Mad cow disease has been back in the spotlight, following the USDA's seizure of a flock of sheep in Vermont last month. Some of those sheep had tested positive for scrapie, a disease similar to mad cow disease. Mad cow disease first surfaced in Great Britain in 1986. It is believed to have originated from contaminated cattle feed made from ground up infected animal carcasses. In 1996, the first cases of the human form of mad cow disease were reported in Great Britain.
Scientists believe the disease is spread in humans after they consume contaminated cattle products.
There is no test for the disease and it often is fatal, since there is no known treatment or cure. The only conclusive diagnosis is made during a brain autopsy. Pages will open in a new browser window External sites are not endorsed by CNN Interactive. An AOL Time Warner Company. All Rights Reserved.