Japanese microbiologist who studied the outbreak of bubonic plague in Asia in the 1890s. Almost simultaneously with Alexandre Yersin, he claimed to have discovered the causative agent of bubonic plague.
However, it was Yersin who was ultimately credited with the discovery of the bacillus causing the disease, because Kitasato could not demonstrate that the microorganism he had isolated was, in fact, the causative agent.
The microorganism isolated by Yersin is today recognised as the actual cause of the bubonic plague, and named for him: Yersinia pestis (originally named Pasteurella pestis, because of Yersin's affiliation with the Pasteur Institute). In Japan, however, there is still a sense that Kitasato was treated unfairly, and should be credited with the discovery.