31.   Once the world has been declared free of polio, experts must then decide how and when to stop vaccinating children.

32.   Public health authorities have gradually been allowing products back on the market as farms are declared free of contamination.

33.   Scotland was declared free of foot-and-mouth disease Tuesday, more than six months after the first case was confirmed.

34.   St. Thomas and St. John have been declared free of the Africanized bees, which have been known to sting people to death.

35.   The country has now been declared free of the disease.

36.   The country was declared free of the disease at the end of last year.

37.   The county of Devon, one of the areas hardest hit by the foot-and-mouth epidemic, was officially declared free of the disease Monday.

38.   The decision came days after the country was declared free of foot-and-mouth disease.

39.   The unidentified soldiers, members of an engineering battalion, were inspecting a field that had been declared free of mines, U.S. military spokesmen said.

40.   Two years later, after intense verification, the world was declared free of the disease.