THE ROLE OF INSECTS AS BIOLOGICAL WEAPONS
The following is based on the notes for a seminar presented by R.K.D. Peterson in 1990 at the University of Nebraska. The information is from several published primary and secondary sources listed at the end of this article.
WHAT IS A BIOLOGICAL WEAPON?
Before discussing the role of insects in biological warfare (BW), we need to define biological warfare and just what a biological warfare agent is. The definition is from the 1972 biological weapons convention. The definition for a BW agent is fairly straightforward:
"Microbial or other biological agents, or toxins whatever their origin or method of production, of types and in quantities that have no justification for prophylactic, protective or other peaceful purposes."
This definition includes all living BW agents, including insects, as well as toxins produced from these agents (e.g., the botulinum toxin).
INSTANCES AND ALLEGATIONS OF BW (PRE 1800)
The recorded allegations and instances of BW before 1800 do not involve insects. However, it is important to discuss some of these records to understand the full spectrum of BW.
Solon, the legislator of the Athenians, contaminated the river Pleisthnes with the plant root of helleborous to give the defenders of Kirrha violent diarrhea, which led to their defeat.
ca. 200 B.C.
Carthaginian general Maharbal purposely retreated from his encampment and left behind a large stock of wine that he treated with mandagora, a toxic root which produces a narcotic effect. The enemy, upon drinking the tainted wine, fell into a deep sleep and the Cartheginians returned to slay their enemy.
Hannibal won a naval victory over king Eumenes of Pergamon by firing earthen vessels full of snakes into king Eumenes ships.
There are many records throughout the ages of armies dumping dead humans and animals into wells, ponds, streams, and rivers to pollute the enemies’ water supplies.
Mongol tartars, sieging the port city of Feodosia (then Kaffa) on the Black Sea, finally broke the three-year siege by catapulting plague-infested cadavers over the walls of the city.
The city fell from plague in 1346 and it was suspected that escaping residents of the city introduces plague into Italy, initiating the pandemic (the Black Death) that decimated the European populace between 1348 and 1350.
The next recorded instance of BW was in the new world. Smallpox was strongly suspected of being used against the Indians in the French and Indian War. Sir Jeffrey Amherst, commander in chief of the British forces in the American colonies had two blankets and a handkerchief from a British smallpox hospital sent to Indian chiefs. A smallpox epidemic soon erupted.
INSTANCES AND ALLEGATIONS OF BW (1800-PRESENT)
The American Civil War
The American Civil War marked the first instance of alleged use of an insect as a weapon of war. The Confederacy accused the Union of deliberately introducing the harlequin bug, Murgentia histrionica, into the South.
Tremendous crop damage resulted in the South because of this pest. This allegation was never proven and it now appears that the harlequin bug moved on its own into the South from Mexico. However, humans may have aided in the movement of this pest.
Disease relationships (microbial and insect vector) were elucidated in the early twentieth century. As soon as the mechanisms were known, military planners began to apply them as possible warfare agents.
World War I
None of the belligerent countries in WWI took official notice of BW. No country involved had a BW research facility and there was no BW on a large scale.
BW clearly was used in sabotage operations in the war to end all wars. In 1915, German agents inoculated horses and cattle that were leaving the U.S. for allied ports with glanders and anthrax. In 1917, the Germans again were accused of spreading glanders to 4,500 donkeys on the French front, and of spreading plague on the Russian front in 1915 and 1916.
As most people know, WWI was known more for the development of chemical weaponry, which was spawned by advances in the dye industry.
Between the Wars
17 June 1925. Geneva Protocol for the prohibition of the use in war of asphyxiating, poisonous or other gases, and of bacteriological methods of warfare. Even though biological weapons were not used on a large scale in wwi, the framers of the Geneva Protocol viewed BW as a serious emerging threat and incorporated a bacterial warfare component into the protocol. Most major countries in the world at that time ratified the treaty.
