thesis statement about biological warfare

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Unit 731 and the Japanese Imperial Army’s Biological Warfare Program

November 24, 2005

Volume 3 | Issue 11

Article ID 2194

https://apjjf.org/wp-content/uploads/2023/11/article-1720.pdf

By Tsuneishi Keiichi

Translated by John Junkerman

[ Japan’s Unit 731 remains central to the fiercely contested China-Japan controversy over war crimes and war memory, and to the international debate on science and ethics. With a staff of more than 10,000, including many of Japan’s top medical scientists, 731 and its affiliated units conducted human experiments, including vivisection, on Chinese and other victims in Manchukuo and throughout China between 1933 and 1945. The experiments tested, among other things, the lethality of biological weapons and sought to determine the ability of the human body to survive in the face of various pathogens and in conditions such as extreme cold.

Tsuneishi Keiichi is Japan’s leading specialist on biowarfare. His voluminous studies conducted over thirty years in Japan, China, the United States and Europe, have provided core material for all writing hitherto on the Ishii Network. In the following careful resumé essay, he concentrates on organization and function, omitting much of the horrific detail covered elsewhere. Drawing on Japanese military records, this study documents the deaths of 850 victims in the years up to 1943, the largest number infected with plague, cholera, and epidemic hemorrhagic fever. It also makes use of American records and interviews.

Unit 731 not only conducted tests but also led the way in waging biological warfare on numerous occasions throughout the war, the best documented being attacks on Ningbo and throughout Zhejiang province. As in the case of the Nanjing Massacre and the “comfort women,” casualty figures remain contested. The figure of 3,000 persons exterminated at Pingfan, the major experiment site of the Ishii Network, is widely accepted among specialists for the period ending in 1945. The post-surrender destruction by the Japanese authorities both of the research sites and the military documents, has made precise casualty estimates difficult.

As Tsuneishi documents, attacks in Zhejiang resulted in more than 10,000 Japanese military casualties including the death of 1,700 Japanese soldiers, revealing the difficulty of waging effective biowarfare. No estimate is provided here of Chinese deaths. a reminder of contemporary practice in providing only American body counts in Iraq, but also of the difficulty of establishing Chinese casualties.

Japan’s grim experiment with biowarfare pales in comparison with the estimated 10-30 million Chinese who died as a result of war and associated conditions of famine in the years 1931-45. But the findings of Ishii and his colleagues were important enough for American authorities to grant immunity from prosecution in exchange for evidence of the research findings of Unit 731. The 731 scientists, who were evacuated to Japan prior to the defeat, continued their careers as eminent figures in the postwar medical and scientific establishment. ms ]

The Ishii Network

Unit 731 was the common name of a secret unit of Japan’s Manchuria-based Kwantung Army whose official name was the Epidemic Prevention and Water Supply Department. [1] The leader of the unit was Ishii Shiro, who held the rank of lieutenant general at the end of World War II. The unit epitomized the extensive organization for the development of biological weapons within the imperial army, which was referred to, beginning in the late 1930s, as the Ishii Network.

The network itself was based at the Epidemic Prevention Research Laboratory, established in 1932 at the Japanese Army Military Medical School in Tokyo. Unit 731 was the first of several secret, detached units created as extensions of the research lab; the units served as field laboratories and test sites for developing biological weapons, culminating in the experimental use of biological weapons on Chinese cities. The trial use of these weapons on urban populations was a direct violation of the 1925 Geneva Protocol, which outlawed the use of biological and chemical weapons in war. It was also understood by those involved that the use of human subjects in laboratory and test site experiments was inhumane. This was why it was deemed necessary to establish Unit 731 and the other secret units.

The Epidemic Prevention Research Laboratory was created under the initiative of Ishii Shiro after he returned from two years of field study of American and European research facilities. It was set up, with the approval of top-level army authorities, as a facility to develop biological weapons. It is said that Ishii first became convinced of the need to develop biological weapons with the signing of the Geneva Protocol in 1925.

The biological weapons Ishii sought to develop had humans as their target, and Unit 731 was established with this goal in mind. In order to produce biological weapons as quickly as possible, Ishii considered it essential to have a human experimentation site at the disposal of his research laboratory. Japan had occupied northeastern China and in 1932 the puppet state of Manchukuo was established. Within this “safe zone,” Ishii set up what was called the Togo Unit, based in the village of Beiyinhe, about 100 kilometers south of Harbin. Human experimentation began there in the fall of 1933. The Togo Unit was a secret unit under the vice chief of staff of the Kwantung Army. It was set up to determine whether it was possible to conduct human experiments in northeastern China, and if it was possible, whether the experiments would produce useful results. The launching of this feasibility study reflects the deliberate nature of Ishii as the organizer of the research, and you could say it was marked with his character. All of those involved in this research and development were military doctors, but they all used false names. At this stage, the scale of the project involved about ten doctors, along with a staff of about one hundred.

The Inauguration of Unit 731

Unit 731 was officially established in 1936. Its establishment is reflected in a memo dated April 23, 1936, entitled “Opinion Regarding the Reinforcement of Military Forces in Manchuria,” from the chief of staff of the Kwantung Army to the vice minister of the Ministry of War (contained in the Ministry of War Journal for the army in Manchuria, Rikuman Mitsu-dainikki). Under the heading “Establishment and Expansion of the Kwantung Army Epidemic Prevention Department,” the memo states that the department will be “newly established” in 1936 and “one part of the department will be expanded in fiscal 1938.” This is the oldest official document concerning Unit 731 that has been found to date.

In addition to inaugurating Unit 731, this memo also laid the foundation for establishing two other units. It called for the establishment of an additional biological weapons development unit, independent of Ishii’s unit, which was called the Kwantung Army Military Horse Epidemic Prevention Workshop (later referred to as Manchuria Unit 100), and for preparations to set up a chemical weapons development unit called the Kwantung Army Technical Testing Department (later referred to as Manchuria Unit 516).

