During World War II , the Japanese Army developed weaponised plague , based on the breeding and release of large numbers of fleas . During the Japanese occupation of Manchuria , Unit 731 deliberately infected Chinese , Korean and Manchurian civilians and prisoners of war with the plague bacterium . These subjects , termed " maruta " or " logs " , were then studied by dissection , others by vivisection while still conscious . Members of the unit such as Shiro Ishii were exonerated from the Tokyo tribunal by Douglas MacArthur but 12 of them were prosecuted in the Khabarovsk War Crime Trials in 1949 during which some admitted having spread bubonic plague within a 36-km radius around the city of Changde
Unit 731
Unit 731
Plague (disease)