The United States, however, did not ratify the treaty because of the then current isolationist movement in this country. The U.S. finally ratified this treaty in 1975, 50 years after its inception. The failure of the U.S. to ratify the treaty led the Japanese to not ratify the treaty either and to believe that BW was promising and had a future in warfare.
World War II
The world still is heavily influenced by the events that took place from 1939-1945, and in some respects the war finally ended less than a month ago with German reunification.
World War II also was pivotal when we consider the development and use of BW. I need to look at each belligerent country's involvement because each country's involvement was unique, both axis and allied.
German involvement in BW was not nearly as advanced as Japan or the Allied Nations. It now appears that BW and BW research was not taken seriously by the German military hierarchy. Hitler, especially, viewed the emerging sciences as some sort of Jewish plot. He called the physics of Einstein, Jew physics, and felt similarly about the new biology, and the new psychology.
After the successful Russian counterattacks in Russia in 1943, Hitler agreed to establish an SS BW research station at Posen. As the Russians got closer to the research station, work accelerated at the station, but no real advances were made before the Russians occupied the station in March 1945.
At the Posen BW research station, the Germans performed work on the diseases plague, cholera, typhus, yellow fever, and performed experiments on the feasibility of using insects such as the Colorado potato beetle to attack Allied potato crops. The Germans were accused of dropping cardboard boxes filled with Colorado potato beetles over England from 1941-1943. The containers were never recovered but abnormalities associated with the presence of the beetles prompted Sir Maurice Hankey, head of Britain's BW effort, to write a memo to Winston Churchill with his concerns.
Also, as British invasion fears grew after the successful evacuation from Dunkirk, rumors spread that the Germans had created an omnivorous strain of grasshopper which would soon starve the British into surrender. This was a myth. However, the fact that Nazi doctors used human subjects for experiments on insect-borne diseases is no myth. Concentration camp inmates were intentionally infested with typhus-infected lice by SS doctors at Natzweiler, Dauchau, and Buchenwald. Many of these doctors and scientists were sentenced to death by the Nuremberg Tribunal after the war.
GREAT BRITAIN AND THE COMMONWEALTH
England had a viable BW research program since 1934. After hearing that Germany was initiating a program in 1936, a BW advisory group was established which procured antisera for human and animal diseases, and stocked insecticides and fungicides as a contingency for anti-crop attacks.
In 1939, the BW advisory group assessed BW as less effective than the conventional forms of warfare, but they advised the government to begin a BW research effort.
In 1940, shortly after the fall of France, a BW research unit was established within the chemical warfare research establishment at Porton Down. An experiment conducted in 1941 involved the dissemination of anthrax spores from small aircraft bombs at Gruinard Island off the northwest coast of Scotland. All the other work at Porton Down has been heavily classified and still is unavailable. The only reason the Guinard island episode is known to the general public is because the island is still uninhabitable to this day because of the presence of anthrax spores.
The British effort was combined with the Canadian effort in 1942. Canada had several BW research stations throughout the country. Field testing was performed at a proving ground near Ralston, Alberta. Not much is known about what was studied there. Apparently Canada feared that North American livestock were very susceptible to Old World diseases so several were studied. As a result they studied rinderpest and a few other diseases. Also, botulinal toxins were studied and antidotes were developed.
After the U.S. Entered the war, Canada and Britain shared their BW research experience with the U.S.
The only verified instance of BW during the war was the use by Japan against the Chinese, from 1937-1945.
The Japanese BW program was headed by General Shiro Ishii, an army surgeon with a doctorate in bacteriology. Before Ishii began his BW efforts, he was famous for developing a portable water filtration system, capable of being transported by army regiments.
Ishii strongly believed that the western powers had advanced BW programs and were prepared to use them. Again, failure of the U.S. to sign the 1925 Geneva Protocol influenced his thoughts and actions.
BW research was considered too risky to study in Japan proper. Therefore, the Japanese puppet state of Manchukuo (formerly Manchuria), under complete Japanese control since 1932, was chosen as an ideal location for the studies.
