Kiyoshi Shiga

was a Japanese physician and bacteriologist. He had a well-rounded education and career that led to many scientific discoveries. In 1897, Shiga was credited with the discovery and identification of the Shigella dysenteriae microorganism which causes dysentery, and the Shiga toxin which is produced by the bacteria. He conducted research on other diseases such as tuberculosis and trypanosomiasis, and made many advancements in bacteriology and immunology.

Personal life Shiga was born in Sendai, Miyagi Prefecture. His original surname was Satō, but he changed it to his mother's maiden name, Shiga, after being brought up by his maternal family. It was at the university when he was introduced to Kitasato Shibasaburō, one of Robert Koch's successors, who was a world-famous Japanese scientist studying the bacteriology and immunology of deadly disease at the time. The bacterium Shigella was thus named after him, as well as the Shiga toxin, which is produced by the bacterium. After the discovery of Shigella, Shiga worked with Paul Ehrlich in Germany from 1901 to 1905.

Discovery of Shigella dysenteriae

After graduating from the Tokyo Imperial University school of medicine, Kiyoshi Shiga began his career as an assistant to Kitasato Shibasaburō at the Institute for the Study of Infectious Diseases. While studying many infamous diseases at the time, Kitasato and his colleagues, including Shiga, turned their focus to discovering the microorganism that caused the dysentery outbreak in 1897. The discovery of the gram-negative bacillus led to the identification of other species of bacteria with similar characteristic. These species of bacteria are classified under the Shigella genus. Through further studies of the S. dysenteriae bacteria, Shiga was able to discover the Shiga toxin that is produced by the organism. With this new discovery, Shiga attempted to make a vaccine from the toxin. After the Shigella dysenteriae discovery, Kiyoshi Shiga worked with Paul Ehrlich in Europe on discovering chemotherapy methods for a blood diseases called trypanosomiasis which was caused by a protozoan microorganism. Paul Ehrlich is known for his work with dyes and their ability to distinguish and kill certain bacteria and tissues. Ehrlich's previous research, before working with Shiga, lead to the discovery of chemotherapy. It was his transportation of the samples that lead scientist to culture and produce a vaccine and tuberculin to fight the disease.