was a Japanese

physician A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...

and

bacteriologist A bacteriologist is a microbiologist, or similarly trained professional, in bacteriology -- a subdivision of microbiology that studies bacteria, typically pathogenic ones. Bacteriologists are interested in studying and learning about bacteria, ...

. 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 Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, expressed by genes considered to be part of the genome of lambdoid prophages. The toxins are named after Kiyoshi Shiga, who first described the bacterial or ...

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. Shiga was raised during Japan's Industrial age and restoration. The changing times put financial troubles on his family. In 1900, Kiyoshi Shiga married Ichiko Shiga and in the following years had eight children. He faced many family hardships. Shiga lost his wife in 1944 to stomach cancer, his eldest son to turbulent seas during a voyage, and another son to tuberculosis.

Career

Kiyoshi Shiga attended the Medical School of

Tokyo Imperial University , abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project by ...

in 1896, after his high school studies. It was at the University when he was introduced to

Kitasato Shibasaburō Baron 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. Kitasato was nominate ...

, one of Robert Koch's successors, who was a world famous Japanese scientist studying the bacteriology and immunology of deadly disease at the time. Shiga's fascination with Kitasato and his work lead him to pursue a career at the Institute for the Study of Infectious Diseases directed by

. While working for the Institute, Shiga became famous for the discovery of '' Shigella dysenteriae'', the organism that causes

dysentery Dysentery (UK pronunciation: , US: ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications ...

, in 1897, during a severe epidemic in which more than 90,000 cases were reported, with a mortality rate approaching 30%. The bacterium ''Shigella'' was thus named after him, as well as the

, which is produced by the bacterium. After the discovery of ''Shigella'', Shiga worked with

Paul Ehrlich Paul Ehrlich (; 14 March 1854 – 20 August 1915) was a Nobel Prize-winning German physician and scientist who worked in the fields of hematology, immunology, and antimicrobial chemotherapy. Among his foremost achievements were finding a cure ...

in Germany from 1901 to 1905. When he returned to Japan, he resumed the study of infectious diseases with Kitasato. Shiga became a professor at Keio University in 1920. From 1929 to 1931, Shiga was the president of

Keijō Imperial University , colloquially referred to as , was an Imperial University of Japan that existed between 1924 and 1946. This university was established in 1924 in Gyeongseong, known as Keijō during the period of Japanese occupation of Korea, now modern-day S ...

in Keijo (Seoul) and was senior medical advisor to the Japanese Governor-General of Korea. Shiga was a recipient of the

Order of Culture The is a Japanese order, established on February 11, 1937. The order has one class only, and may be awarded to men and women for contributions to Japan's art, literature, science, technology, or anything related to culture in general; recipient ...

in 1944. He was also awarded the Order of the Sacred Treasure, 1st class, on his death in 1957. Along with many of his accomplishments, Shiga had written textbooks on bacteriology and immunology that were widely popular, even after his death in 1957.

Discovery of ''Shigella'' ''dysenteriae''

Dark field microscopy revealing Shigella dysenteriae bacteria

After graduating the Tokyo Imperial University school of medicine, Kiyoshi Shiga began his career as an assistant to

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

outbreak in 1897. In 1898, Shiga was able to isolate and identify the microorganism causing the infectious disease by studying patients who had dysentery and following

Koch's Postulates Koch's postulates ( )"Koch"
''

Using

gram stain In microbiology and bacteriology, Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. The name comes from the Danish b ...

ing methods, Shiga was able to further deduce that the microorganism causing dysentery was a

gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

bacillus. Kiyoshi Shiga initially called the bacteria ''Bacillus'' dysenteriae, but the name was later changed to ''Shigella'' ''dysenteriae'' as a tribute to Kiyoshi Shiga. 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. Species of Shigella are further separated by serogroups that represent different serotypes. Through further studies of the ''S. dysenteriae'' bacteria, Shiga was able to discover the

that is produced by the organism. With this new discovery, Shiga attempted to make a vaccine from the toxin. He tested his first attempt, a heat-killed ''S. dysenteriae'' strain vaccine, on himself which proved to be ineffective and caused severe complications. Kiyoshi Shiga continued his efforts and created a passive immunization vaccine that was based on horse serum. Test trials for the passive immunization vaccine showed no beneficial results or immunity to the infection. These setbacks led Shiga to stop any further trials or production of a Shiga toxin-based vaccine.

Research

Shiga had done research on other topics aside from ''Shigella'' ''dysenteriae'' including

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, i ...

leprosy Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...

, and

beriberi Thiamine deficiency is a medical condition of low levels of thiamine (Vitamin B1). A severe and chronic form is known as beriberi. The two main types in adults are wet beriberi and dry beriberi. Wet beriberi affects the cardiovascular system, ...

throughout his career and grew an interest in chemotherapy and immunology. After the ''Shigella dysenteriae'' discovery, Kiyoshi Shiga worked with

in Europe on discovering chemotherapy methods for a blood diseases called

trypanosomiasis Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus ''Trypanosoma''. In humans this includes African trypanosomiasis and Chagas disease. A number of other diseas ...

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. Shiga and Ehrlich's research into chemotherapy dyes lead them to the discovery of trypan red, a drug that was proven to have an effect on trypanosomiasis. In 1905, after the discovery of trypan red, Shiga returned to Japan with an international reputation and continued his work at Kitasato's laboratory. Kiyoshi Shiga also played a role in the development of the BCG vaccine for

. In 1924, Shiga delivered a strain of tuberculosis called BCG Tokyo 172 strain from Paris, France to Japan. It was his transportation of the samples that lead scientist to culture and produce a vaccine and

tuberculin Tuberculin, also known as purified protein derivative, is a combination of proteins that are used in the diagnosis of tuberculosis. This use is referred to as the tuberculin skin test and is recommended only for those at high risk. Reliable admi ...

to fight the disease. Shiga was a supporter of vaccines, but also an advocate for public health prevention and awareness. He participated in many Chinese writings about the education and prevention of diseases such as tuberculosis.

References

Bibliography

* Csuros, Maria. Microbiological Examination of Water and Wastewater. CRC Press (1999). * Kleinman. Pediatric Gastrointestinal Disease (2008). {{DEFAULTSORT:Shiga, Kiyoshi Japanese bacteriologists Japanese microbiologists People from Sendai 1871 births 1951 deaths People of Meiji-period Japan University of Tokyo alumni Recipients of the Order of Culture