Beware of opening unmarked boxes because they may be filed with history's most deadly diseases. A scientist cleaning out a storage room in a National Institutes of Health building in Maryland discovered vials of freeze-dried smallpox virus from the 1950s—the first time an unaccounted for sample has been discovered. (The vials were intact and sealed.) Smallpox was declared to be eradicated in the 1980s, and the only known samples are under heavy security in Atlanta—where the samples have now been transferred—and Russia. "We don't yet know if it's live and infectious," an official at the Centers for Disease Control director said.