A research paper has been found showing that a military surgeon at the Imperial Japanese Army Medical School conducted human experiments involving malaria infections on hospitalized Japanese soldiers with mental illnesses during the Sino-Japanese War (1937–1945), Kyodo News reported today (August 17).

According to the relevant paper identified by researcher Matsuno Seiya at the International Peace Research Institute of Meiji Gakuin University, a military surgeon at the Army Medical School in 1940 prepared mosquitoes that had fed on the blood of already infected Japanese soldiers and made them bite 10 Japanese soldiers suffering from schizophrenia as part of research to prevent the spread of malaria within Japan.

Malaria is transmitted when a mosquito that has fed on the blood of a person infected with malaria parasites bites someone else.

Subsequent investigations into whether the disease developed reportedly showed that 5 out of the 10 soldiers exhibited high fevers of over 40 degrees Celsius (104 degrees Fahrenheit), headaches, body aches, and loss of appetite due to malaria infection.

The military surgeon observed them for a certain period before administering medication.

It is presumed that the experiment was conducted under the pretext of preventing the disease from spreading back to Japan upon the return of Japanese soldiers, as malaria infections were widespread among them in China at the time.

In particular, Matsuno noted that soldiers with schizophrenia appeared to have been targeted for human experimentation on the grounds that they could no longer be deployed to combat.

Matsuno criticized, "It is likely that the soldiers who became subjects did not accurately understand the details or risks of the experiment," adding, "This reveals a cold-heartedness that if someone cannot contribute to the state or the war effort—regardless of nationality—it is acceptable to use them as subjects, as well as the mindset of treating humans merely as research materials."