Several months later, the memo’s recommendations were approved by Emperor Hirohito, the two units were established, and preparations began for creating the Testing Department. The Ministry of War Journal for May 21, 1936 recorded this development under the heading. “Imperial Hearing on Military Force Improvement Consequent upon Budget Approval.” The journal noted: “Units concerned with epidemic prevention: One unit each is established for epidemic prevention among humans and horses.”

Having been officially established, Unit 731 moved its facilities from Beiyinhe to a newly established laboratory at a hospital in Harbin. This laboratory served as a front-line headquarters while the unit’s permanent facilities were being built in Pingfan, outside of the city of Harbin. These facilities were completed and capable of conducting research in the fall of 1939, after the hostilities at Nomonhan (on the border between Manchuria and Mongolia) had ended.

With the construction of the Pingfan facilities, the primary research staff changed in composition from the military doctors of the Togo Unit to private-sector medical researchers affiliated with universities and other institutions. The first group to be posted to the unit was a team of eight assistant professors and instructors from Kyoto Imperial University in the spring of 1938. The group consisted of two bacteriologists, three pathologists, two physiologists, and one researcher specializing in experiments using animals. Within a year, a second group had arrived at the facility, and the research staff had expanded considerably. The prominence of researchers in pathology and physiology in the development of biological weapons reflected the need for specialized judgment in assessing the results of human experimentation.

With the expansion of the war front throughout China after 1937, sister units affiliated with Unit 731 were established in major Chinese cities. These units were also called Epidemic Prevention and Water Supply Departments. (Unit 1855 was established in Beijing on February 9, 1938; Unit 1644 in Nanjing on April 18, 1939; and Unit 8604 in Guangzhou on April 8, 1939). Later, after Japan occupied Singapore a similar unit (Unit 9420) was established there on March 26, 1942. These affiliates comprised the scope of the Ishii network through the end of the war. As of the end of 1939 (that is, before the establishment of the Singapore unit), the network had a total staff of 10,045, of which 4,898 were assigned to the core units in Tokyo and Pingfan.

Human Experimentation

Human experimentation took place at all of the units of the Ishii network, but it was conducted systematically by Unit 731 and Unit 1644. Of these two, there are extant reports from a US Army survey of human experimentation by Unit 731, so the general outline of its program is known.

The following table was compiled from two sources: a report to US occupation authorities dated December 12, 1947 by Edwin Hill and Joseph Victor, concerning human experimentation by Unit 731 and related facilities; and a list of specimens brought back to Japan by a Unit 731 pathologist in July 1943. Aside from Ishii and another unit leader, Kitano Masaji, the names of individual researchers do not appear; they are identified as military personnel (M, primarily military doctors), (C) civilian technicians conducting research within the military, and (PT) part-time researchers working outside of the military.

The number of specimens reflects the number of subjects who died as a result of human experimentation as of July 1943. Consequently, the total number of victims of human experimentation at the time of Japan’s surrender two years later would be higher than these figures. The figures also do not include victims of germ bomb tests at the Anda field test site or from other experiments.

Subject Researcher Total Specimens Medically Usable Specimens anthrax M 36 31 botulinus Ishii 2 0 brucellosis Ishii, M, C, M 3 1 CO poisoning 1 0 cholera C, C 135 50 dysentery M, M, PT, PT, M 21 12 glanders Ishii, C 22 20 meningitis Ishii, C 5 1 mustard gas 16 16 plague Ishii, C, M, C 180 42 plague (from the Shinkyo [Changchun] epidemic) 66 64 poison 2 0 salmonella M, C 14 11 Songo (epidemic hemorrhagic fever) C, Kitano, C 101 52 smallpox Ishii, C 4 2 streptococcus 3 1 suicide 30 11 tetanus Ishii, PT, C 32 14 tick encephalitis C, Kitano 2 1 tsutsugamushi (scrub typhus) C 2 0 tuberculosis C, Ishii 82 41 typhoid C, C 63 22 typhus C, M, C, Kitano, C 26 9 vaccine 2 2 Total 850 403

Technicians who were civilian employees of the army were treated as officers. The status of civilian employees ranged from infantry-class to general-class, but technicians were treated as lieutenants and above. Ranking below the technicians were operators, clerks, and staff. For the most part, the Ishii network took on university researchers as technicians. The part-time researchers were part-time employees of the Military Medical School Epidemic Prevention Research Laboratory; they were professors at Tokyo and Kyoto imperial universities who were contracted to perform research in their own laboratories. In short, a large number of civilian researchers were mobilized.

Biological Warfare Trials

For the most part, the use of the biological weapons developed by the Ishii network amounted to field trials.

The first of these trials took place during the Nomonhan Incident in 1939. In August, toward the end of the hostilities, pathogens that cause gastrointestinal disease were placed in the Holsten River, a tributary of the Halha River that the Soviet Army used as its source of water. It is not clear how many Soviet soldiers suffered from this attack, but it is thought that casualties were not widespread. This was because the typhoid bacillus and the other pathogens that were used lose their infectivity when placed in water. This fact was known to Ishii’s group. It is thought that they nonetheless carried out the attack because they wanted to conduct a field test of biological weapons in combat. While there were likely few Soviet casualties, at least one Japanese soldier became infected when he spilled liquid from a drum filled with contaminated water while dumping it into the river. He died of typhoid fever at an army hospital in Hailar.

During the following year, 1940, larger scale field trials were conducted in central China, using biological weapons dropped from airplanes. The pathogens were cultivated by Unit 731 and shipped to Unit 1644 in Nanjing, which served as the forward base for the attacks, which continued until 1942. During the first two years, these attacks were carried out in cities along the Chang River. Of these, the large-scale attack on the city of Ningbo on October 27, 1940 is well documented and has also been thoroughly investigated by the Chinese.

