Amusement & Music Operators Association
BSE in an Alabama cow (March 15, 2006)—On March 13, 2006, the U.S. Department of Agriculture (USDA) announced the confirmation of bovine spongiform encephalopathy (BSE) in a cow in Alabama. This is the eighth confirmed case of BSE in North American cattle and the second case since the beginning of 2006.
BSE (bovine spongiform encephalopathy) is a progressive neurological disorder of cattle that results from infection by an unconventional transmissible agent termed a prion. The nature of the transmissible agent is not well understood. Currently, the most accepted theory is that the agent is a modifi ed form of a normal cell surface component known as prion protein. The pathogenic form of the protein is both less soluble and more resistant to enzyme degradation than the normal form.
Research indicates that the fi rst probable infections of BSE in cows occurred during the 1970s with two cases of BSE being identifi ed in 1986. BSE possibly originated as a result of the feeding of scrapie-containing sheep meat-and-bone meal to cattle. There is strong evidence and general agreement that the outbreak was amplified and spread throughout the UK cattle industry by feeding rendered bovine meat-and-bone meal to young calves.
The BSE epidemic in the United Kingdom peaked in January 1993 at almost 1,000 new cases per week. Through the end of April 2005, more than 184,000 cases of BSE had been confi rmed in the United Kingdom alone in more than 35,000 herds.
There has since emerged strong epidemiologic and laboratory evidence for a causal association between variant CJD in humans and the BSE outbreak in cattle. The interval between the most likely period for the initial extended exposure of the population to potentially BSE-contaminated food (1984-1986) and the onset of initial variant CJD cases (1994-1996) is consistent with known incubation periods for the human forms of the disease.
On June 24, 2005, the U.S. Department of Agriculture announced receipt of final results from The Veterinary Laboratories Agency in Weybridge, England, confi rming BSE in a cow that had conflicting test results in 2004. No parts of the animal entered the human and animal food supply. As a result of this BSE positive animal, the USDA plans to develop a new laboratory testing protocol to evaluate future inconclusive BSE screening test results.
The only other 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 identifi cation number suggested that the BSE-infected cow was imported into the United States from Canada in August 2001. This information was later confi rmed by genetic testing.
On January 2 and 11, 2005, the Canadian Food Inspection Agency (CFIA) announced the confirmation of BSE in two cows from the province of Alberta. One of the cows was born in October 1996 and the second cow was born in March 1998, after the Canadian government instituted a ruminant feed ban in 1997. No part of these animals has entered the human food supply, according to CFIA.
These two BSE-positive cows bring the total number of BSE-infected cows identified in or linked to Canada to four, including a BSE-positive cow identifi ed in Washington State that was later determined to have originated from Alberta. CDC is in communication with the U.S. Department of Agriculture and will continue to monitor these developments closely. More updated information on the BSE situation in Canada is available from the CFIA BSE website.
Current USDA BSE information and testing results are available on the Animal Plant and Health Inspection Service BSE site at the USDA.
Regularly updated numbers of reported BSE cases, by country, are available on the Offi ce International Des Epizooties (OIE) BSE website.
The U.S. public health system and primary healthcare providers must be prepared to address various biological agents, including pathogens that are rarely seen in the United States. High-priority agents include organisms that pose a risk to national security because they
Second highest priority agents include those that
Third highest priority agents include emerging pathogens that could be engineered for mass dissemination in the future because of