SUMMARY: Sunday marked World Tuberculosis Day. While T.B. doesn’t attract the same attention as influenza, malaria, or Ebola, it recently surpassed HIV/AIDS to become the globe's leading infectious killer. In 2018, there were more than 10 million new cases. There hadn’t been a treatment breakthrough for 40 years, but the tide is starting to turn. Hari Sreenivasan shares a story of hope from South Africa.