The attack took place at 7 a.m. from heavy bombers flying a low-altitude run at 200 meters. The bombers dropped fleas, grain, and strips of cotton on the streets in the center of the city. The fleas were infected with the plague. They had ingested blood from plague-infected rats and were called “plague fleas.” The plague bacteria were not dissipated directly, as it was considered more effective to infect the carrier fleas and release them, in order to target a specific area with a focused attack. It was also expected that the bacteria would live longer in the bodies of the fleas. The fleas were dropped with grain and cotton to ensure that they reached the target area, and it was also thought that the cotton would absorb some of the shock of impact on the ground.

The first death was recorded on the fourth day, October 30, and casualties increased rapidly in the days that followed. By November 2, it was clear that the disease was an epidemic, and the area was sealed off as disease-contaminated. The next day, it was determined that the disease was the plague. By then 37 deaths had been reported. The quarantine imposed on the area slowed the spread of the epidemic.

The plague epidemic ended on December 2 with the death of the last two victims. Deaths totaled 106 people. These figures were reported in a survey, conducted by two Ningbo researchers and published in March 1994 by Dongnan University Press. This historical account of the epidemic tracked down all of the victims and listed them by name, and it is thus a very valuable document.

This attack, killing more than one hundred people, was the most lethal in this series of attacks on Chinese cities. However, when one considers that the attack was carried out by heavy bombers on a risky low-altitude run, these results have to be considered a military failure.

There were two primary reasons for this failure. First, the bacteria used was so infectious that it immediately set off alarms among its victims. Second, the effort suffered from exaggerated expectations of the ability to artificially spark an epidemic. In February 1941 Ishii reported to his superior officer, Lt. Gen. Kajitsuka Ryuji, chief of the medical department of the Kwantung Army: “It is not as easy as some people think, and as I once thought, to deliberately spread infectious disease. While infectious disease spreads readily in natural circumstances, numerous obstacles are encountered when artificially spreading infection, and sometimes great pains must be taken to overcome these.” [2] It was expected that pathogens dropped in a densely populated area like Ningbo would quickly spread person to person, but these expectations were betrayed.

Great Failures

In November 1940, the month after the attack on Ningbo, the Chinese began to take countermeasures in response to biological warfare attacks on urban populations. On November 28, the central Chinese city of Jinhua suffered an attack. The result was a failure. According to a Chinese Ministry of Health document, “At the time that the plague epidemics were continuing in Ningbo and its vicinity, three Japanese airplanes flew over Jinhua and dropped a large number of small granules the size of small shrimp eggs. These strange objects were gathered and examined at a local hospital. . . . They showed the physical characteristics of the bacteria that cause the plague. In any case, the plague did not break out in Jinhua and as far as this town was concerned the Japanese experiment in germ warfare ended in failure.”

No effort was made to collect the material dropped from the airplanes on Ningbo, but one month later the objects dropped on Junhua were gathered and analyzed. There had been rapid progress in securing evidence in response to the attacks. It is also likely that townspeople were warned to stay inside their houses. As a result, the Japanese experiment was deemed a failure.

Biological weapons are not only useful as potent means of war; their use can also be accompanied by an important element of strategic disinformation, if it is claimed that the enemy itself used them, or if it is implied that they were used in retaliation. In this sense, when biological weapons are used, one tactic is to cause confusion as to whether they were used or not, but if the enemy deems the trial uses a failure, the tactic itself fails decisively.

Nonetheless, the trial use of biological weapons on central Chinese cities continued in the fall of 1941. One of the targets was the city of Changde, about 1000 kilometers east of Shanghai in the Chinese interior. The Chinese applied the lessons they learned the previous year and were able to keep casualties in the single digits. Thus the results of the trials through the end of 1941 indicated that dropping plague fleas from airplanes as a means of attacking urban areas was quite ineffective.

Beginning in 1942, Japan began dropping pathogens from airplanes into battlefield zones, on a scale that amounted to a combat operation. In April, Japan launched the Zhejiang campaign. In this campaign, Ishii and company carried out massive biological weapons attacks. Cholera bacteria was the main pathogen employed, and the attacks resulted in more than 10,000 casualties. It has also been reported that some victims contracted dysentery and the plague. More than 1700 soldiers died, mostly from cholera. This would have been considered a great success for the Ishii group, but for the fact that all of the victims were Japanese soldiers.

A Japanese medic captured by American forces at the end of 1944 described the casualties among the Japanese army during his interrogation: “When Japanese troops overran an area in which a [biological weapons] attack had been made during the Chekiang [Zhejiang] campaign in 1942, casualties upward from 10,000 resulted within a very brief period of time. Diseases were particularly cholera, but also dysentery and pest [bubonic plague]. Victims were usually rushed to hospitals in rear. … Statistics which POW saw at Water Supply and Purification Dept Hq at Nanking showed more than 1,700 dead, chiefly from cholera; POW believes that actual deaths were considerably higher, ‘it being a common practice to pare down unpleasant figures.’” [3]

A New Type of Bomb

After the 1942 failure, the Japanese army general staff lost all confidence in the efficacy of biological weapons. The pressure was on to find a new approach that would ensure the safety of friendly troops and deliver a more reliable, more devastating blow to the enemy.

The new approach developed was to pack the pathogens in bombs or shells, which would be dropped from airplanes or delivered by artillery. This would satisfy both of the requirements, to deliver massive carnage while maintaining the safety of the attacking troops. At the same time, the only way to prevent disasters like that of the Zhejiang campaign was to improve communication among the troops.

