ARCHIVE: BSE: Other TSEs


Human TSEs

Human TSEs include Kuru which was found in Papua New Guinea and the various forms of Creutzfeld-Jakob Disease (CJD) and related conditions.

CJD is a fatal brain disease first classified in the 1920s. In 1996, doctors reported a new variant of the disease, vCJD. Research since suggests that vCJD is the result of exposure to the agent that causes Bovine Spongiform Encephalopathy (BSE) in cattle

Animal TSEs

In addition to classical and atypical scrapie in sheep and goats and bovine spongiform encephalopathy (BSE) in cattle (and goats), TSEs have been found to occur in other species. TSE cases in domestic felines, captive exotic felines and captive exotic ruminants are believed to be linked to BSE.

In November 1994, the laboratory diagnosis of a spongiform encephalopathy in any species became notifiable. Since July 2001, the EU TSE Regulation (999/2001) has required any animal suspected of being affected with a TSE to be reported to the competent authorities.

Transmissible Mink Encephalopathy (TME)

TME is a very rare fatal neurological disease of farmed mink which was first recognised in the USA in 1947. TME has been largely confined to the United States of America (USA), although incidents have also occurred in Canada, Finland, Germany and Russia. The last reported outbreak was in Wisconsin, USA in 1985.

TME takes the form of a rapidly evolving epidemic, usually involving a single mink farm. Clinical signs include behavioural changes followed by neurological signs including hyper-excitability, incoordination progressing to circling, somnolence, debilitation and death.

TME is believed to be feed borne, associated with the consumption of the infectious agent in contaminated meat. One experimental study noted similarities between TME and atypical (L-type) BSE in a mouse model. This is consistent with epidemiological studies into the 1985 outbreak which suggested a bovine origin, as mink were fed cattle but not sheep remains. L-type BSE has not yet been reported in the USA.

References:

Baron, T., Bencsik, A., Biacabe, A-G., Morignat, E., and Bessen, R. A. (2007) Phenotypic similarity of transmissible mink encephalopathy in cattle and L-type bovine spongiform encephalopathy in a mouse model. Emerging Infectious Diseases, Vol. 13, No. 12, December 2007, pages 1887-189

Marsh R. F and Hadlow. W. J. 1992. Transmissible mink encephalopathy. Rev.sci.tech. Off. int. Epiz. 11 (2). 539-550.

United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS)

Williams, E.S. and Miller, M.W. (2003) Transmissible spongiform encephalopathies in non-domestic species: origin, transmission and risk factors. Rev.sci.tech Off.int.Epiz. 22(1).145-156

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Chronic Wasting Disease (CWD)

CWD is a disease of Rocky Mountain Elk (Cervus elaphus nelsoni), Mule deer (Odocoileus hemionus), Black-Tailed Deer (Odocoileus hemionus), White-Tailed Deer (Odocoileus virginianus) and Moose (Alces alces). Because Red Deer (Cervus elaphus elaphus) are genetically very similar to Rocky Mountain Elk, it is likely that they are also susceptible to CWD.

The prevalence and geographical distribution of CWD in these species appears to be increasing in North America. Cases of CWD have also been reported in the Republic of Korea although these are probably linked to elk exported from Canada.

The origin of CWD is unknown and the disease transmits in the absence of contaminated feed. The precise mechanism of transmission is unclear. It is possible that the infectious agent is shed in the saliva, faeces or urine or as a result of decomposition of infected carcases and transferred to other cervids grazing the contaminated areas. It is also possible that some maternal transmission occurs.

The disease is characterised by behavioural changes, excessive salivation, incoordination and weight loss typically over a period of weeks or months, followed by death.

In January 2007, the EU agreed a time-limited active surveillance programme for TSEs in wild and farmed red deer. The Communications Strategy (PDF 21 KB) provides further details.

  • References:

Williams E. S and Young. S. 1992. Spongiform encephalopathies in Cervidae. Rev.sci.tech. Off. int. Epiz. 11 (2). 551-567

Spraker T. R. et al 1997. Spongiform encephalopathy in free-ranging mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginianus) and Rocky Mountain elk (cervus elaphus nelsoni) in Northcentral Colorado. Journal of Wildlife Diseases. 33 (1). 1-6.