Mukden POW Camp
In 1936, detachment 731 was formed in the town of Harbin. The official name of the detachment was “Epidemic Prevention and Water Supply Unit of the Kwantung Army." In reality, the mission of unit 731 was to forge deadly new biological weapons for the Japanese army to be used against all possible enemies.
In 1938, the success of the research and development efforts at Harbin necessitated the move of unit 731 to Pingfan, a more secure area outside of Harbin. The Pingfan complex included an insectary among its 150 buildings, where 1000 staff members worked around the clock. In total, with out-stations and personnel in the water purification units, 10,000 people were involved.
Like the German scientists, human subjects were used to study these diseases. As early as 1932, people were taken from prison camps (mainly Chinese soldiers, intellectuals, and local workers). The study subjects were called Marutas, which means logs of wood. This is how they were treated. Unspeakable horrors awaited those that entered the Ro block. No subjects that entered ever left alive.
The subjects were tied to posts and were forced to be bitten by plague-infested fleas. The progression of the disease was then charted very scientifically until the subjects died. If the subject did not die, he or she was usually killed, and the body dissected. Many of the human subjects were vivisected at the Ro block. A room existed there where body parts were kept and catalogued.
Of course, human subjects were used on all the diseases studied at Pingfan. Gangrene was studied by exploding gangrene soaked shrapnel bombs in front of tied up Marutas. Also, frostbite was studied by gradually freezing subjects.
It is estimated that 3600 people were sacrificed by the Japanese scientists in the Ro block. This was addition to possibly more than 200 American and British POW's, who were studied at the Mukden POW Camp. More than 1500 Allied soldiers may have been used in BW experimentation. The Japanese were curious to see if Anglo-Saxons and Caucasians in general responded differently to the treatments than the Chinese subjects.
The Pingfan facility was able to produce 300 kilograms of viable plague germs every month, Yersinia pestis. The facility also produced cholera, typhoid, paratyphoid, dysentery, and anthrax.
Ishii believed quite strongly that plague was a promising weapon of war and the insect vector was needed for delivery to the enemy. Therefore, a four-story granary was built which housed rats used as the plague reservoir. At production height in 1945, 4500 flea breeding machines were set up to produce 100 million fleas every few days. It is estimated that 3 million rats may have been used.
Bombs made primarily of clay were developed for dissemination of plague-infested fleas. Also, saboteur initiation of plague via distribution of rats with plague was studied. Plans were designed for the Japanese balloon bomb to carry pathogens to America. The balloon bombs were used to attempt to ignite forest fires in the Pacific Northwest (albeit with unsatisfactory results).
The actual use of bioweapons distinguished Japan from the other belligerents. Several attacks were launched against China from 1939-45. Plague-infested fleas were disseminated directly out of aircraft or via specialized bombs. In 1944, an assault team was assembled to sprinkle plague-infested fleas around the Saipan airfield, which the Americans held. The ship carrying the assault team, however, was sunk by an American submarine and the mission was never completed.
By war's end, Unit 731 was preparing for a major war with Russia. The enormous breeding program was interrupted when Russia invaded Manchuria on August of 1945. The remaining human subjects were slaughtered by the fleeing Japanese guards and Pingfan was abandoned with most of the complex intentionally set on fire to destroy particularly damaging information. A plague epidemic in the Harbin and Pingfan area occurred almost immediately after the abandonment of Pingfan. It is strongly suspected that escaped rats were responsible.
After the U.S. occupation of Japan, Russia began to begin making protests that the U.S. government knowingly was protecting Japanese BW specialists, and failing to bring them to justice. At the same time, the Truman administration sent a team of bacteriologists to investigate the Japanese BW program during the war.
It now appears that General Douglas Macarthur, who was in charge of the occupation of Japan after the war, and his intelligence staff deliberately withheld contacts and information from the Washington scientists. These U.S. scientists found out, after they granted immunity from prosecution to the Japanese scientists in exchange for their bw knowledge, that the Japanese scientists experimented on human subjects, and specifically American POWs. Immunity would not have been granted had the scientists known this. It appears, however, that Macarthur's intelligence staff knew this, but was so desperate for the Japanese BW information, that they deliberately coached the Japanese interviewees. The fear of Russia as the next major adversary was strong in Macarthur's eyes.