Two hurdles confronted the effort to load bombs with pathogens. The first was the need to keep the pathogens alive for long periods of time. The second was the need to develop a bomb made of materials that would break apart upon impact using little or no explosives; this would prevent the pathogen from being destroyed by heat. Alternatively, if a bombshell could not be made of fragile material, a pathogen that could withstand the heat of an explosion would have to be selected. When a bomb or a shell lands, people do not immediately gather at the point of impact, so it was necessary to convey the pathogen from that spot to wherever people were. Again a live host like a plague flea that would physically carry the pathogen and infect people was considered the best solution to this problem.

A bacteria bomb using the plague bacteria was developed to satisfy most of these requirements. The bomb used plague fleas packed in a shell casing of unglazed pottery made from diatomaceous earth (a soft, sedimentary rock containing the shells of microscopic algae). This same material was used in a water filter that Ishii had developed and patented. As this bomb would break apart using minimal explosive, it was expected that the plague fleas inside would survive the heat and scatter in all directions, to bite people and spread the disease. This bomb, called the Ishii bacterial bomb, was perfected by the end of 1944. In the beginning of 1945, the collection of rats went into high gear, and Unit 731 went to work cultivating fleas to be infected with the plague.

Japan’s Defeat

The main force of Unit 731 left the unit headquarters by train soon after the Japanese surrender and returned to Japan between the end of August and early September 1945. Some members of the unit and officers of the Kwantung Army were captured by the Soviet military. Twelve of these POWs were tried by the Soviet Union at a war crimes trial in Khabarovsk in December 1949. In addition to members of Unit 731, officers of the Kwantung Army and the army’s chief medical officer were also charged as responsible parties. All of those charged were given prison sentences ranging from two to twenty-five years, but aside from one man who committed suicide just before returning to Japan, all had been repatriated by 1956. The record of the Khabarovsk trial was published in 1950 as Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons (Foreign Languages Publishing House, Moscow).

On the other hand, not one of the members of Unit 731 who returned to Japan was tried as a war criminal. Instead, the American military began investigating the unit in September 1945, and unit officers were asked to provide information about their wartime research, not as evidence of war crimes, but for the purpose of scientific data gathering. In other words, they were granted immunity from prosecution in exchange for supplying their research data. The American investigation continued through the end of 1947 and resulted in four separate reports. The investigation took place in two phases.

The first phase resulted in the Sanders Report (dated November 1, 1945) and the Thompson Report (dated May 31, 1946). These two reports contained information on the unit’s bacteria bombs, but did not address the subject of human experimentation or the trial use of biological weapons. Kitano Masaji, who was in Shanghai at the time of Japan’s surrender, was interrogated in January 1946, but he was instructed by Lt. Gen. Arisue Seizo, the Japanese chief of intelligence, that he should not talk about “human experimentation and biological weapons trials,” Kitano later told this writer. In other words, until that time, these two subjects had been effectively concealed.

4. Body disposal at Unit 731

However, at the end of 1946, American authorities received notice from the Soviets that they intended to try cases involving human experimentation and biological warfare. Ishii and others were interrogated again, and they confirmed the general content of the Soviet claims. The American investigation began anew, headed by new investigators. Two additional reports were produced: the Fell Report (dated June 20, 1947) and the Hill and Victor Report (dated December 12, 1947). These documents described the human experiments conducted by Unit 731 and its related units, based primarily on the interrogation of researchers involved in the experiments.

The Hill and Victor Report concludes with the following evaluation: “Evidence gathered in this investigation has greatly supplemented and amplified previous aspects of this field. It represents data which have been obtained by Japanese scientists at the expenditure of many millions of dollars and years of work. Information had accrued with respect to human susceptibility to those diseases as indicated by specific infectious doses of bacteria. Such information could not be obtained in our own laboratories because of scruples attached to human experimentation.”

The above account makes clear the nature of the crimes committed by the Ishii Unit. At the same, it is necessary to question the responsibility of the American forces who provided immunity from prosecution in exchange for the product of these crimes.

This essay was written by Tsuneishi Keiichi for publication in Sekai senso hanzai jiten (Encyclopedia of world war crimes) (Bungei Shunju, 2002), edited by Hata Ikuhiko, Sase Masamori, and Tsuneishi.

Tsuneishi Keiichi is a Kanagawa University professor specializing in the history of science, and Japan’s leading specialist on biological warfare and Unit 731.

Translated by John Junkerman, a documentary filmmaker living in Tokyo. His most recent film, “Japan’s Peace Constitution,” will be distributed in North America by First Run Icarus Films. He is a Japan Focus Associate. Posted at Japan Focus November 20, 2005.

Tsuneishi Keiichi, 731 Butai: Seibutsu heiki hanzai no shinjitsu (Unit 731: The true story behind the biological weapons crimes) (Kodansha, 1995). Tsuneishi Keiichi, Igakushatachi no soshiki hanzai (The organized crime of medical practitioners) (Asahi Shimbun, 1994; reprinted 1999). Kobayashi Hideo and Kojima Toshiro, eds., 731 saikinsen butai: Chugoku shin shiryo (The bacteriological war unit 731: New Chinese documents) (Fuji Shuppan, 1995). Tanaka Akira and Matsumura Takao, eds., 731 Butai sakusei shiryo (Documents produced by Unit 731) (Fuji Shuppan, 1991). Tsuneishi Keiichi, Mokuteki: Ishii (Target: Ishii) (Otsuki Shoten, 1984).

