Baron Kitasato Shibasaburō was a Japanese physician and bacteriologist. He is remembered as the co-discoverer of the infectious agent of bubonic plague in Hong Kong during an outbreak in 1894, almost simultaneously with Alexandre Yersin.

Alexandre Emile Jean Yersin was a Swiss-French physician and bacteriologist. He is remembered as the co-discoverer of the bacillus responsible for the bubonic plague or pest, which was later named in his honour: Yersinia pestis. Another bacteriologist, the Japanese physician Kitasato Shibasaburō, is often credited with independently identifying the bacterium a few days earlier. Yersin also demonstrated for the first time that the same bacillus was present in the rodent as well as in the human disease, thus underlining the possible means of transmission.