Mad Cow Disease - Case Study Example

(see figure below). Preliminary information indicates that this most recent BSE case occurred in a13 year old beef cow from Alberta. Thus, this animal was born before the implementation of Canada's 1997 feed ban," Further elaborating that, "Through 2007, BSE surveillance has identified 15 cases in North America: three BSE cases in the United States and 12 in Canada. Of the three cases identified in the United States, one was born in Canada; of the 12 cases identified in Canada, one was imported from the United Kingdom (see figure above).

Assuming that the proportions of animals sampled that were found to have BSE similarly reflect each country's BSE prevalence, the surveillance data indicate that the prevalence of BSE in Canada is well over 20-fold higher than that in the United States (see BSE Prevalence below). (CDC p.1). The following is a graph obtained from the CDC's webpage of those impacted within North America. The first known case of BSE in the United States was identified in December 2003. On December 23, 2003, the U.S. Department of Agriculture (USDA) announced a presumptive diagnosis of BSE in an adult Holstein cow from Washington State.

This diagnosis was confirmed by an international reference laboratory in Weybridge, England, on December 25. Preliminary trace-back based on an ear-tag identification number suggested that the BSE-infected cow was imported into the United States from Canada in August 2001. The preliminary trace-back identification of the animal was later confirmed by genetic testing.On June 24, 2005, the U.S. Department of Agriculture announced receipt of final results from The Veterinary Laboratories Agency in Weybridge, England, confirming BSE in a cow that had conflicting test results in 2004.

This cow was from Texas and represented the first endemic case of BSE in the United States.On March 13, 2006, the U.S. Department of Agriculture (USDA) announced the confirmation of bovine spongiform encephalopathy (BSE) in a cow in Alabama. The newly confirmed case was identified in a non-ambulatory (downer) cow on a farm in Alabama. The animal was euthanized by a local veterinarian and buried on the farm. The age of the cow was estimated by examination of the dentition as 10-years-old. It had no ear tags or distinctive marks; the herd of origin could not be identified despite an intense investigation (see Alabama BSE Investigation, Final Epidemiology Report, May 2006 [PDF - 105 KB]).(CDC p.1).

History (B) "Mad cow disease spread widely among the cattle herds of England in the 1990's because cows were fed bone meal prepared from cattle carcasses to increase the protein content of their diet. Like the Fore, the British cattle were literally eating the tissue of cattle that had died of the disease," (Johnson p.677). Even earlier than that, "Research indicates that the first probable infections of BSE in cows occurred during the 1970's with two cases of BSE being identified in 1986. BSE possibly originated as a result of feeding cattle meat-and-bone meal that contained scrapie-infected sheep products.

Scrapie is a prion disease of sheep. There is strong evidence and general agreement