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Anthrax: A disease of biowarfare and public health importance

Correspondence to: Ajay Kumar Goel, MSc, PhD, Biotechnology Division, Defence Research and Development Establishment, Ministry of Defence, Jhansi Road, Gwalior 474002, India. ku.oc.oohay@37leogka

Telephone: +91-751-2233742 Fax: +91-751-2341148

Bioterrorism has received a lot of attention in the first decade of this century. Biological agents are considered attractive weapons for bioterrorism as these are easy to obtain, comparatively inexpensive to produce and exhibit widespread fear and panic than the actual potential of physical damage. Bacillus anthracis ( B. anthracis ), the etiologic agent of anthrax is a Gram positive, spore forming, non-motile bacterium. This is supposed to be one of the most potent BW agents because its spores are extremely resistant to natural conditions and can survive for several decades in the environment. B. anthracis spores enter the body through skin lesion (cutaneous anthrax), lungs (pulmonary anthrax), or gastrointestinal route (gastrointestinal anthrax) and germinate, giving rise to the vegetative form. Anthrax is a concern of public health also in many countries where agriculture is the main source of income including India. Anthrax has been associated with human history for a very long time and regained its popularity after Sept 2001 incidence in United States. The present review article describes the history, biology, life cycle, pathogenicity, virulence, epidemiology and potential of B. anthracis as biological weapon.

Core tip: Anthrax is primarily a zoonotic disease which is caused by Bacillus anthracis ( B. anthracis ) and for human it has both, public health as well as biodefence importance. Anthrax has been known since ancient times; however it acquired attention as biological warfare disease after 2001 incidence in United States. B. anthracis is supposed to be the most potent BW agent because of its hardy spores, various modes of infection and high mortality rate. Understanding about the life cycle, virulence, pathogenicity and detection and diagnosis of B. anthracis is important to curb the disease.

INTRODUCTION

Bacillus anthracis ( B. anthracis ), the causative organism of anthrax is a Gram-positive spore forming bacillus commonly found in soil of endemic areas. Anthrax is a zoonotic disease which is mainly associated with herbivores and domestic animals. The disease occurs regularly in countries where widespread vaccination of animals is not practiced. Human anthrax is less common and usually spreads to human populations through close occupational proximity to infected livestock by handling infected domestic animals including cattle and goats or their products like skin, meat, hides and bones. This bacterium can infect humans by cutaneous, gastrointestinal, or respiratory routes[ 1 ]. B. anthracis exists in two forms, vegetative cells (inside the host) and spores for persistence in the soil or environment[ 2 ]. In the soil, B. anthracis is generally found in endospore form where it can remain viable for decades in this form. As B. anthracis forms spores that can be aerosolized and sprayed to spread disease, the potential use of this bacterium as a bioterrorism agent has long been suspected. However, the events in 2001 have confirmed that bioterrorism is no longer a threat but a reality[ 3 ]. Owing to its highly pathogenic nature and spore forming capability, B. anthracis is considered as one of the most important biological warfare agents[ 4 , 5 ].

There are two major virulence factors in B. anthracis , poly-γ-D-glutamic acid capsule and a tripartite toxin[ 6 ]. Pathogenic B. anthracis bacteria produce capsule which mimics the immune system of host by masking the bacteria from macrophages[ 7 ]. The tripartite toxin of anthrax consists of three independently secreted proteins, i.e ., protective antigen (PA), lethal factor (LF) and edema factor (EF)[ 8 , 9 ]. Anthrax toxin is a binary A-B toxin, where PA acts as the binding (B) domain and LF and EF act as active (A) domains individually to form the binary toxins lethal toxin (LTx) and edema toxin (ETx), respectively[ 10 ]. After ingestion or coming in contact with skin lesions, bacteria multiply and within a few days or weeks cause the death of human or animal host.

Anthrax is not a major issue of health in developed countries as only a few incidences are reported from such countries. However, for developing countries whose economy is mainly agriculture dependent, cutaneous anthrax is still a major concern of health. India ranks first in having the world’s largest livestock population. Therefore, animal anthrax is common in several regions in India. However, only a few intermittent cases of human anthrax are reported from the Southern states[ 11 ]. Human cutaneous anthrax is a concern of public health in some states like Orissa and Andhra Pradesh[ 12 ].

HISTORY OF ANTHRAX

Anthrax, caused by B. anthracis is a highly contagious and fatal. Anthrax has a long association with human history and was known in Europe (1190-1491 BC) and China (3000 BC). Anthrax was described in the early literature of the Greeks, Romans and Hindus. The name anthrax was derived from the Greek word “anthrakis” which means coal because coal black skin lesions are formed in cutaneous form of anthrax. The description of fifth plague of Egypt, an epidemic of ancient Egypt in the book of Genesis (1491 BC), which exterminated the Egyptian livestock including cattle, sheep, goats, camels, horses and donkeys without affecting the Israelites livestock, may be due to anthrax. The disease described by Virgil (29 BC) in his third Georgics (selection of poems on agriculture and animal husbandry) seems to be anthrax in domestic and wild animals as it was an economically important agricultural disease in Europe during the 16 th to the 18 th centuries[ 13 ].

In 19 th century, research on anthrax led to a lot of medical developments. In 1850, Pierre Rayer first described filiform bodies (small rods, about half the length of a red blood corpuscle) in the blood of sheep that had died due to anthrax. Casimir-Joseph Davaine in 1863 suggested that the “corpuscles” were the etiology of anthrax that could be transmitted to sheep, horses, cattle, guinea pigs, and mice by subcutaneous inoculation of infected blood[ 14 ]. Tiegel and Klebs in 1864 demonstrated that anthrax-infected blood, if filtered through a clay candle (bacterial filter), lost its infectivity, while the deposit on filter remained infective[ 15 ]. These observations in absence of culture of the organism strongly supported the concept that the causative agent of anthrax was a living organism that multiplied in the body, invaded the blood stream, and produced death by septicaemia. Robert Koch derived his three postulates for germ theory of disease considering anthrax as prototype. In 1876, he conclusively proved that B. anthracis was the etiological agent of anthrax by applying his postulates for the first time during his research in Wollstein, Germany[ 16 ]. Thus, anthrax was the first disease whose causative agent was established as microbial agent. After isolating the anthrax bacteria from skin lesions of sheep, he obtained the pure cultures by growing the bacilli on the aqueous humor of ox’s eye, and injected the bacteria into healthy sheep. He performed another experiment by growing pure cultures of rods from the aqueous humor of an ox’s eye. By studying, drawing and photographing these cultures, he recorded the multiplication of the bacilli and found that under unfavourable environmental conditions, especially under conditions of oxygen deprivation, they produced round spores within themselves. The spores return to bacilli when growth conditions are favourable, proving the spore formation as self-protective mechanism of B. anthracis . Thus, by now it was clear how certain pastures or agriculture areas became dangerous. When any animal dies from anthrax infection, the infected blood and body fluids comes out in soil from the natural orifices of animal. The bacteria, which are in the vegetative form in the blood, convert into spores on exposure to air. These spores are extremely resistant to natural conditions and could remain dormant in the soil for decades. These spores remain available to cause new infections among susceptible animals that graze in the field.

