BSE - Bovine Spongiform Excephalophathy Article
Mike Sweat, Baker County Extension Director
Bovine Spongiform Encephalopathy or BSE was found on a Washington state dairy back in December 2003, this was the first and only confirmed case in the United States. Bovine Spongiform Encephalopathy aka Mad Cow Disease is a chronic degenerative disease affecting the central nervous system of cattle, affected animals display changes in temperament such as nervousness, aggression, in coordination. BSE belongs to a family of diseases known as transmissible spongiform encephalopathies (TSE’s) which have been around for years. Other TSE’s include scrapie in sheep and goats, chronic wasting disease of deer and elk, and Creutzfeld-Jakob Disease (CJD) in humans. The disease is thought to be caused by an abnormal or altered protein called a "prion" in the brain. The disease is found almost exclusively in cattle over 2 years old. The incubation period for this disease ranges from 2-8 years and is always fatal. After the onset of the disease the animal dies within 2 weeks to 6 months. There is no vaccination available to prevent this disease. BSE testing currently is conducted only on brain tissue from slaughtered cattle.
BSE disease first appeared in Great Britain in 1986 and has since affected over 178,000 cattle worldwide. The epidemic in Great Britain apparently peaked in 1993 and has since been on the decline due to eradication efforts. It is suspected that the cause of BSE in Great Britain involved animal feed containing contaminated meat and bone meal made from sheep infected with scrapie (a similar disorder in sheep) or from cows with BSE. as a protein source. This practice has since been banned in Europe and the United States. Also imports of live cattle and cattle products have been banned from countries known to have BSE since 1989. Most cases in Great Britain have occurred in dairy cattle that were between 3 and 6 years old. Scientific evidence has found that BSE does not spread between cattle or from cattle to other animal species. The only known way to spread the disease between cattle is through consumption of animal by-products from a contaminated animal. This practice was banned in the U.S. in August of 1997.
USDA has been closely monitoring for this disease for 13 years from cattle displaying any possible symptoms of BSE and the cow in Washington was the very first to test positive. The entire herd which had the BSE positive animal in Washington State has been depopulated and tested with negative results. In addition, eight additional operations in Washington had received animals from the herd with BSE. All of these herds were tested and samples were negative for BSE.
Since January 2004, USDA has tested 20,543 animals. On March 15, 2004, Agriculture Secretary Ann Veneman announced that USDA would expand the U.S. surveillance program for BSE following the recommendations of an international scientific review panel. Additional testing labs across the country have been established and some 268,000 animals from slaughter facilities and from herds across the country will be tested each year. The sampled carcasses will be held and not allowed to enter the food chain until test results show the samples are negative. This enhanced testing program is designed to detect BSE with a 95% confidence level even if there were only five positive animals in the entire country.