A deadly new form of haemorrhagic fever was discovered in the small town of Marburg in West Germany in the summer of 1967. The first patients all worked at a factory in the town which made vaccines. In the course of their work they had all come into contact with blood or tissue from monkeys from East Africa who were infected with a disease similar to Ebola. Lucy Burns speaks to virologist Werner Slenczka and former laboratory worker Frederike Moos about their experiences of the outbreak.

Photo: A Grivet monkey looks out from an enclosure at Egypt's Giza Zoo in Cairo on August 1, 2017 (Mohamed El-Shahed/AFP via Getty Images)