Mad Cow Disease (Spongiform Encephalopathy or BSE)
Mad cow disease, or bovine spongiform encephalopathy (BSE), is a disease that was
first found in cattle. It's related to a disease in humans called variant Creutzfeldt-Jakob
disease (vCJD). Both disorders are universally fatal brain diseases caused by a prion.
A prion is a protein particle that lacks DNA (nucleic acid). It's believed to be the
cause of various infectious diseases of the nervous system. Eating infected cattle
products, including beef, can cause a human to develop mad cow disease.
What is mad cow disease?
Mad cow disease is a progressive, fatal neurological disorder of cattle resulting
from infection by a prion. It appears to be caused by contaminated cattle feed that
contains the prion agent. Most mad cow disease has happened in cattle in the United
Kingdom (U.K.), a few cases were found in cattle in the U.S. between 2003 and 2006.
Feed regulations were then tightened.
In addition to the cases of mad cow reported in the U.K. (78% of all cases were reported
there) and the U.S., cases have also been reported in other countries, including France,
Spain, Netherlands, Portugal, Ireland, Italy, Japan, Saudi Arabia, and Canada. Public
health control measures have been implemented in many of the countries to prevent
potentially infected tissues from entering the human food chain. These preventative
measures appear to have been effective.
What is variant Creutzfeldt-Jakob Disease (vCJD)?
Creutzfeldt-Jakob Disease (CJD) is a rare, fatal brain disorder. It causes a rapid,
progressive dementia (deterioration of mental functions), as well as associated neuromuscular
disturbances. The disease, which in some ways resembles mad cow disease, traditionally
has affected men and women between the ages of 50 and 75. The variant form, however,
affects younger people (the average age of onset is 28) and has observed features
that are not typical as compared with CJD. About 230 people with vCJD have been identified
since 1996. Most are from the U.K. and other countries in Europe. It's rare in the
What is the current risk of getting vCJD from eating beef and beef products from cattle
Currently this risk appears to be very small, perhaps fewer than 1 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. Solid pieces of beef are less likely to be contaminated with tissues that
may hide the mad cow agent. Milk and milk products are not believed to transmit the mad
cow agent. You can't get vCJD or CJD by direct contact with a person who has the disease.
A few cases were acquired during transfusion of blood from an infected donor. Most
human Creutzfeldt-Jakob disease is not vCJD and is not related to beef consumption
but is also likely due to prion proteins