The Soviet Union was so frustrated by this episode, that they had their own trial and sentenced many of the scientists they captured in Manchuria to various prison terms, from 1 to 30 years. Many of the top Japanese BW scientists, however, lived comfortably in Japan, and some went on to become respected scientists of international repute.
Ishii continued to consult with American authorities, especially during the height of the Cold War, and died in 1959 of throat cancer.
THE SOVIET UNION
Russian outrage at the Japanese BW research and use may have been hypocritical. There are numerous reports that the Soviets themselves conducted studies involving human experimental subjects in Mongolia before and during the war. In one account, political prisoners and prisoners of war were chained in tents with pens of diseased rats until the subjects were bitten by the fleas. Supposedly, in the summer of 1941, one of the prisoner/experimental subjects escaped and began an epidemic that was controlled only because the Soviets bombed entire Mongol communities. It may never be known as to what extent Russia was involved in BW before, during, or after the war.
THE UNITED STATES
The U.S. army medical corps maintained a passing interest in BW since the 1920's. However, it was not until 1941 that the U.S. BW research program got off the ground, mainly because BW was viewed as a national security threat as the U.S. was drawn closer to the war.
In 1937, Roosevelt declared that the U.S. would never resort to the use of chemical or biological weapons unless they were first used by the enemy. Roosevelt, however, had to agree to increased research in BW as America was being drawn into the war.
The U.S. may have been one of the last major belligerent nations to research BW, but by the war's end the U.S. was probably the most advanced. By war's end, in August 1945, the U.S. BW effort employed 4,000 civilian and military workers, and vied with the Manhattan project for talented scientists and staff.
In all, the U.S. spent $45-50 million for BW installations during the war. The installations included the main research station at Camp Detrick, Maryland, a field-test station on Horn Island in the Mississippi sound, and a huge field-testing facility at the dug way proving grounds in Utah. Also, an ordnance plant was constructed at Terre Haute, Indiana was converted into BW agent production center.
Little is known about the U.S. BW research during the war. Most of the information is still heavily classified and may never be published. A 500 page monograph exists which details the U.S. effort during the war, but it is unavailable for publication because of its classification.
From the flood of journal papers published, it is known that during the war the bacteria of anthrax, glanders, brucellosis, tularemia, meliodosis, and plague were studied.
The fungus of coccidioimycosis was studied, as well as several plant .pathogens, including rice blast, rice brown-spot disease, late blight of potato, and stem rust of cereals. Also, animal pathogents such as rinderpest virus, newcastle disease virus, and fowl plague virus were studied.
The U.S. also worked on aerosol transmission of pathogens, and freeze-drying of BW agents.
Korea and the Cold War
The U.S. BW research and development continued after WWII. As the cold war heated up, so did the BW effort at Fort Detrick.
In 1952, China accused the U.S. of engaging in germ warfare against the people of North Korea. The Chinese began producing large amounts of evidence which suggested that the U.S. was spreading bacteria-laden insects and other objects over the Korean countryside.
Also plague appeared in areas where it had not been documented for over 500 years.
Chinese entomologists accused the U.S. of distributing disease-carrying anthomyid flies, springtails, and stoneflies with P-51 fighters. Also, accusations were leveled stating that America was contaminating areas with plague infested rats and fleas, and anthrax infested flies and spiders. In all, the U.S. was accused of dropping ants, beetles, crickets, fleas, flies, grasshoppers, lice, springtails, and stoneflies. The alleged associated diseases included anthrax, cholera, dysentery, fowl septicemia, paratyphoid, plague, scrub typhus, and typhoid.
The Chinese set up an international scientific commission for investigating the facts about bacterial warfare. The commission, consisting of scientists from all over the world, ruled that the United States probably did engage in limited biological warfare in Korea.
