11.   Public health officials and agricultural experts say there are good reasons to believe that mad cow disease will not become a problem in the United States.

12.   That all changed in November, when mad cow disease became a Europe-wide phenomenon.

13.   The disease becomes increasingly common with advancing years and has become a major public health problem as more people live longer.

14.   Volberding said delayed treatment can lead to earlier death because the disease becomes harder to treat once it develops into full-blown AIDS and the immune system starts breaking down.

15.   When Harvard biologists William F. Dietrich and John Collier dedicated their careers to anthrax research, the possibility that the disease would become a terrorist weapon seemed remote.

16.   Al-Zaeen said both diseases had become epidemics, the Sudanese daily newspaper, Al-Sudan Al-Hadith, reported Wednesday.

17.   Disease has become a growing threat from the rotting carcasses of millions of hogs, chickens and turkeys.

18.   Does the disease become more lethal as it is passed from person to person to person?

19.   Does the disease become more lethal as it is passed from person to person?

20.   Firewood and clean water became scarce, and diseases became more common.