Managing Chronic Wasting Disease

Testing for Chronic Wasting Disease (CWD) is being conducted in two areas of Minnesota this fall during deer season. Testing in southeast Minnesota (deer permit areas 348 and 349) is due to a CWD positive deer found within Iowa's borders in Allamakee County, which borders Minnesota. Testing in the north metro (part of deer permit areas 601 and 236) is a precautionary measure after CWD was discovered in a captive cervid farm in North Oaks in 2012.

LATE (3B) SEASON UPDATE:

MN DNR collected 375 samples over opening weekend in DPA’s 348 and 349 combined. To meet the surveillance goal of 450 samples, we will be collecting additional samples this 3B opening weekend at 2 registration stations in DPA 349. Internet and phone registration WILL NOT BE turned off.

Carcass import from other states/provinces:

In addition to the DNR's disease surveillance and management within the state, importation of cervidae (moose, elk, deer, caribou) carcasses from CWD endemic areas is also restricted. Carcasses may not be imported into the state from a CWD endemic area except for cut and wrapped meat, quarters or other portions of meat with no part of the spinal column or head attached, antlers, hides, teeth, finished taxidermy mounts, and antlers attached to skull caps that are cleaned of all brain tissue. If you plan to hunt outside the state, consult the Minnesota Board of Animal Health website for a map of areas from which import is restricted.

Deer permit areas 348 & 349 stations

Southeast Registration Stations

Sample Collection Sites

  • Brownsville - (Bissen’s Tavern) 202 S 3rd St, Brownsville, MN 55919
  • Houston - (Houston Amoco Food Shop) 801 E Cedar St Houston, MN 55943

Registration stations listed above will be staffed for sample collection 9 a.m. to 7 p.m. on November 22 and 23, 2014 during the opening weekend of the Late Southeast (3B) firearm's deer season. This is a voluntary surveillance for the hunters. Other registration stations and services (online and phone registration) will remain open during this time; however no samples will be collected from those sites.

 

 

North Metro


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No CWD found since initial 2010 discovery

Extensive sampling of nearly 1,000 deer during fall 2013 in southeastern Minnesota's deer permit area 602 did not detect a single case of Chronic Wasting Disease (CWD). More than 4,000 deer have been sampled within DPA 602 since the discovery of the index case with no additional detection found which lends confidence that DNR caught the disease on the front end of the infection. DPA 602 no longer exists and its borders are dissolved back to surrounding deer permit areas.

CWD-postive captive animal triggers north metro testing

In mid- 2012, a captive European red deer (Cervus elaphus) was found infected with CWD in a herd of approximately 400 animals in North Oaks, Minn. This marked the first time CWD was discovered in this species. In response, the Minnesota DNR collected samples from 154 deer in 2012 and another 134 in 2013 all within a 10-mile radius of the farm to test for CWD.

Sample collections included 24 vehicle-killed deer, 133 archery-killed deer from special metro hunts, and 131 deer from a city-contracted sharpshooting effort within North Oaks. All samples were negative for CWD. The Minnesota DNR plans to continue surveillance in the north metro in 2014.

Iowa CWD discovery triggers southeast testing in deer permit areas 348 & 349

Due to the discovery of CWD in Allamakee County Iowa in April 2014, the Minnesota DNR plans to conduct CWD surveillance in deer permit areas 348 and 349 along the Iowa border. The goal is to collect a minimum of 450 samples total between both permit areas.

Southeastern sampling*

 

North Metro sampling

CWD sampling in southeastern Minnesota

Click to enlarge map

 

*In 2014, deer permit area 602 has reverted back to the former permit areas (341 and 343).

 
What is CWD?

CWD (Chronic Wasting Disease) naturally occurs in North American deer, moose and Rocky Mountain Elk. It belongs to a group of infectious diseases known as "transmissible spongiform encephalopathies" (TSEs).

It is caused by an abnormal protein called a prion which affects the animal's brain and is invariably fatal. Usually, months to years pass from the time an animal is infected to when it shows signs of the disease.

The disease is found in 14 other states and two Canadian provinces, including the Midwestern states of Wisconsin, Illinois, North Dakota and South Dakota.

Typical signs of the disease include drooping head or ears, poor body condition, tremors, stumbling, increased salivation, difficulty swallowing, or excessive thirst or urination.

The diagram to the right illustrates the most common sites where prions accumulate in infected cervids.

CWD Diagram


When was CWD discovered?

The Minnesota Department of Natural Resources has confirmed that an adult female deer harvested during the 2010 hunting season has been diagnosed with Chronic Wasting Disease (CWD), a brain and nervous system disorder found in deer, elk and moose. This is disappointing news but the DNR is well prepared to address it.

