Japanese bacteriologist, chiefly noted for his discovery (1897) of the dysentery bacillus Shigella, which is named after him.

Shiga graduated from the University of Tokyo in 1896. Two years earlier he had begun work with Kitasato Shibasaburo, who had discovered the tetanus bacillus. In 1899 Shiga was appointed laboratory director at the Institute for Infectious Diseases in Tokyo. Shortly thereafter he went to Europe and worked with Paul Ehrlich (Ehrlich, Paul), a German bacteriologist, on developing chemotherapy for trypanosomiasis, a blood disease caused by a protozoan micro-organism. In 1900 Shiga developed a dysentery antiserum. Returning to Tokyo in 1903, he resumed work with Kitasato at his institute. In 1920 Shiga was appointed professor of bacteriology at the University of Seoul and in 1929 was named that university's president. Two years later he returned to Tokyo and in 1936 was appointed an official of the imperial household. His research also included work on leprosy, beriberi, and tuberculosis.