Contributiond. Reported discovery of the causative agent of cholera (now Vibrio cholerae) and its growth in pure culture.
NotesKoch's discovery of the cholera agent, a comma-shaped bacterium, is sometimes dated 1883. He did observe it in August-September 1883 while investigating an outbreak of cholera in Egypt. However, he and his team found the organism only in the intestines of cholera victims. They were unable to find it in blood or other tissues and, most important, they were unable to separate it from other intestinal bacteria before the outbreak subsided. They found the organism in cholera victims in India in December 1883 and January 1884 and succeeded in isolating it in pure culture. Koch described their findings in a report written in February 1884. Koch's isolation of the comma-shaped bacterium in pure culture did not prove that it was the cause of cholera, and the deficiency was accentuated by his failure to infect animals experimentally. His claim that the microbe caused cholera met with skepticism and even intemperate rejection, but the circumstantial evidence was strong enough to overcome opposition. His discovery had more impact in defeating miasmatism than his work on anthrax or TB (because the latter was not "dramatically epidemic," see McNeill p. 267). For highly relevant earlier reports see 1854 Hassall and 1854 Pacini. For a valuable historical summation and convenient list of Koch's reports, see N. Howard-Jones, Brit. Med. J. 288:379-381, 1984.
Pathogen ClassBacteria

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