Bovine spongiform encephalopathy (BSE) is a slowly progressing fatal disease affecting the central nervous system of cattle. The disease was first diagnosed in Great Britain in 1986 and belongs to a family of disease known Bovine as transmissible spongiform encephalopathies (TSE's). A number of diseases of animals including scrapie, chronic Spongiform wasting disease, and transmissible mink encephalopathy; as well as the human diseases, Creutzfeld-Jacob disease, kuru, and Gerstmann-Straussler-Scheinker syndrome are Encephalopathy other example of TSE's. The causative agent of these Gerald L. Stokka, DVM, MS TSE's is an incompletely characterized infectious agent Extension Beef Cattle Veterinarian known as an unconventional virus or prion. BSE Epidemic Clinical Signs Jeremy Van Boening, BS Since 1986, approximately Affected animals may 176,000 cases of BSE have display changes in tempera- occurred among nearly 34,000 ment, such as nervousness or herds mostly in the United aggression, abnormal posture, Kingdom (UK). The epidemic incoordination, difficulty in peaked in January 1993 with rising, and decreased milk nearly 1,000 new cases production despite continued reported weekly. Approxi- appetite. Initial clinical signs mately two-thirds of the dairy may be quite subtle and herds in the UK have had at mainly behavioral in nature. least one case of BSE, while The signs progress over weeks only one in six beef herds to months with the animals have reported cases. The condition deteriorating from outbreaks in the UK are 2 to 6 months and most believed to have resulted from reaching a terminal state by the feeding of scrapie-contain- 3 months. Upon clinical ing sheep meat-and-bone diagnosis with some certainty, meal. Accordingly, there is euthanasia is advisable as general agreement that the animals may become unman- outbreak was increased by ageable and their welfare is at feeding bovine meat-and- risk. bone meal to young calves. Subsequently, in July 1988, Diagnosis ruminant protein in ruminant There is no reliable test to feed was banned. The ban detect the disease in live significantly diminished the animals. Microscopic exami- incidence of new clinical cases nation of brain tissue at in five years, which is the necropsy is the primary incubation period of the laboratory method used to disease. However, approxi- confirm a diagnosis of bovine mately 36,000 new cases have spongiform encephalopathy. been diagnosed since the ban, Also, immunohistochemistry which indicates the ban was and immunoblotting are used not totally effective. Conse- to detect the disease agent. quently, a ban from feeding any mammalian protein to PREVENTION Kansas State University any farm animal species was There has not been one Agricultural Experiment Station and implemented in the United reported case of BSE in native Cooperative Extension Service Kingdom in 1996. The cattle in North America, number of new cases contin- although Canada has one ues to decline at a steady rate. confirmed case of an infected

1 cow imported from Great of Health, and the Food Safety and 161, BSE is a reportable Britain. Because treatment of and Inspection Service. disease by accredited veteri- BSE has proved ineffective, Restrictions began in 1989 narians. The USDA has the infected cow was de- with the banning of importa- trained more than 250 state stroyed as well as all herd tion of ruminants, bovine and federal veterinarians mates and any animals that serum, embryos, and meat- located throughout the United were determined at risk. and-bone meal from the States in the recognition of Many countries and United Kingdom. Surveil- BSE. Any person or veterinar- governmental agencies have lance began in 1990 with a ian suspecting an animal of implemented programs to program including histologi- BSE should report the animal slow and prevent the spread cal examination of brain tissue immediately to the nearest of the disease. The United of high risk cattle, and the diagnostic laboratory and the States Department of Agricul- traceback of cattle imported state veterinarian. ture (USDA) has formed a from the UK. Accordingly, on proactive and preventive August 4, 1997, the FDA policy, which has taken established guidelines that Further Reading measures in surveillance, prohibit the feeding of most Center for Disease Control prevention, education, and mammalian proteins to http://www.cdc.gov/ response. The Animal Plant ruminants. As of December Health Inspection Service 1997, APHIS has prohibited European Government (APHIS) has created a TSE the importation of live http://www.maff.goc.uk/ working group to analyze ruminants and most ruminant animal/bse risks to the United States and products from Europe until a is sharing information with thorough assessment of the Food and Drug Adminis- the Center for Disease Con- risk is made. tration trol, Food and Drug Adminis- Under title 9 code of http://www.fda.gov/cvm tration, the National Institute federal regulations, parts 71

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Publications from Kansas State University are available on the World Wide Web at: http://www.oznet.ksu.edu Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, credit Stokka et al., Bovine Spongiform Encephalopathy, Kansas State University, January 2000.

Kansas State University Agricultural Experiment Station and Cooperative Extension Service MF-2434 January 2000 It is the policy of Kansas State University Agricultural Experiment Station and Cooperative Extension Service that all persons shall have equal opportunity and access to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age or disability. Kansas State University is an equal opportunity organization. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended. Kansas State University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Marc A. Johnson, Director.

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