Pasteur et al[ 17 ] proved the buried cadavers of anthrax infected animals as important origin of new infections. They further revealed that spores from buried soil could be transported to the upper surface by the activities of earthworms[ 18 ]. He also confirmed Koch’s discovery of the anthrax germ. He found that chickens were immune to anthrax, and postulated that it was because of high body temperature (43 °C-44 °C) of chickens. On lowering the body temperature to 37 °C, chickens became susceptible to anthrax. For vaccination, Pasteur heated the anthrax germs and inoculated 25 sheep. He used the heated anthrax bacteria to inoculate sheep and found that all sheep survived (only one pregnant sheep died due to some other complications), whereas all un-inoculated sheep died after one or two days of challenge with virulent B. anthracis . Pasteur proved that the weakened anthrax lost its virulence but still could confer immunity and this technique was termed as “vaccination”. Thus, first live bacterial vaccine was developed for anthrax by Pasteur et al[ 17 ]. During 1876-1877, a devastating anthrax outbreak affected several sheep and cattle in France’s livestock. By that time, rod-shaped B. anthracis was established as the causative agent of anthrax by Robert Koch. However, still many people believed that instead of bacterium itself, some toxic substance produced by B. anthracis was causing the disease. But, Pasteur finally proved that anthrax was caused by living B. anthracis and not by some toxic substance.

Anthrax was also known as woolsorters’ disease. Prior to 1837, no specific disease had been associated with wool. However, after that a large number of cases occurred in and around Bradford, England and the name Bradford disease became synonymous with woolsorters’ disease. In 1879, Bell proved that woolsorters’ disease (now inhalational anthrax) was due to anthrax[ 19 ]. This led to institution of Bradford rules which in 1897 became law. Consequently, incidences of inhalation anthrax among sorters decreased significantly. In 1913, Eurich found that blood contamination was the important factor in woolsorters’ disease[ 20 ]. Blood seemed to serve as a glue to bind anthrax spores to the raw product. Washing of wool removed soil, dried serum and blood but anthrax spores remained adherent. Elimination of inhalation anthrax as an industrial hazard followed passage of the Anthrax Prevention Act in 1919. This law mandated the construction of a decontamination station in Liverpool whereby all dangerous wool and hair products entering England were disinfected with formaldehyde[ 21 ].

During 1979-1980, the world’s largest ever recorded outbreak of anthrax occurred in Zimbabwe during the civil war. In a two-year period, over 9400 cutaneous anthrax cases, including 182 fatalities were reported. Before the war, anthrax was endemic in Zimbabwe and only a few cases of anthrax were reported. Number of human anthrax cases increased significantly during this period because lack of food due to civil war in country forced people to handle and eat anthrax infected animals. Anthrax being a zoonotic disease, it first appeared in cattle and then spread in human population in all the affected areas of Zimbabwe.

Anthrax has been supposed to be developed for use as a bioweapon during world war-1 and world war-II. Recently, in 2001, envelopes containing the B. anthracis organism were sent through the mail to different dignitaries in United States affecting 22 people. This was considered as an act of bioterrorism[ 3 ].

BIOLOGY OF B. ANTHRACIS

B. anthracis is a Gram positive, rod-shaped, aerobic, facultative anaerobic, sporulating, capsulated bacterium. It measures 1-1.2 μm in width and 3-5 μm in length. Under microscope, it appears as chain like structure. Though an aerobic organism, yet B. anthracis can survive in anaerobic environment because of its property of sporulation. In fact, it can survive for several years in soil, air and water in the form of spores. Unaffected to harsh environment, spores are resistant to high temperature, pressure, pH, chemicals, UV and deficiency of nutrients[ 22 - 24 ]. The capsule is composed of γ-linked poly-D-glutamic acid which gives mucoid appearance to the colony. Formation of capsule decides the virulence of bacteria. The capsule itself is non-toxic and doesn’t provoke immune system of the host. However, it contributes significantly in establishing the infection, once the organism escapes phagocyte action, later phase of disease is controlled by anthrax toxin[ 25 ].

Pathogenic strains of B. anthracis harbour two virulent plasmids[ 26 ]. Plasmid pXO1 carries toxins encoding genes and plasmid pXO2 carries capsule encoding genes. Size of pXO1 is 184.5 kb that harbours three structural genes, pag (coding for PA), lef ( coding for lethal factor ) and cya , coding edema factor[ 1 ]. Plasmid pXO1 also encodes atxA gene which regulates the expression of gene encoded on pXO1 and pXO2 . Another plasmid pXO2 is 95.3 kb in size and carries the genes for capsule production, degradation and regulation. Genes capB, capC and capA code for capsule synthesis, and gene dep codes for its degradation[ 1 ]. A gerX operon is also present on plasmid pXO1 and its deletion affects the germination of spores in macrophages. The operon codes for three proteins GerXA, GerXB and GerXC. These proteins are supposed to form a receptor, which specifically detects germinant within the host[ 27 ].

