Lesson 12 - Chronic Wasting Disease

Lesson Title: Lesson 12: Chronic Wasting Disease Student Objectives (Enablers) As a result of this lesson, the student will … 1. Identify and explain Chronic Wasting Disease (CWD). 2. Identify on the map where CWD has been confirmed 3. Develop a public service announcement about CWD. Time: Instruction time for this lesson: 50 minutes. Resources: Insert Reference Materials Here Key Terms Chronic Wasting Disease Prion Spongiform Encepalopatheis BSE Interest Approach Before students arrive have classroom set up with DOW CWD signs and information all over the room. Have the handouts prepared and the topic on the board for the students to examine as they enter. If you have a large deer or Elk rack to use as a focus point upon students entering the room that would increase interest. Ok, today I want to discuss an important topic to our State of Colorado. This killer has been on the rampage for 40 years. It is called CWD or Chronic Wasting Disease. At this time would you get pout a piece of paper and fold it vertically three ways. (Demonstrate) Now Title each column in the following manner. 1. What I know about CWD. 2. What I would like to know about CWD. 3. What I learned About CWD. Great everyone is ready to complete some statements in columns one and two. Give the students 2-3 minutes to complete. Check to make sure students are working on the questions. Discuss some of the responses with the class. Excellent thoughts class!! Let’s begin today’s lesson by taking out your student worksheet and following along with the following presentation. Handout student worksheet Summary of Content and Teaching Strategies Objective 1. Identify and explain Chronic Wasting Disease Objective 2 Identify on the map where CWD has been confirmed Please follow along and answer the questions on your worksheet. If you have questions or comments please raise your hand and let’s discuss them. Begin the slide show. Go through the slide show allowing the students plenty of time to complete. Objective 3. Develop a public service announcement about CWD. I believe its time to develop a public awareness announcement to inform our local community about the facts of CWD. Divide the group into groups of 2-3 students per group. Hand out the USDA fact sheet on “Chronic Wasting Disease” to each student. In your group, read the fact sheet on CWD. Your job as a group is to develop a public service announcement on CWD. Discuss the information and how you might create a factual message to the public. The format can be an ad, a short essay, an audio announcement or a video. It needs to include the following: An explanation of the disease How the disease is transmitted How it affects humans and other animals Suggested safety tips for meat consumption / preventative measures Assessment will be on the following (See student copy) Have students present their PSAs. Have a local Division of Wildlife officer come in and evaluate the presentations. Review/Summary. Application Extended classroom activity: Research further explanation of prion studies in medicine. View a PBS, DOW or Discovery video on Chronic Wasting Disease Develop a prepared speech on CWD. FFA activity: Give the presentations at one of the chapter meeting. Select a winner to present to an area middle school. SAE activity: Have a CDC researcher come to the class to discuss the career opportunities in research. Evaluation. Student worksheet and group presentations. Chronic Wasting Disease Student Worksheet Name: 1. Define ‘Chronic Wasting Disease” 2. List the States where CWD has been located in captured animals. 3. List the States where CWD has been identified in the wild. 4. What are the symptoms of CWD in Deer and Elk? 5. What causes CWD in the animal? 6. What is the current diagnosis for CWD? 7. Is there any treatment for CWD? 8. Have there been any reports on humans contracting CWD? 9. What are some suggested preventions for the disease. 10. Response to your friend: Public Service Announcement Student Handout Your group has been selected to create a public service announcement about ____________________________________________________________. Time: 40 minutes The format can be an ad, a short essay, an audio announcement or a video announcement. You need to include the following: An explanation of the disease How the disease is transmitted How it affects humans and other animals Suggested safety tips for meat consumption / preventative measures Everyone in the group must have a speaking role at some point in the presentation. Presentations are limited to 10 minutes max. Assessment: You will be evaluated in the following manner: 20 points for all members speaking 20 points for time limit 20 points for clarity 20 points for completeness 20 points for point of view ____ ____ ____ ____ ____ 100 point total ____ Teacher Signature _____________________________________ Division of Wildlife Officer_____________________________________ Chronic Wasting Disease Veterinary Services November 2002 Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk. To date, this disease has been found only in cervids (members of the deer family). First recognized as a clinical "wasting" syndrome in 1967 in mule deer in a wildlife research facility in northern Colorado, it was identified as a TSE in 1978. CWD is typified by chronic weight loss leading to death. There is no known relationship between CWD and any other TSE of animals or people. In the mid-1980s, CWD was detected in free-ranging deer and elk in contiguous portions of northeastern Colorado and southeastern Wyoming. In May 2001, CWD was also found in free-ranging deer in the southwestern corner of Nebraska (adjacent to Colorado and Wyoming) and later in additional areas in western Nebraska. The limited area of northern Colorado, southern Wyoming, and western Nebraska in which free-ranging deer and/or elk positive for CWD have been found is referred to as the endemic area. Soon after diagnosis of the disease as a TSE, Colorado and Wyoming wildlife management agencies stopped the movement of deer and elk from their research facilities; wild cervids have not been translocated from the endemic area. In 2002, CWD also has been detected in wild deer in south-central Wisconsin, southwestern South Dakota, the western slope of Colorado, southern New Mexico, and northern Illinois. CWD also has been diagnosed in farmed elk and deer herds in a number of States and in two Canadian provinces. The first positive farmed elk herd in the United States was detected in 1997 in South Dakota. Since then, 25 additional positive elk herds and two positive farmed deer herds have been found: South Dakota (7), Nebraska (4), Colorado (10), Oklahoma (1), Kansas (1), Minnesota (1), Montana (1), and Wisconsin (2). As of October 2002, three of these 27 positive herds remain under State quarantine. Twenty-three of the herds have been depopulated or have been slaughtered and tested, and the quarantine has been lifted from one herd that underwent rigorous surveillance with no further evidence of disease. CWD also has been found in farmed elk in the Canadian provinces of Saskatchewan and Alberta and in free-ranging mule deer in Saskatchewan. For more information on CWD in Canada, visit the Canadian Food Inspection Agency Web site at www.inspection.gc.ca/english/anima/heasan/disemala/cwdmdce.shtml. Species that have been affected with CWD include Rocky Mountain elk, mule deer, white-tailed deer, and black-tailed deer. Other ruminant species, including wild ruminants and domestic cattle, sheep, and goats, have been housed in wildlife facilities in direct or indirect contact with CWD-affected deer and elk with no evidence of disease transmission. There is ongoing research to further explore the possibility of transmission of CWD to other species. Causative Agent The agent responsible for CWD (and other animal TSEs, such as scrapie and bovine spongiform encephalopathy) has not been completely characterized. There are three main theories on the nature of the agent that causes CWD: (1) the agent is a prion, an abnormal form of a normal protein, known as cellular prion protein, most commonly found in the central nervous system. The abnormal prion protein “infects” the host animal by promoting conversion of normal cellular prion protein to the abnormal form; (2) the agent is an unconventional virus; (3) the agent is a virino, or “incomplete” virus composed of nucleic acid protected by host proteins. The CWD agent is smaller than most viral particles and does not evoke any detectable immune response or inflammatory reaction in the host animal. Based on experience with other TSE agents, the CWD agent is assumed to be resistant to enzymes and chemicals that normally break down proteins, as well as resistant to heat and normal disinfection procedures. Clinical Signs Most cases of CWD occur in adult animals. The disease is progressive and always fatal. The most obvious and consistent clinical sign of CWD is weight loss over time. Behavioral changes also occur in the majority of cases, including decreased interactions with other animals, listlessness, lowering of the head, blank facial expression, and repetitive walking in set patterns. In elk, behavioral changes may also include hyperexcitability and nervousness. Affected animals continue to eat grain but may show decreased interest in hay. Excessive salivation and grinding of the teeth also are observed. Most deer show increased drinking and urination. Diagnosis Research is being conducted to develop live-animal diagnostic tests for CWD. Currently, definitive diagnosis is based on postmortem examination (necropsy) and testing. Gross lesions seen at necropsy reflect the clinical signs of CWD, primarily emaciation. Aspiration pneumonia, which may be the actual cause of death, also is a common finding in animals affected with CWD. On microscopic examination, lesions of CWD in the central nervous system resemble those of other TSEs. In addition, scientists use a technique called immunohistochemistry to test brain tissue for the presence of the abnormal prion protein to diagnose CWD. Epidemiology The origin and mode of transmission of CWD is unknown. Animals born in captivity and those born in the wild have been affected with the disease. Based on epidemiology, transmission of CWD is thought to be lateral or from animal to animal; although maternal transmission may occur, it appears to be relatively unimportant in maintaining epidemics. Surveillance Surveillance for CWD in free-ranging deer and elk in Colorado and Wyoming has been ongoing since 1983 and has helped define the core endemic areas for the disease in those States. CWD in free-ranging deer in Nebraska was detected in 2000/2001; more intensive surveillance to better define the prevalence and distribution of the disease in free-ranging deer in Nebraska is underway. In addition, an extensive nationwide surveillance effort was started in 1997-98 to better define the geographic distribution of CWD in free-ranging cervids in the United States. This surveillance effort is a two-pronged approach consisting of hunter-harvest cervid surveys conducted in many States, as well as surveillance throughout the entire country targeting deer and elk exhibiting clinical signs suggestive of CWD. Over 15,000 harvested free-ranging deer and elk have been tested to date, including over 13,000 animals harvested from outside of the endemic area. The recent finding of CWD in wild deer in areas far removed from the known endemic area has resulted in the development of plans for intensive surveillance in the 2002-2003 hunting season to better define distribution of the disease in wildlife in the United States. Surveillance for CWD in farmed elk began in 1997 and has been a cooperative effort involving State agriculture and wildlife agencies and the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS). Farmed cervid surveillance has been increasing each year since 1997 and will be an integral part of the USDA program to eliminate CWD from farmed elk. Management In each State where CWD has been detected in wildlife, State wildlife agencies have enacted response and/or management plans. APHIS has provided assistance to State officials in diagnosing CWD and in monitoring international and interstate movements of animals to help prevent further spread of CWD. Also, APHIS is developing a program to eliminate CWD from farmed elk. In addition, many State animal health regulatory agencies have instituted CWD programs for farmed elk. All of these agencies are committed to limiting the distribution of the disease in free-ranging deer and elk to the current localized area and decreasing its occurrence in both the freeranging and farmed deer and elk populations. National CWD Program In May 2002, Congress requested that USDA and the Department of Interior develop a plan to assist State wildlife management and agriculture agencies with CWD management. A CWD task force was formed to ensure that Federal and State agencies cooperate in the development and implementation of an effective national CWD program. The task force delivered the Plan for Assisting States, Federal Agencies, and Tribes in Managing Chronic Wasting Disease in Wild and Captive Cervids to Congress in June 2002 and is currently developing an implementation document for the plan. The plan addresses CWD diagnostics, communication, information dissemination, management, research, and surveillance.