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Health Update: Bovine Spongiform Encephalopathy "Mad Cow Disease"
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Health Update: Bovine Spongiform Encephalopathy "Mad Cow Disease"
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Health Update: provides updated information regarding an incident or situation; unlikely to require immediate action.
Recently, the first case of bovine spongiform encephalopathy (BSE or commonly known as “mad cow disease”) has been identified in the U.S. BSE, along with several other diseases, belong to a family of diseases call “transmissible spongiform encephalopathies” (TSEs). TSEs are believed to be caused by aberrant proteins called prions. TSEs are characterized by spongy degeneration of the brain with severe and fatal neurological signs and symptoms. TSEs include: scrapie in sheep and goats, BSE in cattle, chronic wasting disease (CWD) in deer and elk, and Creutzfeldt-Jakob disease (CJD) or the newly recognized variant CJD (vCJD) in humans.
At this time, there are no confirmed cases of CJD or vCJD in Lucas County. CJD is a reportable disease in Ohio and any suspect or confirmed case is required to be reported to the local and state health department.
Bovine spongiform encephalopathy (BSE)
BSE (widely known as "mad cow disease") is a transmissible, neurodegenerative, fatal brain disease of cattle. The disease has a long incubation period of four to five years, but ultimately is fatal for cattle within weeks to months of its onset.
On the morning of December 25, the BSE world reference lab in Weybridge, England, confirmed the U.S. Department of Agriculture’s (USDA) December 23 preliminary diagnosis of BSE in a single nonambulatory dairy cow that had been slaughtered on December 9 at Vern's Moses Lake Meats in Washington State. The beef products were distributed from Verns Moses Lake to Midway Meats on December 11. The vast majority of these products, at least 80 percent, were distributed to stores exclusively in the states of Oregon and Wisconsin. All of the central nervous system related tissue, brain, spinal cord and distal ileum were removed at the Verns facility during the slaughter that occurred on December 9, 2003. These are the tissues most likely to contain the BSE agent. Because the meat leaving Verns did not contain these high risk materials, the recalled beef presents an essentially zero risk to consumers. At the time of USDA's preliminary diagnosis on December 23, USDA's Food Safety and Inspection Service (FSIS) issued a Class II recall for the facility's entire day's production. The recall was classified as Class II due to the extremely low likelihood that the beef being recalled contains the infectious agent that causes BSE.
USDA continues to work with the Canadian officials to verify traceback of the index animal. Records obtained from the owner correspond with Canada’s records indicating that this animal was approximately 6-1/2 years old at the time of slaughter. The age of the animal is significant. She would have been born before feed bans were implemented in North America in August 1997. The feed bans prohibit the inclusion of cattle protein in feed intended for other cattle to eat, a practice that has been identified as the primary means by which BSE spread between cattle.
Epidemiologic data suggest BSE is probably transmitted by feeding cattle animal feed containing contaminated meat and bone meal as a protein meat source. There is no evidence that BSE spreads by contact between unrelated adult cattle or contact between cattle and other species. Limited research suggests that maternal transmission (passed from mother to calf) may occur at a very low level. It is important to note that BSE is not communicable diseases—it does not spread easily like viruses.
Food Safety
The scientific community believes that there is no evidence to demonstrate that muscle cuts or whole muscle meats that come from animals infected with BSE are at risk of harboring the causative agent of the disease. To date, there has been no evidence of BSE infection detected in milk or muscle tissue.
Ohio has been part of a federal-state partnership for many years to develop regulatory “firewalls” to protect against the introduction and spread of BSE. In Ohio, state and federal meat inspectors collect hundreds of bovine animal tissue samples each year for testing at the federal lab in Ames, Iowa. Ohio sent 555 brain tissue samples in federal fiscal year 2003. All tests have been negative for BSE.
Although the risk of ingesting products infected with BSE in the U.S. is low, people should use the following common-sense precautions to decide what is safe to eat.
- Muscle meat from cattle is safe – it is not considered by scientists to be a risk for transmitting BSE.
- Milk and milk products from cows are safe – they are not considered by scientists to be a risk for transmitting BSE.
- People should avoid consuming cattle brains and spinal cord tissue.
- No individual should slaughter or consume any animal that appears diseased.
BSE is a disease that affects cattle. However, there is a disease similar to BSE called variant Creutzfeldt-Jakob disease (CJD), or vCJD, which is found in humans. There have been a small number of cases of this newly recognized variant of CJD, primarily in the United Kingdom, occurring in people who consumed beef that may have been contaminated. More information on CJD can be found below.
Creutzfeldt-Jakob Disease (CJD)
CJD is a rare, fatal brain disorder in humans, which causes a rapid, progressive dementia and associated neuromuscular disturbances. CDJ affects about one person in every one million people per year worldwide. In the United States there are about 200 cases per year. CJD usually appears in later life and runs a rapid course. CJD occurs in a form associated with a hereditary predisposition (approximately 5–10% of all cases) and in a more common (or sporadic) form that accounts for 85–90% of cases.
A newly recognized form of CJD, variant Creutzfeldt-Jakob disease (vCJD), was first reported in March 1996 in the UK. In contrast to the classical forms of CJD, vCJD has affected younger patients (average age 29 years, as opposed to 65 years), has a relatively longer duration of illness (median of 14 months as opposed to 4.5 months) and is strongly linked to exposure to BSE (probably through food). Although specific foods that transmit the BSE agent to humans have not been identified, transmission is believed to occur primarily by processed food items that contain infectious bovine tissues such as the brain or spinal cord.
In the United Kingdom, where over 1 million cattle may have been infected with BSE, a substantial species barrier appears to protect humans from widespread illness. As of December 1, 2003, a total of 153 vCJD cases had been reported worldwide; of these, 143 cases had occurred in the United Kingdom. In 2002, one probable vCJD case was identified in a U.S. resident in Florida. Overall, the risk to human health from BSE in the United States is extremely low.
The one probable U.S. vCJD case grew up in the United Kingdom when the BSE outbreak was increasing and when the risk for human exposures to BSE was probably at its peak. Therefore, it is likely that this person was exposed to the BSE agent one or more times prior to moving to the U.S.
Where can I find additional information?
- For additional information on BSE and CJD, contact the Toledo-Lucas County Health Department at (419) 213-4218 or visit our website at www.lucascountyhealth.com. Go to the Environmental Health section.
- Additional information on BSE can be found at the following websites:
- Additional information on CJD can be found at the following websites:
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