Frosch, Paul

Paul Frosch (1860–1928) was a German bacteriologist and a pioneer of animal virology. He worked at the Institute for Infectious Diseases in Berlin as a close co-worker of Robert Koch, the leading figure of medical bacteriology, and became later appointed professor at the veterinary school in Berlin. On the basis of a study on typhoid, Frosch introduced the term ‘infection carrier’ for infected persons without manifest symptoms, and emphasised the role they played in spreading the epidemic. The concept subsequently became the cornerstone of epidemic control for a variety of infectious diseases in Germany. In 1898, Frosch pioneered virus research when he described the aetiological agent of the foot-and-mouth disease together with Friedrich Loeffler, characterising it as an ultravisible, filterable substance.