Department of Defense
Congressionally Directed Medical Research Programs
2002 National Prion Research Program

In 2002, WVRG wrote a proposal to the US Department of Defense regarding testing for CWD.

The text of this proposal follows.

Part of the proposal included the information in this document (PDF).

The US Army responded to this proposal with this letter (PDF).

Lay Abstract

Chronic wasting disease (CWD) is a fatal brain disease of deer and elk caused by an unusual infectious agent called a prion. How prions are spread between animals is not understood, but it is known that prion diseases can "jump' between different species if meat from an infected animal is eaten. A good example of this is the spread of mad cow disease from cattle to humans as occurred in Great Britain during the 1990's. Mad cow disease is a close relative of CWD, and both diseases have a great deal in common.

CWD was first detected in the whitetail deer herd of Wisconsin in 1999, a finding of great importance since previous to that time the disease was not thought to exist east of the Mississippi River. The fear now is that it will continue to spread eastward into the large deer herds of Michigan, Pennsylvania and other eastern states.

The presence of CWD in Wisconsin is of particular importance since the whitetail deer herd is large (over 1.6 million animals) and deer hunting and eating venison are important aspects of Wisconsin's history and culture. Since it is unsafe to eat meat from CWD infected animals, roughly 25% of the state's hunters will not participate in the hunt during the fall of 2002. This raises the possibility of the deer herd expanding out of control, leading to animal starvation, severe crop damage and an increase in deer-automobile accidents which are virtually always fatal for the deer and can be fatal to the humans involved.

Therefore, it is important that we learn as much about CWD in Wisconsin as possible to help authorities confront it and limit it's spread. Our research proposal is aimed at gathering some of that important information.

We have designed a system that will allow deer hunters to prepare and ship tissue samples from the deer that they harvest during the hunting season to our laboratory. We will then use a sophisticated test to determine whether the animal is CWD infected. Testing results will be shared with the hunter who submitted the sample to aid him or her in deciding whether or not to eat the venison from the animal. The laboratory will freeze the tissue sample left over from the testing and organize the data concerning it (location of the deer kill, age and gender of the deer, etc.) into a computer based database. This database will allow our laboratory and other researchers to identify CWD positive and negative samples for study with respect to the biochemical properties of the prions, the types of cells infected and the locations and characteristics of the infected animals.

The other project that we propose is to begin to analyze CWD positive and negative animals to determine whether there are genetic traits (i.e. particular genes) that help to determine which animals become infected and which animals are resistant to the infection.

When the proposed studies are complete, we will know a great deal about CWD in Wisconsin, and this information may help other states to deal with this deadly disease.

Technical Abstract

Background: Chronic wasting disease (CWD), a transmissible spongiform encephalopathy, was first detected in the whitetail deer herd in Wisconsin in February, 1999. Studies by the State Department of Natural Resources (DNR) have now documented that in focal areas the incidence of CWD infection is at least 3% in the deer herd and that the disease is present in captive deer game farms. The full extent of the CWD infection in the state is unknown. The presence of CWD in Wisconsin is important for two main reasons. First, the occurrence of variant Creutzfeldt-Jacob disease (CJD) in Europeans who ate beef from cattle with bovine spongiform encephalopathy raises the possibility that CWD may "jump" into humans since venison is commonly eaten in Wisconsin. Second, Wisconsin has a very large whitetail deer herd and deer hunting and the consumption of venison are important parts of Wisconsin's history and culture. Further, spread of CWD in the wild whitetail deer herd of Wisconsin is particularly important since it not only poses a real threat to human health but also puts at risk a state industry that produces hundreds of million dollars in revenue per year

Objective: Our laboratory has positioned itself to aid in the study of CWD incidence in Wisconsin, to construct an extensive bank of tissues from CWD positive and CWD negative deer and to begin the evaluation of Wisconsin's whitetail deer for genetic traits that may influence their susceptibility and resistance to the disease. In the fall of 2002 and every year thereafter, our laboratory will gather lymph node samples from wild whitetail deer in Wisconsin and test them for CWD. Materials are being distributed through retail merchants to deer hunters in the state with specific instructions and equipment needed for the removal of the throat tissues of the deer and the shipping of the tissues to our laboratory. Upon receipt in the laboratory, the retropharyngeal lymph nodes will be dissected from the tissue sample and tested for CWD prions by means of an ELISA technique.

Specific Aims: There are three fundamental goals of the proposed studies:

• Test samples of retropharyngeal lymph nodes from approximately 25,000 whitetail deer from across the state of Wisconsin for CWD. This will provide extensive information concerning the epidemiology of the disease, its extent within the state and may provide insights into its mode or modes of transmission.
• Use CWD positive and negative tissues so obtained to establish a tissue bank of to be used by our and other laboratories in research projects concerning the biology, biochemistry and genetics of the disease. Such tissues are currently scarce and largely unavailable to both private and government researchers.
• Begin a preliminary study of the genetics of resistance and susceptibility to CWD in whitetail deer. The initial procedures to be used in these studies will involve comparing the prion genes from CWD positive and negative deer for the number of different alleles present. The importance of such allelic variation has been shown in both scrapie and iatrogenic CJD

Study Design: Beginning in the fall of 2002, boxes are being distributed to retail merchants who specialize on hunting and outdoor products that contain the materials necessary for the hunters to prepare a specific tissue sample for shipment to our laboratory. Upon receipt in the laboratory, the retropharyngeal lymph nodes are dissected from the throat patch and are subjected to CWD testing by means of an enzyme immunoassay (EIA) procedure. The CWD positive and negative samples will be archived in freezers and a database will be generated to allow identification of samples for research protocols. Initial studies will used molecular biologic techniques to examine the genetics of prion genes in the whitetail deer.

Relevance: To understand the prevalence and distribution of CWD in Wisconsin will greatly enhance the ability of authorities respond to and limit the spread of the deadly disease. A research oriented tissue bank will expedite both basic and applied research.