The discovery occurred the week of Jan. 10, 2011, during laboratory analysis of more than 500 samples (lymph nodes) taken from hunter-harvested deer taken within a 20-mile radius of Pine Island in southeastern Minnesota. Initial screening of all other samples is complete. The DNR collects and evaluates lymph nodes because CWD can be detected through microscopic analysis.

The National Veterinary Services Laboratory in Ames, Iowa, confirmed the University of Minnesota's preliminary diagnosis of the single adult female white-tailed deer on Jan. 25, 2011.

How did the disease enter Minnesota's wild deer herd?

At this point, no one knows. In fact, we may never know. What is known is that the "presumed positive" deer was harvested about three miles southwest of a former domestic elk farm near Pine Island. The farm's elk herd was depopulated after a seven-year-old female elk tested positive for CWD in January 2009. Three additional elk were found to be infected with CWD during the depopulation effort. The closest wild deer with CWD in Wisconsin is 150 miles from the location this CWD-suspect deer was harvested in Minnesota.

What other states have CWD?

CWD is found in wild deer, elk or moose in 14 other states and two Canadian provinces, including Midwestern states of Wisconsin, Iowa, Illinois, North Dakota. For specifics, visit the CWD Alliance Website.

 

A map and list of states and counties with endemic areas where exportation of cervids is restricted is available from the Minnesota Board of Animal Health by clicking the Cervidae (Deer, Elk, Moose, Caribou, Reindeer) link.


What has DNR done to manage CWD?

The DNR has been actively on the lookout for CWD since 2002, when the disease was first found in a domestic elk farm in central Minnesota. An important management strategy for this disease is early detection. Since 2002, the DNR has tested more than 40,000 hunter-harvested, car-killed and targeted sick deer, along with 60 elk and 90 moose. Until now, laboratory analysis had never found a wild deer "presumed positive" for CWD.

Do you believe other deer in southeastern Minnesota have CWD?

That's possible but it's premature to speculate. The only way to know if other deer have CWD is to continue doing surveillance based on enacting our CWD Response Plan.

If I harvested a deer from that area, should I be concerned about eating the venison?

Based on the fact that only one deer has tested positive for CWD among more than 500 samples, the rate of occurrence is likely low. Still, people with venison in their freezer from this area should know the following:

  1. The National Center for Disease Control (CDC) and the World Health Organization (WHO) have found no scientific evidence that CWD is transferable from animals to humans; and
  2. The CDC advises against eating animals known to have CWD.

So, people with venison in their freezer that was harvested from this area will need to make decisions based on the information above. The Minnesota Department of Health – not the DNR – provides guidance to citizens on food consumption issues.

What else can you tell me about CWD?

CWD causes a characteristic spongy degeneration of the brains of infected animals resulting in emaciation, abnormal behavior, loss of bodily functions and death. CWD belongs to a group of diseases known as transmissible spongiform encephalopathies (TSEs). Though many observers try to compare CWD with "mad cow disease", the diseases are distinctly different.

What causes CWD?

The disease agent is a prion, an abnormal form of cellular protein that is most commonly found in the central nervous system and in lymphoid tissue. The prion "infects" the host animal by promoting conversion of normal cellular protein to the abnormal form.

Where and how did CWD originate?

The origin of CWD is unknown, and it may never be possible to definitively determine how or when CWD arose. It was first recognized as a syndrome in captive mule deer held in wildlife research facilities in Colorado in the late 1960s, but it was not identified as a TSE until the 1970s. Computer modeling suggests the disease may have been present in free-ranging populations of mule deer for more than 40 years.

How does CWD spread?

It is not known exactly how CWD is transmitted. The infectious agent may be passed in feces, urine or saliva. Transmission is thought to be lateral (from animal to animal). Although maternal transmission (from mother to fetus) may occur, it appears to be relatively unimportant in maintaining epidemics.

Because CWD infectious agents are extremely resistant in the environment, transmission may be both direct and indirect. Concentrating deer and elk in captivity or by artificial feeding probably increases the likelihood of both direct and indirect transmission between individuals. Contaminated pastures appear to have served as sources of infection in some CWD epidemics. The apparent persistence of the infectious agents in contaminated environments represents a significant obstacle to eradication of CWD from either captive or free-ranging cervid populations.

The movement of live animals is one of the greatest risk factors in spreading the disease into new areas. Natural movements of wild deer and elk contribute to the spread of the disease, and human-aided transportation of both captive and wild animals greatly exacerbates this risk factor.

Why should Minnesotans be concerned about CWD?

