Based upon sampling efforts of the past five years, chronic wasting disease (CWD) is currently not found in Nevada. In a continuing effort to monitor for CWD, the Nevada Department of Wildlife is stepping up its effort to collect samples from deer and elk for evaluation.
As part of this effort, says Mike Cox, NDOW Staff Biologist, “More than 25 NDOW employees from around the state of Nevada met in Elko with state veterinarians from the Nevada Department of Agriculture for a training session on collecting samples from deer and elk.”
CWD is a transmissible spongiform encephalopathy (TSE) that is found in deer and elk. It is believed to be caused by a mutated protein, called a prion that attaches to, and transforms healthy brain proteins into disfigured mutations that lead to a deterioration of the brain, and ultimately result in the death of the animal.
CWD is similar but different from scrapie (a disease found in domestic sheep), Bovine Sponfigorm Encephalitis (also referred to as “mad cow” disease) and Creutzfeld-Jakob disease (a TSE found in humans.) While similar to these diseases, there is no known causal link between CWD and other TSEs of animals or people. There is currently no evidence to indicate that CWD can be transmitted from elk and deer to livestock or humans. To date, CWD has been identified in parts of Colorado, Wyoming, Nebraska, South Dakota, Wisconsin, Illinois, New Mexico, Montana, Oklahoma, Kansas and most recently Utah, in the United States. In Canada it has been detected in the provinces of Alberta and Saskatchewan. In many of these areas, CWD was first identified in animals found in captive elk or deer game farms.
Cox explains that, “To test for CWD, a sample of the brain stem is generally taken from an animal within 48 hours of harvest. This training session was to train personnel unfamiliar with the technique as well as teach everyone a new sampling method, which requires the removal of lymph nodes from the animal’s throat.”
It is not definitively known how CWD spreads, however it appears that the disease may be transmitted through saliva, urine, and feces. This can occur either directly from animal to animal contact or indirectly, through soil or forage that is contaminated by body fluids. Current research indicates the prion does not accumulate in muscle tissue, but does collect in the brain, eyes, spinal cord, lymph nodes, tonsils and spleen of infected animals. Pressurized heat is the only method thus far found to kill the prion.
According to Cox, NDOW has identified two areas of concern with regards to potential transmission of CWD into Nevada. The first is transmission by an infected animal immigrating to Nevada from Utah. The second area of concern is that of hunters returning from out of state and dropping infected material from harvested animals into big game habitat.
As a result, NDOW has targeted sampling areas in Nevada where these two forms of transmission are most likely to occur. The first area of concern is big game units on the eastern side of the state where migration is likely to occur. The second sample area is around cities located in or adjacent to mule deer or elk habitat.
“Sampling efforts have been identified based on the potential risk of disease transmission into these areas,” explained Cox.
Hunters are being asked to voluntarily bring in the head and neck of harvested animals to check stations around the state. If a hunter is going to bring the head in, it should be kept cool and should be brought in as soon as possible after harvest, preferably within 48 to 72 hours.
However, if a hunter is planning on having taxidermy done on a trophy animal, it is not recommended that a sample be taken from that animal as it may damage the cape.
If hunters are hunting out of state, NDOW is requesting that a harvested animal be processed before bringing it back to Nevada. NDOW is also asking that boned out meat, antlers with bleached skull plate and hides be the only parts of deer and elk to enter the state from herds located outside of Nevada.
For more information about CWD or to find out where to take your harvested animal, go to NDOW’s web site at www.ndow.org.