One of the deadliest diseases health-care workers fight today, tuberculosis (often called TB) infects the lungs of one-third of the world's population and kills about 2 million people a year. While scientific breakthroughs brought this bacterial disease under control during the 1960s to the 1980s, it was never completely eliminated. In the early 1990s, TB came back as a serious global threat. Not only has TB spread to virtually every country on earth,...