The U.S. maintains that the commission was nothing more than a communist front, however, and denied all the allegations. The U.S. proposed that the United Nations send a formal inquiry committee to China and Korea and investigate, but China and Korea refused.
Most of the allegations were based on eyewitness reports, photographs of strange paper cartons, anomalous appearances of the insects in question, and testimony by POW's.
It is strange why the Chinese would pick insects such as springtails and stoneflies and allege they were deliberately infected with disease and dropped on Korea. Clearly these insects would not be the best choices if the U.S. wanted to initiate BW.
U.S. and Canadian entomologists claimed that the accusations were ridiculous and argued that the anomalous appearances of insects and appearances of new species to an area could be explained through natural phenomena. The U.S. wrote off the whole incident as communist propaganda, but speculation to this day exists as to whether the U.S. may have been experimenting in the field during the Korean war.
Ten years later it was admitted by Dale Jenkins, the chief entomologist at Fort Detrick, that the U.S. at the time of the allegations was able to initiate BW if they saw fit and this BW would have involved insects as vectors of human diseases. Also, during the Korean War U.S. BW specialists were consulting heavily with former Japanese 731 scientists who were granted immunity from war crimes prosecution.
Despite the allegations and negative press from the Korean war episode, BW research by the U.S. and Britain progressed at an accelerated pace through the 50's and 60's. Britain's BW effort tripled after WWII extensive fundamental research was done, including field testing, and promising results were passed on to the U.S. Top BW leaders in Britain and the U.S. grouped bioweapons in with atomic weapons as "weapons of mass destruction." They felt that situations might exist in which BW agents would be preferable to atomic weapons.
In 1951, BW and chemical warfare were incorporated into official strategic planning by the armed forces of the U.S. Brig. General Rothchild, chemical officer of the Far East command, in 1953 wrote that BW could have played a vital role in the Korean War, by distributing anthrax or yellow fever pathogens into the cold air flows that travel from Siberia through the populated areas of China.
Clearly, BW received strong support among the brass in the U.S. and British armed forces. By the end of the 50's the Fort Detrick labs were set up to breed 130 million yellow fever mosquitoes a month, infect them with yellow fever, and deliver them to the enemy via cluster bombs or from the warheads in a Sergeant Missile. Also, the facilities could accommodate the breeding of 50 million fleas per week. By 1960, the labs were experimenting with malaria, dengue, cholera, anthrax, and dysentery, relapsing fever, tularemia.
The 1960's and Vietnam
After the Cuban Missile Crisis, BW research and testing accelerated even further. President John F. Kennedy wished to balance the defense forces of the U.S. and therefore decided that BW and chemical weapons should be stepped up even further.
In 1962, General Stubbs told congress that insect strains were being developed that were more cold hardy and were resistant to insecticides. All other information pertaining to BW involving insects during the 60's to the present have been classified and have not appeared in the congressional testimonies.
In the early 60's, insects as BW vectors fell out of favor with the scientists and planners. This was due in large part to the successful development of dry biological formulations of toxins and microbes.
With dry formulations of BW agents, the practicality and ease of disseminating diseases was greatly increased. It became easy for pneumonic plague, botulinum toxin, q-fever, and other diseases to be spread reliably and efficiently without the need for insects.
Insects, however, were studied which could vector plant diseases. During the Cuban missile crisis, the U.S. considered destroying the sugarcane crop in Cuba with Fiji disease, which is vectored by leafhoppers.
THE BIOLOGICAL WEAPONS CONVENTION
In 1969, President Nixon called for the unilateral destruction of biological weapons. Three years later, the U.S. signed the Biological Weapons Convention Treaty, which banned the development, production, stockpiling, transfer, and acquisition of BW. In 1975, the U.S. also signed the Geneva Protocol of 1925, which also banned the use of these weapons in war. The treaties, however, do not ban research on BW.
BIOLOGICAL WEAPONS TODAY
BW development after 1975 virtually is unknown. Because all major nations signed the BW convention making BW illegal, little information is available as to what is going on today.
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