While the results of some tests are still to come in, preliminary figure show 2 percent, or eight of the 216 mule deer and 123 whitetails killed in the special hunt in Carbon County this winter tested positive for Chronic Wasting Disease. CWD is a progressive, fatal neurological disease that effects deer, elk and moose.
The disease is similar to Mad Cow Disease, that jumped the species barrier from cattle to humans leading to deaths of more than 200. There are no known cases of CWD jumping the species barrier and infecting humans, but FWP recommends hunters take precautions when handling game to minimize risk.
Montana is surrounded by states — Wyoming and the Dakotas — where CWD is present. CWD is also present in Canadian provinces north of the border. The disease was first detected in mule deer killed in Carbon County near Bridger during the 2017 hunting season. The special hunt was approved in order to determine the extent of the disease in south-central Montana.
The Montana FWP commission has also called on Wyoming to close elk feeding grounds across that state. It's feared the feeding grounds will become hot spots for the disease, which is caused by abnormal proteins called prions. Prions are spread by body fluids such as urine, and can persist in the soil for years or maybe decades. The Bridger-area outbreak of CWD likely spread north from Wyoming.
There has also been a special hunt in northern Montana in Liberty County where mule deer killed in 2017 also tested positive for CWD. One deer killed in the special hunt tested positive for CWD.
CWD has been found in at least 23 states and two Canadian provinces. Only New York state appears to have prevented the establishment of the disease after it was detected in captive deer herds and a pair of wild whitetail.
The CWD Alliance is a good resource for info on CWD.