The dubious honor of creating the first modern biological warfare program goes to Germany. During World War I, horses and mules were heavily relied on to transport food, munitions, and other supplies. In 1915, Germany initiated a biological sabotage program that aimed to cripple the Allied logistics network by killing the animals used to transport supplies. Two diseases that strike animals, anthrax and glanders, were cultivated by the Germans. You can learn more about anthrax in Section One of Unit One. Glanders is a disease that mainly strikes horses, but it can also infect donkeys and mules. The agents were used covertly by the Germans to infect animals and feed that were being shipped to France from neutral countries. These sabotage efforts were relatively small in scale, and had no effect on the outcome of the war.
While Germany eventually decided against pursuing a full fledged biological weapons program, other countries were not so hesitant. During WWI, others had witnessed the devastating effect of disease, which contributed heavily to the number of casualties. Due to advances in the biological sciences, by the 1920's and 30's they had the ability to harness this lethal force.
While several countries are known to have had active biological weapons programs prior to and during WWII, only one country, Japan, actually used biological weapons during this time.
During WWII, the Japanese army created four units to research biological weapons. These units were stationed throughout the Pacific theater, in places such as Singapore, Burma, and China. Of these four units, the most notorious was stationed in the northwestern Chinese province of Manchuria. This unit, designated as Unit 731, is known for the particularly brutal experiments it carried out as part of its efforts to develop biological warfare agents.
The unit, which was in operation from 1932 to 1945, was extremely large for its time, with a staff of over 3,000 scientists. Research was conducted on a variety of pathogens, including those that cause dysentery, cholera, and plague. This research often involved injecting pathogens into human test subjects, who were then dissected to allow Japanese scientists to study the effects of the disease. Although exact numbers are not known, it is estimated that between 5,000 and 10,000 people died as a result of Unit 731's experiments.
Along with this horrendous research, the unit also carried out a number of "field tests" that involved the release of weaponized biological agents over civilian populations. It is believed that at least eleven Chinese cities were attacked in this manner, resulting in 200,000 Chinese deaths. During these attacks, agents were placed in water supplies, sprayed from low-flying aircraft, or tossed directly into Chinese homes. In one experiment, designed to assess whether fleas were an effective way to deliver plague, fleas that had fed on plague infected rats were placed into containers, which were then dropped from aircraft. The containers shattered on impact, releasing the fleas.
As testament to the unpredictable nature of biological weapons, one attack conducted by Unit 731 went out of control. The attack took place in 1941, during what known as the Chekiang campaign. The Japanese army had retreated from a region, and Unit 731 moved in and dispersed a variety of biological agents in an attempt to spread infection among the advancing Chinese army. The attack boomeranged, however, after Japanese troops inadvertently moved into the contaminated area. It is estimated that the Japanese army suffered 10,000 casualties as a result.
Unit 731 was under the leadership of General Shiro Ishii. According to those who taught him during the early years of his life, Ishii was extremely intelligent and very ambitious. He had a strong interest in medicine and a desire to serve his country, so he chose to become a doctor in the Japanese army. While serving at the Kyoto Army Medical Hospital, Ishii read a report issued by the Japanese War Ministry on the 1925 Geneva Protocol, which outlaws the use of biological weapons in war. The report helped to convince Ishii of the need for the Japanese army to develop biological weapons. According to his logic, if biological warfare did not have "distinct possibilities", it would not have been banned by the Geneva Protocol.
Ishii began to vigorously advocate for the Japanese army to create a biological weapons research program. He eventually had his way, and a center was built for him at the Japanese Army Medical College in Tokyo. Ishii felt that in order to ensure the effectiveness of the biological weapons he was developing, he needed to test them on humans. The obvious ethical problems that such research caused apparently did not bother him. Medical schools in Japan at the time Ishii was studying to become a doctor did not include a course on medical ethics in their curriculums, and students did not take the Hippocratic oath upon graduating.
In a speech to Unit 731 staff, someone, mostly likely Ishii himself, said:
"Our God-given mission as doctors is to challenge all varieties of disease-causing microorganisms; to block all roads of intrusion into the human body; to annihilate all foreign matter resident in our bodies; and to devise the most expeditious treatment possible. However, the research upon which we are now about to embark is the complete opposite of these principles, and may cause us some anguish as doctors. Nevertheless, I beseech you to pursue this research based on the double medical thrill; one, as a scientist to exert effort to probing for the truth in natural science and research into, and discovery of, the unknown world, and two, as a military person, to successfully build a powerful military weapon against the enemy."
In spite of the horrible atrocities committed by Unit 731, General Ishii was never prosecuted for his crimes. Instead, he managed to strike a deal with the American government at the end of the war. In return for briefing American intelligence officers about Unit 731's research, Ishii earned complete immunity for himself and his senior officers. Along with the briefings, which took place from 1947 to 1948, Ishii also turned over 1,000s of tissue pathology slides that documented the extent of Japan's biological weapons research. There are several probable reasons why the US agreed to the immunity deal. First, it did not want Ishii's data to fall into the hands of the Soviets. Second, it thought that its own biological weapons research program could use the data. As it turned out, the US program focused mainly on delivering biological weapons in aerosol form, and since the Japanese had used different vectors, the data supplied by Ishii was of relatively little use to American efforts.