Million-dollar stud bulls are at risk. Some say it can live up to five days in a person's nose. On March 13, the U.S. Dept. of Agriculture banned European fresh meat and meat products. But cured meats like prosciutto are allowed. Symptoms range from loss of balance and motor control to mood changes, inability to swallow and death.
Some scientists doubt the prion theory.
She believes mad cow disease is caused by an as yet unidentified virus. However, the problem and its evolution remain shrouded in uncertainty. The first cattle cases occurred in 1984. The U.S. banned imports of ruminants and products from countries with mad cow in 1989, and from all European countries in 1997. The Food and Drug Administration also banned all ruminant-containing feed in 1997.