After the discovery in 2003, 53 countries banned American cattle.

There are reasons to believe that mad cow disease has already risen spontaneously in American cattle, he said.

Since the single case of mad cow disease was announced last week, more than 30 nations have banned imports of American cattle.

The cow disease has not been detected in American cattle, he said.

At the same time, we have no evidence that American cattle have ever caused this disease in humans.

A large number of feed manufacturers are violating rules designed to keep mad cow out of American cattle, they said.

At least 30 million American cattle are slaughtered each year.

The number of American cattle kept in confined feedlot conditions fluctuates.

It is allowing boneless beef from American cattle under 30 months old.

But testing American cattle for dangerous pathogens will increase the cost of beef by just pennies per pound.