Williams, E.S. and Miller, M.W. (2003) Transmissible spongiform encephalopathies in non-domestic species: origin, transmission and risk factors. Rev.sci.tech Off.int.Epiz. 22(1).145-156

EFSA (2004) Opinion of the European Food Safety Authority on a surveillance programme for Chronic Wasting Disease in the European Union

Defra (2004) Transmissible spongiform encephalopathies (TSEs) in Deer – Advisory Notes for Farmers

SEAC (2006) Position Statement - on Chronic Wasting Disease in UK deer

United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS)

Canadian Food Inspection Agency (CFIA)l

Chronic Wasting Disease Alliance

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Feline Spongiform Encephalopathy (FSE)

FSE was first identified in the UK in 1990. Most cases have been reported in the UK, where the epidemic has been consistent with that of the BSE epidemic. Some other countries (e.g. Norway, Liechtenstein and France) have also reported cases.

Most cases have been reported in domestic cats but there have also been cases in captive exotic cats (e.g. Cheetah, Lion, Asian leopard cat, Ocelot, Puma and Tiger). The disease is characterised by progressive nervous signs, including ataxia, hyper-reactivity and behavioural changes and is fatal.

The chemical and biological properties of the infectious agent are identical to those of the BSE and vCJD agents. These findings support the hypothesis that the FSE epidemic resulted from the consumption of food contaminated with the BSE agent.

The FSE epidemic has declined as a result of tight controls on the disposal of specified risk material and other animal by-products.

  • References:

Leggett, M.M. et al.(1990) A spongiform encephalopathy in a cat. Veterinary Record. 127. 586-588

Synge, B.A. et al. (1991) Spongiform encephalopathy in a Scottish cat. Veterinary Record. 129. 320

Wyatt, J. M. et al. (1991) Naturally occurring scrapie-like spongiform encephalopathy in five domestic cats. Veterinary Record. 129. 233.

Gruffydd-Jones, T. J.et al.. (1991) Feline spongiform encephalopathy. J. Small Animal Practice. 33. 471-476.

Pearson, G. R. et al. (1992) Feline spongiform encephalopathy: fibril and PrP studies. Veterinary Record. 131. 307-310.

Willoughby, K. et al. (1992) Spongiform encephalopathy in a captive puma (Felis concolor). Veterinary Record. 131. 431-434.

Fraser, H. et al. (1994) Transmission of feline spongiform encephalopathy to mice. Veterinary Record 134. 449.

Bratberg, B. et al. (1995) Feline spongiform encephalopathy in a cat in Norway. Veterinary Record 136. 444

Baron, T. et al. (1997) Spongiform encephalopathy in an imported cheetah in France. Veterinary Record 141. 270-271

Zanusso, G et al. (1998) Simultaneous occurrence of spongiform encephalopathy in a man and his cat in Italy. Lancet, V352, N9134, OCT 3, Pp 1116-1117.

Ryder, S.J. et al. (2001) Inconsistent detection of PrP in extraneural tissues of cats with feline spongiform encephalopathy. Veterinary Record 146. 437-441

Kelly, D.F. et al. (2005) Neuropathological findings in cats with clinically suspect but histologically unconfirmed feline spongiform encephalopathy. Veterinary Record 156. 472-477.

TSEs in Exotic Ruminants

TSEs have been detected in exotic ruminants in UK zoos since 1986. These include antelopes (Eland, Gemsbok, Arabian and Scimitar oryx, Nyala and Kudu), Ankole cattle and Bison. With hindsight the 1986 case in a Nyala was diagnosed before the first case of BSE was identified. The TSE cases in exotic ruminants had a younger onset age and a shorter clinical duration compared to that in cattle with BSE. All the cases appear to be linked to the BSE epidemic via the consumption of feed contaminated with the BSE agent. The epidemic has declined as a result of tight controls on feeding mammalian meat and bone meal to susceptible animals, particularly from August 1996.

  • References:

Jeffrey, M. and Wells, G.A.H, (1988) Spongiform encephalopathy in a nyala (Tragelaphus angasi). Vet.Path. 25. 398-399

Kirkwood, J.K. et al (1990) Spongiform encephalopathy in an Arabian oryx (Oryx leucoryx) and a Greater kudu (Tragelaphus strepsiceros) Veterinary Record 127. 418-429.

Kirkwood, J.K. (1993) Spongiform encephalopathy in a herd of Greater kudu (Tragelaphus strepsiceros): epidemiological observations. Veterinary Record 133. 360-364

Kirkwood, J. K. and Cunningham, A.A. (1994) Epidemiological observations on spongiform encephalopathies in captive wild animals in the British Isles. Veterinary Record. 135. 296-303.

Food and Agriculture Organisation (1998) Manual on Bovine Spongiform Encephalopathy.

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Page last modified: 28 October, 2009
Page last reviewed: 11 November, 2009