CWD poses serious problems for wildlife managers, and the implications for free-ranging deer, elk and moose are significant:

  • Ongoing surveillance programs are expensive and draw resources from other wildlife management needs;
  • Impacts of CWD on population dynamics of deer and elk are presently unknown. Computer modeling suggests that CWD could substantially reduce infected cervid populations by lowering adult survival rates and destabilizing long-term population dynamics;
  • Where it occurs, CWD may alter the management of wild deer and elk populations, and it has already begun to do so; and
  • Ultimately, public and agency concerns and perceptions about human health risks associated with all TSE's may erode hunters' confidence and their willingness to hunt in areas where CWD occurs.

Field Dressing

Improper handling of the deer can contaminate the carcass with potentially harmful bacteria and compromise food safety and quality. By implementing a few precautionary measures during field dressing, the hunter can help ensure the final product is fit to consume.


  1. Instructional Photo No. 1Place the deer on its back and spread the hind legs. Support the carcass in this position by using rocks or sticks. All hunters should wear gloves!


  2. Instructional Photo No. 2Cut along the midline of the belly from the breastbone to the anus. Avoid cutting into the intestines and stomach by turning the knife blade up during the cutting process. Slowly remove the skin from the incision.


  3. Instructional Photo No. 3Cut through the sternum to open the body cavity surrounding the lungs and heart.


  4. Instructional Photo No. 4After opening the body cavity, reach inside and begin cutting the diaphragm, lungs, and heart away from the body wall. Remove the internal organs all in one step. Take care to avoid puncturing or tearing the stomach and intestines during this process.


  5. Instructional Photo No. 5To promote cooling of the carcass, place a stick between the ribs to prop open the body cavity and allow airflow.

General Information

The Centers for Disease Control and World Health Organization state that there is no scientific evidence that CWD causes human Illness; however, precautions should be taken to minimize exposure.

  • Do not shoot, handle, or consume any animal that is acting abnormally or appears to be sick.
  • Contact your local DNR office or the general DNR information line at 1-888-646-6367 if the animal appears sick.
  • Wear latex or rubber gloves when field dressing your deer. Wash hands and instruments thoroughly after field dressing is completed.
  • Bone out the meat from your animal. Don't saw through bone, and avoid cutting through the brain or spinal cord (backbone). Minimize handling of brain and spinal tissue.
  • Wash hands and instruments thoroughly after field dressing is completed.
  • Avoid consuming brain, spinal cord, eyes, spleen, tonsils and lymph nodes. Normal field dressing coupled with boning out a carcass will remove most, if not all, of these body parts.
  • Avoid consuming the meat from any animal that tests positive for the disease.
  • If you have your deer or elk commercially processed, request that your animal is processed individually, without meat from other animals being added to meat from your animal.

Transportation and Processing

Proper handling and refrigeration is necessary to prevent decomposition of the carcass and minimize the growth of potentially harmful bacteria. This will reduce the risk of food-borne illness due to consumption of contaminated meat.

  • Drag the deer with the back or side down to minimize contamination of the meat. If possible, drag the deer on a tarp or use a deer cart.
  • Keep the carcass cool during transport to the locker plant.
  • Transport the carcass to the locker plant as soon as possible. If the carcass cannot be taken directly to the plant after harvest, it must be stored at a temperature of less than 41 degrees F.
  • Rinse the carcass with cold water prior to storage to remove debris and bacterial contamination.
  • When transporting the deer in a vehicle, pack the body cavity with ice to promote additional cooling.
  • Allow for adequate air circulation around the carcass and keep it out of direct sunlight and warm temperatures during transportation and storage.
Download the entire Field To Fork brochure pdf

Summary

Chronic wasting disease (CWD) is an infectious neurological disease that occurs in North American deer (Odocoileus spp.), Rocky Mountain elk (Cervus elaphus), and moose (Alces alces) and belongs to a group of diseases called transmissible spongiform encephalopathies (TSEs).

The disease is progressively fatal and has no known immunity, vaccine or treatment. Since 2002, more than 40,000 hunter-harvested and 650 opportunistic or targeted wild deer have been tested for CWD in Minnesota, with only one positive case identified in the wild.

This plan establishes general procedures to be followed for managing CWD if it is found in wild deer and procedures for wild deer surveillance if CWD is detected in a captive cervid facility or in bordering states.

If CWD is detected in wild cervids in Minnesota, the Minnesota Department of Natural Resources (MNDNR) has identified 4 primary goals of managing the disease:

  1. Determine and monitor the prevalence and geographic distribution of CWD in the affected area.
  2. Prevent or minimize further spread and new introductions of the disease.
  3. Support and conduct applied research on CWD and its epidemiology.
  4. Provide accurate and current information about CWD to the public, agency personnel, and constituent groups.
Download the entire response plan