In this episode of Science in Action, we find out that tuberculosis (TB) is the leading cause of death in South Africa. After visiting a clinic dedicated to the diagnosis and treatment of TB, Roland Pease meets researcher Professor Grant Theron at Stellenbosch University, who explains why the disease is still so prevalent. Next we hear from Professor Novel Chegou and his student Candice Snyders, also based at Stellenbosch University. They are researching biomarkers to diagnose tuberculosis and have already successfully developed a rapid finger-prick test to identify TB. Roland then chats to vaccine researcher Professor Thomas Scriba at the University of Cape Town, who reveals more about the current landscape of TB vaccination. Presenter: Roland Pease Producer: Ella Hubber Editor: Martin Smith Production co-ordinator: Jana Bennett-Holesworth (Photo: Frontline healthcare workers wear a protective mask and tb mask to prevent the spread of airborne disease. Credit: stockstudioX/Getty Images)