POTENCY OF BACILLUS ANTHRACIS AS BIOWARFARE AGENT

Anthrax was linked to soil contamination long before the identification of B. anthracis as its causative agent[ 14 , 16 ]. Spores can resist prolonged exposure to stress as desiccation, solvents and extreme temperature, pressure, pH, ultraviolet and ionizing radiation[ 28 , 29 ]. Spores of Bacillus genus are known to have a half life of about 100 years[ 30 ]. Spores are dormant form of the bacterium which returns into vegetative form on receiving the signals for germination. The surprisingly resistant spores have earned the status of potential bio-terror weapon for anthrax. The possibility to create aerosol from spores makes B. anthracis a lethal biological weapon. All the attributes of spores: high resistance to temperature, pressure, pH, ionizing radiations and half life of 100 years make them a suitable bio-terror agent. After production and purification, anthrax spores can be stored in a dry form which remains viable for decades. Spores may survive in the water, soil and on surface for several years. Inhalation of spores causes inhalational anthrax which is the most dangerous form of disease. Inhalational anthrax is dangerous for obvious reasons as initial symptoms resemble to that of flu, making its early diagnosis difficult; by the time disease is correctly recognized it’s too late.

The use of microorganisms as a means of waging war or as bioterror agents is becoming a real possibility now around the world. Any biological agent from a large gamut of human infection causing pathogens could be considered a potential biological weapon. However, only a small number of these agents fulfil the desirable criteria like ease of cultivation and dispersal or dissemination for recognition as possible biological weapons. Anthrax spores pose the biggest bioterrorism threat because it is easier to produce and preserve them. Anthrax spores have already been used in United States and in future also it is most likely preferable agent to be used for biothreat because of high case fatality rates, rapid transmission by aerosol and its stability in the environment. The release of any bio-warfare agent by a militant or miscreant would likely be silent and untraceable or nearly so. Therefore, of the recognized possible biological weapons, anthrax bacilli are rated the most lethal.

Naturally, anthrax is a zoonotic disease, which primarily occurs in animals and then spreads to human. Several animal species like cattle, goat and sheep are susceptible to this disease. A major public health preparedness challenge is increasing the importance of recognition of individual, potential sentinel cases of biothreat agent disease. According to CDC norms, B. anthracis is placed in high priority- Category A due to its ease of dissemination, high mortality rates, epidemic potential and special preparedness it requires. In 2001, mails deliberately contaminated with B. anthracis spores were used to terrorize people and subsequently research for the development of anthrax vaccine speeded up. Moreover, each category A biothreat agent has its unique clinical and diagnostic features and no single system can meet the challenges of all the agents. Besides, anthrax is still a concern of human as well as veterinary public heath in several states of country like India. Bioterrorism itself is an emerging problem for public health. Hence, it is not possible to look into bioterrorism and public health separately. Rather, it is the need of time to give more emphasis on such diseases which have both the potential.

DOSE-RESPONSE RELATIONSHIP

The information on dose-response relationship is prerequisite for assessment of risk of any biothreat agent. The LD 50 of human inhalational anthrax is not known, but has been estimated from the animal studies and disease outbreaks. After conducting experiments on 1236 cynomolgus monkeys ( Macaca fascicularis ), Glassman estimated the median lethal dose to be 4130 spores with 95%CI range of 1980-8630[ 31 ]. Further, he suggested that LD 25 was associated with a 10-fold decrease in dose i.e ., 413 spores. In 1957 in Manchester, 16 susceptible workers were exposed to B. anthracis in a goat hair processing mill and 4 persons were infected. Based on the 8-h inhaled dose, LD 50 of B. anthracis was estimated to be 6200-22000 spores[ 32 ]. The infectious dose for inhalational anthrax in 50% of susceptible human population (ID 50 ) was estimated to be 8000-50000 spores by biodefense experts from the United States Army Institute of Infectious Diseases (USAMRIID, Fort Detrick, MD)[ 33 ]. In 1998, a panel of seven subject matter experts on anthrax calculated the ID 10 , ID 50 and ID 90 as 1000-2000 spores, 8000 to 10000 spores and 50000 to 100000 spores, respectively[ 34 ]. Another group extrapolated the lethal dose (LD 50 ) values of 4100 spores[ 31 ] and 8000 spores[ 33 ] and suggested an LD 10 of 50 or 98; an LD 5 of 14 or 28, an LD 2 of four or seven, and an LD 1 of one or three spores[ 35 ]. Although they did not establish the validity of extrapolation, yet they cautioned about the low number of spores.

Theoretically, even a single spore of B. anthracis can cause anthrax. However, in the low dose range, there is high uncertainty between the dose-response relationships of aerosolized B. anthracis for human. Recently, on the basis of experimental data on primates and epidemiological data of human anthrax, a new quantitative model known as Exposure-Infection-Symptomatic illness-Death (EISD) has been suggested for the dose-response as well as time course of pulmonary anthrax in human[ 36 ]. According to this model, the ID 50 , ID 10 and ID 1 of B. anthracis spores were 11000 (95%CI: 7200-17000), 1700 (1100-2600) and 160 (100-250), respectively. The ID 50 (7200-17000) and ID 10 (1100-2600) confidence ranges produced by this model were remarkably consistent with the corresponding ranges produced by an expert panel surveyed in 1998, i.e ., 8000-10000 and 1000-2000, respectively[ 34 ]. The confidence range of ID 1 from 100-250 spores as suggested by this model indicates that a threshold of 600 B. anthracis spore to human infection is underestimated and infection by even a single spore is overestimated in the literature. This model also suggested the median incubation time from exposure to onset of symptoms. For exposure with ID 50 of B. anthracis spores, it was 9.9 d with 95%CI of 7.7 to 13.1 d, where as for ID 10 and ID 1 , it was 11.8 (95%CI: 9.5-15) d and 12.1 (95%CI: 9.9-15.3) d, respectively.

