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Home | Management of Wildlife Disease | Chronic Wasting Disease Chronic Wasting Disease
Chronic wasting disease (CWD) was first described in captive deer more than 35 years ago near Fort Collins, CO. Since 1998, CWD has spread to wild and domestic animal populations in several states and provinces. It belongs to the family of diseases known as transmissible spongiform encephalopathies (TSEs), so called because these diseases cause microscopic holes in brain tissue giving it a sponge-like appearance. TSEs include diseases such as scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle (aka mad cow disease), chronic wasting disease in cervids and Creutzfeldt-Jakob disease in humans. These diseases affect the central nervous system and result in lesions in the brain. The causative infectious agents are modified, rogue proteins called prions. CWD infects elk, white-tailed deer, and mule deer, but is not known to naturally infect other species of wildlife (including predators and scavengers), livestock, or humans. There is no treatment for CWD and it is typically fatal. The mode of transmission of CWD is not well understood. Transmission from infected animals to uninfected animals via nose to nose contact, saliva, urine and feces are considered the likely routes. Transmission may also occur through environmental contamination. Clinical signs of the disease are not unique and are similar to those for other conditions, such as malnutrition. Infected animals may not show clinical signs of CWD for several years. Currently, diagnosis of CWD requires testing of a specific portion of the brain and spinal cord. Also, a tonsil biopsy technique has also been developed. One of the primary concerns of the USDA is the potential transmission of CWD between captive and free-ranging animals (Miller and Williams 2004) and research is underway to understand the rates and types of contacts between them. The goal is to develop cost-effective barriers and strategies to reduce or eliminate any contact along game farm fences and other areas. Studies are also investigating and comparing the density, movement, and habitat use of white-tailed deer and mule deer and how these characteristics relate to the manifestation, transmission, and spread of CWD. Data will be used in the development of models and formation of management decisions. Additional studies will look at the role of predators and scavengers in the possible transmission and or dissemination of CWD. Summary above taken from: MCLEAN, R. G., L. CLARK, M. R. DUNBAR, K. C. VERCAUTEREN, AND T. A. CAMPBELL. 2005. Wildlife disease research at the APHIS National Wildlife Research Center. Pages 123-135 in Proceedings of the One Hundred and Eighth Annual Meeting of the United States Animal Health Association. Literature CitedMILLER, M. W. AND E. S. WILLIAMS. 2004. Chronic wasting disease of cervids. Current Topics in Microbiology and Immunology 284:193-214. Chronic Wasting Disease LinksUSDA Animal and Plant Health Inspection Service USGS National Wildlife Health Center Chronic Wasting Disease Alliance Resources from Selected StatesCalifornia Colorado Michigan Minnesota Missouri Nebraska Tennessee Wisconsin Utah Wyoming |
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Content: Laurie Paulik Last updated:
02/05/08 |
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