BSE ("Mad Cow Disease") and nvCJD
"Mad Cow Disease" actually refers to bovine spongiform encephalopathy (BSE), a disease in cattle which is related to a disease in humans called new variant Creutzfeldt-Jakob disease (nvCJD). Both disorders are fatal brain diseases caused by a prion - a protein particle that lacks nucleic acid and is believed to be the cause of various infectious diseases of the nervous system. It is believed that the agent that causes human deaths from nvCJD is the same agent that causes outbreaks of BSE in cattle. However, scientists have been unable to determine the specific foods, if any, that are responsible for transmitting the disease from cattle to humans.
What is bovine spongiform encephalopathy (Mad Cow Disease)?
BSE is a progressive neurological disorder of cattle resulting from infection by an unconventional transmissible agent. From 1995 through June 2002, 124 human case of vCJD were reported in the United Kingdom and six in France.
In addition to the cases of BSE reported in the United Kingdom (99 percent of all cases were reported there), cases have also been reported in other European countries, including Belgium, France, Liechtenstein, Luxembourg, Netherlands, Portugal, Ireland, Italy, and Switzerland. Public health control measures have been implemented in each country of Europe to prevent potentially BSE-infected tissues from entering the human food chain. These preventative measures appear to have been effective. Other countries reporting a rare number of cases of BSE inlcude Japan, Greece, and Finland.
In 2003, the US Department of Agriculture discovered a case of BSE in the US, and since this time the agency has been working with other federal agencies to minimize the risk for human exposure to BSE in the US.
What is new variant Creutzfeldt-Jakob Disease (nvCJD)?
Creutzfeldt-Jakob Disease (CJD) is a rare, fatal, brain disorder that causes a rapid, progressive dementia (deterioration of mental functions) as well as associated neuromuscular disturbances. The disease, which, in some ways resembles BSE, traditionally has affected men and women between the ages of 50 and 75 years. The "new variant" form, however, present in Great Britain, affects younger persons (the median age of onset is 28 years) and has atypical clinical features as compared to CJD. There is some epidemiological and laboratory evidence to suggest an association between BSE and nvCJD, particularly because of the absence of confirmed cases of new variant CJD in other geographic regions free of BSE.
What is the current risk of acquiring nvCJD from eating beef and beef products produced from cattle in Europe?
Currently this risk appears to be very small - perhaps fewer than one case per 10 billion servings - if the risk exists at all. Travelers to Europe who are concerned about reducing any risk of exposure can avoid beef and beef products altogether, or can select beef or beef products, such as solid pieces of muscle meat, as opposed to ground beef and sausages. The solid pieces of beef have a reduced opportunity for contamination.