-submitted samples, the NDGFD has tested more than 14,000 deer, elk and moose to date. Until last month, all of those samples tested negative for CWD. According to Dr. Dan Grove, the NDGFD CWD Coordinator and a wildlife veterinarian, the NDGFD will increase the number of deer licenses issued for the hunting unit in which the infected deer was harvested. In addition, the NDGFD plans to continue and intensify its year-round targeted surveillance efforts.

"We have followed the reaction plan outlined in our CWD management plan and will likely revise it as we learn more about the status of the disease in North Dakota," said Grove. "Fortunately, we have several things going for us that should make managing CWD in Sioux County easier." He pointed out that the area where the infected buck was taken has a deer population density of only eight animals per square mile, and overall, a consistently high turnover in the population has resulted in a relatively young herd. Since CWD is most likely spread via animal-to-animal contact, low population densities and shorter individual life spans likely will reduce the speed of CWD transmission in the local herd if the disease is present in other animals.

While the NDGFD has taken several proactive steps to guard its cervid herds against CWD (such as a 2003 ban on the importation of cervids and cervid parts from CWD-infected areas), baiting still is allowed in North Dakota. Since the active agent of CWD, prions, can be found in the saliva and feces from infected animals, many other states have initiated moratoriums on baiting and feeding, because these activities significantly increase contact between animals. "Though we haven't banned baiting in the past, CWD has changed the game," noted Grove. "We might start thinking about a baiting ban in the future." (mcd)