Kitasato Shibasaburō
Japanese bacteriologist who co-discovered the plague bacillus.
Baron Kitasato Shibasaburō was a Japanese physician and bacteriologist whose career spanned groundbreaking laboratory research, public health work, and institutional leadership. Born in what is now Kumamoto Prefecture on Kyūshū, he was the son of a village head and a mother from a samurai family, who emphasized discipline and education. After studying at Kumamoto Medical School and a predecessor of Tokyo Imperial University, he traveled to Berlin to train under Robert Koch from 1885 to 1891. There, in 1889, he became the first scientist to grow the tetanus bacillus in pure culture. The following year, he collaborated with Emil von Behring to develop a serum therapy for tetanus using that pure culture, and they demonstrated that injecting graded doses of blood serum from an infected animal could create passive immunity in another animal. This work on tetanus, together with von Behring’s parallel research on diphtheria, established the field of serotherapy. Kitasato also worked on antitoxins for diphtheria and anthrax. Despite being nominated for the first Nobel Prize in Physiology or Medicine in 1901, only von Behring received the award for their joint discovery of diphtheria antitoxin serum. Returning to Japan in 1891, Kitasato founded the Institute for Study of Infectious Diseases with the help of Fukuzawa Yukichi. He showed that dead bacterial cultures could be used for vaccination and studied tuberculosis transmission. In 1894, at the Japanese government’s request, he traveled to Hong Kong during a bubonic plague outbreak and identified a bacterium he believed caused the disease. Alexandre Yersin independently found the same organism days later. Although Kitasato’s early reports were vague and later ones inaccurate—likely because his samples became contaminated with pneumococci—microbiologists later concluded he did isolate and characterize the plague bacillus. Four years later, with his student Shiga Kiyoshi, he isolated the dysentery organism. He later researched epidemic plagues in Northeast Asia and studied pneumonic plague prevention in Manchuria. When his institute was absorbed by Tokyo Imperial University in 1914, he resigned and founded the Kitasato Institute, which he led for life, and helped establish a medical facility that became a major learning center. In 1921, he co-founded a company to manufacture reliable clinical thermometers, later rena
- nationality
- Japanese
- known_for
- Co-discovery of bubonic plague bacillus
Verified Timeline
Lore & Background
The Japanese government sent Kitasato Shibasaburō to investigate the plague in Hong Kong. On 5 June, Kitasato departed Yokohama on SS City of Rio de Janeiro with a team of 5, arriving in Hong Kong on 12 June. On 14 June, Kitasato discovered that the bacillus, now known as Yersinia pestis, was the direct cause of the plague. However, he was doubtful of its significance as the autopsy was done 11 hours after death. His finding was reported by James Alfred Lowson to The Lancet, and his report was published a week later, on 25 August. Kitasato's description lacked precision, and the report was riddled with doubts and confusion. Kitasato insisted that his organism was Gram-positive, while Yersin correctly described his as Gram-negative. Kitasato described his blood organism as diplococcal and his bubo organism as bacillary, causing confusion and suggesting to some that his cultures were contaminated by the pneumococcus. In the ensuing months and years, Kitasato asserted that his bacillus was different from that of Yersin.
Reader's Guide
Kitasato Shibasaburō’s career was defined by foundational contributions to bacteriology and serotherapy. While studying under Robert Koch in Berlin, he achieved the first pure culture of the tetanus bacillus in 1889. Collaborating with Emil von Behring, he helped develop a serum therapy for tetanus by demonstrating that injecting graded doses of blood serum from an infected animal could induce passive immunity in a healthy animal. This work, alongside von Behring’s on diphtheria, established the field of serotherapy. Kitasato also showed that dead bacterial cultures could be used for vaccination and studied tuberculosis transmission. In 1894, during a bubonic plague outbreak in Hong Kong, he identified the causative bacterium almost simultaneously with Alexandre Yersin. Although later confusion arose over his organism’s Gram stain and morphology—likely due to pneumococcus contamination—microbiologists now agree he isolated and characterized the plague bacillus. Four years later, with his student Shiga Kiyoshi, he isolated the dysentery pathogen. After returning to Japan, he founded the Institute for Study of Infectious Diseases with Fukuzawa Yukichi, and later the Kitasato Institute after resigning when his institute was absorbed by Tokyo Imperial University. He also organized a major medical facility, co-founded the company that became Terumo Corporation, and served as first dean of medicine at Keio University, first president of the Japan Medical Association, and a member of the House of Peers. Ennobled as a baron in 1924, he continued researching tuberculosis and public health until his death from intracranial hemorrhage in 1931. His portrait appears on Japan’s 1,000 yen banknote issued in 2024.
Did You Know?
- Kitasato Shibasaburō departed Yokohama on 5 June 1894 on the SS City of Rio de Janeiro with a team of 5 to investigate the plague in Hong Kong.
- He discovered the plague bacillus on 14 June 1894, three days before Alexandre Yersin arrived in Hong Kong.
- Kitasato's initial report was published in The Lancet on 25 August 1894, just a week after his finding.
- Kitasato insisted his organism was Gram-positive, while Yersin correctly described his as Gram-negative.
- Kitasato described his blood organism as diplococcal and his bubo organism as bacillary, causing confusion and suggesting possible contamination by pneumococcus.
Frequently Asked Questions
Who is Kitasato Shibasaburō?
Kitasato Shibasaburō (1853–1931) was a Japanese physician and bacteriologist born in Okuni village, Higo Province. He is best remembered for his groundbreaking work in identifying infectious disease agents and advancing serotherapy in the late 19th century.
What is Kitasato Shibasaburō most famous for?
He is celebrated as the co-discoverer of the bubonic plague bacillus during the 1894 Hong Kong outbreak, a finding made almost simultaneously with Alexandre Yersin. His collaborative work with Emil von Behring on diphtheria antitoxin serum and tetanus therapy also laid the groundwork for modern serotherapy.
How did Kitasato Shibasaburō discover the plague bacillus?
During the 1894 epidemic in Hong Kong, Kitasato isolated the infectious agent responsible for bubonic plague. His identification of the bacterium was made nearly at the same time as Yersin's, which is why both are credited as co-discoverers.
Did Kitasato Shibasaburō win a Nobel Prize?
He did not win, but he was nominated for the very first Nobel Prize in Physiology or Medicine in 1901. The prize ultimately went to others that year, though his contributions to serotherapy and plague research were widely recognized by the scientific community.
What lasting legacy did Kitasato Shibasaburō leave in medicine?
Beyond his plague and antitoxin research, he founded the Kitasato Institute, which became a major center for medical and biological research in Japan. His work on tetanus and diphtheria therapies helped establish the principles of using antitoxin serums to treat infectious diseases.
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