11.   Although the Agriculture Department tries to test downer cows for signs of mad cow disease, it can only sample a small percentage.

12.   Among other things, drug-producing animals will have to be certified as free of mad cow disease or other serious infectious illnesses.

13.   Although the consensus holds that an arrival in America is unlikely soon, scientists insist that keeping mad cow disease at bay demands vigilance.

14.   Among the issues are the traceability of cattle, increased testing for mad cow disease and meat labeling.

15.   Although there has never been a case of mad cow disease reported in Italy, the Agriculture Department instituted the ban after identifying substantial risk factors.

16.   An unknown number of American sheep are infected with scrapie, which, like mad cow disease, is a spongiform encephalopathy.

17.   And most are not tested for mad cow disease unless there were symptoms of such maladies.

18.   Animals infected with mad cow disease have been destroyed, so meat supplies are limited.

19.   Another, called new variant CJD, is acquired by eating the nervous tissues of cattle infected with mad cow disease.

20.   Argentina is hoping its ad campaign will convince Europeans worried about mad cow disease to buy Argentine beef.