Chronic Wasting DiseaseDisease DataChronic wasting disease (CWD) is a progressively degenerative fataldisease that attacks the central nervous system of membersof the deer family. To date it has been diagnosed in elk, mule deer,black-tailed deer, and white-tailed deer. CWD is one of a group of diseasesknown as transmissible spongiform encephalopathies (TSEs).These diseases are characterized as transmissible because they canbe transmitted from one infected animal to another. They are furtherclassified as spongiform due to the “spongy-like” areas which formin the brain of the infected animal, hence the encephalopathy portionof the name.The scientific community generally accepts that the infectiousagents of CWD are prions. Prions are abnormal proteins that seem tohave the ability to alter the structure of normal proteins found in thebody of the animal they enter. Logical natural methods of prion transmissioninclude, but may not be limited to, secretions and excretionsfrom infected animals. In a new study conducted this past year atColorado State University found that CWD can be transmitted experimentallyfrom saliva and blood. Also, human activity contributesto environmental prion contamination. Prions are hideously durableand impervious to most disinfectants and natural conditions, remainingin the environment for years.Animals suffering from CWD typically behave abnormally by separatingthemselves from their usual social group. They often standalone, with a drooped posture, and may not respond to human presence.As the disease progresses they will appear very skinny on closeexamination and will salivate, drink, and urinate excessively.The goal for the 2006 – 2007 monitoring period was to test approximately1,500 deer statewide. Routine testing involved Mississippihunters in this disease monitoring effort. Hunters throughoutthe state were asked to voluntarily submit the heads of harvesteddeer for CWD testing. Additionally samples were obtained from taxidermistsand deer processing facilities. Most of these samples camefrom wildlife management areas, national wildlife refuges, and DeerManagement Assistance Program (DMAP) cooperators.A total of 1,120 samples were taken from free-ranging white-taileddeer in Mississippi during 2006 – 2007. Samples were obtained fromhunter harvested animals, spring herd health evaluations, target animalsurveillance, and road-killed animals. Samples were obtainedfrom 72 counties (Figure 6). The samples were submitted to theSoutheastern Cooperative Wildlife Disease Study at the Universityof Georgia following the 2006 – 2007 hunting season and 1,089 ofthose samples were tested for evidence of the CWD agent using immunohistochemistry.The remaining 31 samples were not tested becausethe containers did not contain testable specimens. Evidenceof CWD was not detected in 1,087 of the tested samples and the remaining2 results cannot be considered official test results, becausethe correct specimens for testing were not available.to diagnose disease is dependent on quick reporting because deercarcasses deteriorate rapidly in Mississippi’s climate.In 1967 CWD was first recognized at a captive mule deer researchfacility in Colorado. A Wyoming research facility documented thedisease in deer and elk in 1978. CWD was then documented in freerangingdeer in Colorado and Wyoming in the 1980s. Further testingfrom 1996 through the end of 2001 found additional positive animals(either captive or wild elk or deer) in Kansas, Nebraska, Montana,Oklahoma, South Dakota, and the Canadian provinces of Saskatchewanand Alberta. Then in February 2002 the first case was confirmedeast of the Mississippi River in Wisconsin, in wild white-tailed deer.In 2004, CWD was found in New York and West Virginia. As of October1, 2007, there are 11 states with CWD infected wild populations(Colorado, Illinois, Kansas, Nebraska, New Mexico, New York, SouthDakota, Utah, Wisconsin, West Virginia, and Wyoming) and two Canadianprovinces (Alberta and Saskatchewan). Additionally, CWD hasbeen found in captive cervid populations in all of the above states aswell as Minnesota, Montana, and Oklahoma.All public health officials maintain that venison is safe for humanconsumption. However, hunters who wish to take additional stepsto avoid potential unnecessary contact with prions or environmentalcontamination can do the following:• Avoid shooting, handling, or consuming any animal that appearssick. Contact the MDWFP at 601-432-2199 if you see or harvestan animal that appears sick.• Wear latex gloves when field dressing or processing deer.• Avoid eating or contact with brain, spinal cord, spleen, lymphnodes, or eyes.• Cut through the spinal cord only when removing the head. Use aknife designated solely for this purpose.• Bone out meat to avoid cutting into or through bones. Remove allfat and connective tissue to avoid lymph nodes.• Dispose of all carcass material, including the head, in a landfill orpit dug for carcass disposal purposes.• Either process your animal individually or request that it be processedwithout adding meat from other animals.• Disinfect knives and other processing equipment in a 50% bleachsolution for a minimum of one hour.• Discontinue baiting and feeding which unnaturally concentratedeer.Deer With Chronic Wasting Disease from WisconsinThe MDWFP, in cooperation with the Mississippi Board of AnimalHealth and the U.S. Department of Agriculture/Veterinary Serviceswill continue target animal surveillance. A target profile animal is anyadult cervid that is emaciated and shows some neurological disorder.These target animals should be reported to the local county conservationofficer who has been trained to properly handle them and coordinatetheir transport to the appropriate laboratory for CWD testing.Most deer exhibiting symptoms of CWD are actually suffering fromother conditions or diseases common to white-tailed deer in Mississippi.Malnutrition, hemorrhagic disease, brain abscesses, and otherconditions may cause some of the same symptoms. However, due tothe seriousness of CWD and the importance of early detection andcontrol, it is necessary to test target animals for infection. The ability262006-2007 Mississippi Deer Program Report
Chronic Wasting DiseaseDisease DataFigure 62006-2007 Mississippi Deer Program Report27
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