By The Straits Times | Created at 2026-08-18 07:52:18 | Updated at 2026-08-18 08:05:24
25 minutes ago
TOKYO - The Imperial Japanese Army conducted experiments on its own soldiers during the Second Sino-Japanese War, exposing troops hospitalised for mental illnesses and deemed unfit for combat to malaria-carrying mosquitoes, a researcher at Meiji Gakuin University said on Aug 17.
Military doctors studying the transmission of malaria exposed 10 soldiers hospitalised in Japan, who had conditions including schizophrenia, to mosquitoes that had fed on the blood of infected troops.
The doctors from an army medical school conducted the study to prevent the spread of the disease within Japan, according to Seiya Matsuno of the university’s International Peace Research Institute, who confirmed the existence of a paper detailing the research.
“It is possible the soldiers who were used as test subjects did not fully understand the nature of the experiments or the risks involved,” Matsuno said.
The paper contained descriptions indicating that the experiments were supervised by Shiro Ishii, known for having led the army’s Unit 731 that conducted human experiments on prisoners of war in northeastern China for biological and chemical warfare research.
Highlighting the fact that the army conducted experiments on its own soldiers too, Matsuno said: “This reveals a callous attitude that viewed those who could not contribute to the nation or the war effort, regardless of nationality, as acceptable test subjects and a mindset that viewed human beings as merely research material.”
Malaria can spread when a person is bitten by a mosquito carrying the malaria parasite. Symptoms, including high fever and body aches, can become severe and result in death.
According to the paper published in the journal of the army medical corps, the experiments were conducted in 1940 at an army hospital in Chiba Prefecture neighbouring Tokyo, which housed soldiers with mental illnesses.
While there were other cases at the hospital of army doctors conducting experiments on soldiers hospitalised with mental illnesses, this was the earliest confirmed research to date, Matsuno said.
Of the 10 test subjects, five developed symptoms after an incubation period and experienced fevers of over 40 deg C, body aches and loss of appetite, according to the paper.
After a period of observation, medication was administered.
Malaria infections were widespread at the time among Japanese military personnel on the Chinese mainland. KYODO NEWS
