Pain, pus and poison.

Michael Mosley tells the extraordinary story of how scientists learnt to use the world around us to conquer the common afflictions of pain, pus and poison. In the second of three programmes, Mosley explores our earliest attempts to tackle infection and reveals the moment we began to harness the power of microbes to fight back. Mosely visits the Centre for Disease Control and Prevention (CDC) in Atlanta where the smallpox virus is incarcerated. The origins of germ theory began in the French wine industry; chemist Louis Pasteur discovered the presence of microbes in spoiled wine and developed a technique – pasteurisation – to prevent the issue. Pasteur theorised that microbes might also cause disease; an idea that German contemporary Robert Koch attempted to prove. By studying the blood of animals infected with anthrax Koch discovered that bacterial spores were to blame. Mosely visits the Frankfurt laboratory of Paul Ehrlich where, in the 1870s, the scientist used artificial dyes to selectively stain bacteria. Ehrlich postulated that if microbes could be selectively stained, they could also be selectively killed, using (in his terms) a ‘magic bullet’. Through a methodical screening process he discovered Salvarsan, the first effective treatment for syphilis. Before penicillin, doctors tried to control infection by draining pus, but half of those admitted to septic wards died. Mosley recalls Fleming’s accidental discovery of penicillin in 1928. Eric Sidebottom points out that little was made of the finding until ten years later when Oxford researchers Howard Florey, Ernst Chain and Norman Heatley extracted and tested the drug. The next challenge was to produce enough of it for use in WWII. In 1941 Florey and Heatley took the moulds to America. Mosely travels to New York to learn more about the advances that made mass production possible, revolutionising the treatment of infections. But antibiotics were useless against viruses. One of the most virulent is smallpox, which killed approximately 30% of its victims. We hear the story of Edward Jenner’s development of a vaccine and learn how immunisation works. In 1956 the World Health Organisation set up a unit with the aim of eradicating smallpox within ten years. The team was headed by epidemiologist Donald Henderson who discusses the success of the project. Today, two labs in the world are authorised to retain the smallpox virus for research, but Henderson believes the risks of keeping it outweigh the benefits. Commentators including Walter Sneader, Thomas Frieden of the CDC discuss the impact of vaccines. Mosely concludes that despite the successes, increases in population put us at a greater risk of pandemic than ever before.