Japanese Use of Plague during World War II


I’ve been reading Sheldon Harris’ Factories of Death: Japanese Biological Warfare, 1932-1945, and the American Cover-up. (Rev. ed, 2002), considered the definitive book on biological warfare in the Pacific theater during WWII. My primary interest is in Japanese research and use of plague in their biological warfare program.  Since this blog is, in part, a research tool, this post is a collection of notes taken specifically on the plague, though the book covers a much wider program. If you ever wondered why plague is a category A bioterrorism agent, what follows will go a long way in explaining.

Lt. Gen. Shiro Ishii (1892-1959) of Unit 731, the biological warfare unit of Imperial Japan.

Lt. Gen. Shiro Ishii was the primary organizer, promoter, and director of the Japanese biological warfare (BW) program. He was involved at all levels from pitch-man to the Japanese military and academia to personally supervising research on human subjects. He began his work research on the potential of biological weapons in the late 1920s.

One of Ishii’s first facilities was called the Zhong Ma Castle in Beiyinhe northern Manchuria. Initially, their test subjects were trouble makers among the Chinese population: criminals, communists, and other suspicious persons. Ishii began by focusing on plague, glanders, and anthrax. Subjects were injected with the pathogen and the course of their disease was monitored; all were extensively autopsied. (p. 33-34) There are numerous reports of autopsies being carried out on the unconscious, as in not yet dead.

In 1939 the stressed Japanese military allowed Ishii to send several BW attacks against Soviet forces in the Nomonhan region. Details of the mission refer to the contamination of water supplies with typhoid but plague, cholera, and dysentery affected both Japanese and Soviet troops during the campaign. Harris is unclear whether these were effects of biological weapons operations or naturally occurring outbreaks. (p. 97-98) In 1942 a Soviet defector to Germany claimed that Soviet biological weapons were field tested during combat in Mongolia (/Manchuria) and that there was a major plague epidemic at that time. (p. 98) With both sides attempting biological warfare and with the level of technology at the time, it is unlikely that it will be possible to unravel the outcome of either the Japanese or Soviet efforts.  The Japanese BW program was developed primarily with a future war against the Soviets in mind, as Japan planned to take land north of Manchuria. The intent of the BW program was to give Japan an advantage over the vast population and natural resources of China and the Soviet Union.

Shiro Ishii built an extensive network of facilities in China for the purposes of research and testing. Some details of these units in respect to plague activity follows:

Manchuria, today split between Russia and China. (Public domain image from the CIA’s World Fact Book via Wikipedia Commons.)

At the beginning of the war, the American biological weapons program was the least developed of all the major combatants. The US military was eager to repair this deficit. American offensive and defensive biological warfare research began at Fort Detrick, Maryland, in 1942. The plague was one of many different pathogens worked on during the war. (p. 210) After the Japanese surrender, American officials were much more interested in extracting intelligence from cooperative Japanese researchers, including Shiro Ishii, than in pursuing justice for the Chinese or even American POWs that were victims of their experiments. To ensure cooperation Shiro Ishii was given immunity from prosecution and no one was ever brought to the war crimes trials in Tokyo for biological warfare.  I will leave issues of justice and the cover-up to journalists and political historians.

I do have to take issue with Harris’ assertion that Shiro Ishii was a good microbiologist. He may have been a good pitchman, organizer and military man but not necessarily a good biologist or physician.  First, I can’t accept that anyone racist enough to mentally justify this work was a competent biologist, much less a physician. Designing and carrying out these ‘experiments’ are the sign of an unstable mind. Methodologically,  ‘try absolutely everything you can think of and something might work’ is not good science, not even in wartime. Even if allied programs did similar things, it is still not good science. He thought more like an engineer than a biologist. The innovation that started his career and gained military attention was the development of a water filtration system to prevent cholera for the military. From a strategic point of view, biological weapons were incredibly risky in the 1940s before the discovery of penicillin and other effective antibiotics. The Japanese military actually had to reign them in out of fears of blow-back. Considering what the Japanese military was willing to do during World War II, this says a great deal.