DIFFERENT STRAINS OF BACILLUS ANTHRACIS

Three well known strains of B. anthracis are Ames, Sterne and Vollum. Ames is a well studied, highly virulent strain containing both plasmids, i.e., pXO1 and pXO2 . Originally it was isolated from a dead cow in Texas in 1981. Its geographic region is United States and United Kingdom. Another isolate of Ames strain is Florida which was first isolated from a victim of anthrax attack in 2001[ 37 , 38 ]. B. anthracis Sterne is a toxigenic but avirulent strain as it carries the anthrax toxin plasmid pXO1 but lacks the capsule forming plasmid pXO2[ 39 ]. This strain is generally used for vaccine development for animals. Its geographic region is in Canada[ 37 , 38 ]. In contrast to Sterne, Pasteur strain carries pXO2 plasmid but not pXO1. Vollum is low virulent strain used in research studies and is found in the United Kingdom, Spain and Zimbabwe[ 37 ]. Along with Vollum and Sterne, strain V770 is also used for toxin production and various research related studies.

B. anthracis belongs to Bacillus cereus sensu lato group, shared by six other species including B. cereus , Bacillus mycoides , Bacillus pseudomycoides , Bacillus thuringiensis , Bacillus weihenstephanensis , and Bacillus cytotoxicus [ 40 ]. B. cereus primarily causes foodborne illness. Besides, B. cereus is considered as an opportunistic pathogen that can cause wound infections, endocarditis and urinary tract infections in humans. Recent studies indicate that a Bacillus species other than B. anthracis can cause anthrax-like disease and a few B. cereus strains have been found to be associated with “anthrax like” infections in human[ 41 , 42 ]. In India, a B. cereus strain TF5 was isolated from the tissue fluid of cutaneous anthrax-like skin lesions of a human patient from an anthrax endemic area in India[ 43 , 44 ]. The strain harboured a PA gene, however, the pXO1 or pXO2-like plasmids were not present. Exoproteome analysis exhibiting qualitative and quantitative differences between the two strains indicated an altered regulatory mechanism and putative role of S-layer protein and sphingomyelinase in the pathogenesis of strain TF5[ 43 ].

EPIDEMIOLOGY OF ANTHRAX

B. anthracis bacteria are very fragile and susceptible to disinfectant or exposure to moderate temperature. However, B. anthracis vegetative cells convert into spores on exposure to air. These spores are highly resistant to heat and to most of the disinfectants. Therefore, post-mortem of anthrax infected animals is never recommended to avoid the exposure of bacteria to oxygen. A peculiar feature of anthrax infection in animals is that blood does not clot and drains from the natural orifices like nose, mouth and bowl. This results in contamination of soil and water with bacteria which ultimately transform into spores[ 45 ]. As much as 10 9 B. anthracis bacteria may be present in the oozing blood[ 46 ]. Even the processed parts and products like leather, hides, wool, etc ., of an anthrax infected animal can carry spores for year. The spores can remain viable for a prolonged period in the soil, especially when deposited 15 cm below the upper soil levels.

Environmental and climatic factors have a great influence on the ecology of anthrax[ 47 ]. Climatic factors like rainfall and temperature play a pivotal role in incidences of anthrax cases[ 48 ]. However, it is not easy to understand the anthrax occurrence and its epidemiology due to large variations in timing of different outbreaks and associated deaths of a particular species even within a single ecosystem[ 49 ]. It has been hypothesized that some soil factors like alkaline pH, high organic content, moisture, and ambient temperature (in excess of 15.5 °C) favor the germination of B. anthracis spores into vegetative bacteria, which ultimately results into amplification of number of spores[ 22 ]. It has been observed that high pH and high contents of calcium in soil contribute to maintain the spores viable for a longer time. These soil spores cause new infections when come into contact of a suitable new host[ 22 , 50 , 51 ]. Therefore, alkaline pH of soil, high moisture and organic contents, precipitation and ambient temperature in excess of 15 °C are deciding factors for triggering a large anthrax outbreak and can be considered to predict exposure and infection risk of anthrax in a particular area[ 48 ]. During grazing, herbivores animals are most likely to be exposed to B. anthracis spores by inhalation or ingestion during grazing. It has been observed that B. anthracis bacteria need specific nutrients (animal blood, viscera) and physiological conditions and therefore it is very difficult to survive outside a viable host and convert into spores. Moreover, the vegetative cells of B. anthracis are poor competitor and are easily killed by other bacterial species outside the host in environment. Moreover, virulence of B. anthracis is reduced when grown outside the host and bacteria with reduced virulence will not lead to an outbreak[ 22 ].

According to an estimate, every year about 2000 to 20000 human anthrax cases occur globally. Apart from India and Pakistan, anthrax has also been reported from Bangladesh, Zimbabwe, United States, South Africa, Iran, Iraq and Turkey. In India, southern states are more prone to anthrax. Reports of anthrax appear almost every year from Andhra Pradesh, Tamil Nadu and Karnataka but exact figures are not available. In 1980s, there were only 2000 cases reported worldwide most of them were of cutaneous anthrax. Most of the anthrax cases recorded were from the persons involved in industrial occupations related to processing of animal parts and products like meat packing, bone meal processing, tanning of leather and sorting of hair wool[ 52 ]. Several outbreaks have been recorded in recent history. Anthrax outbreaks in animals are more prominent and common than humans. From 1991 to 1996, a total of 1612 anthrax outbreaks occurred in India. In Nepal, a total of 222 animals were affected during 19 different outbreaks in 1996[ 53 ]. In 1996, about 1570 cases of ruminant anthrax were reported in China. The death of 204 livestock in Australia was reported in 1997[ 54 ]. From 1984 to 1989, thousands of wild animals were killed in an anthrax epidemic in Namibia and South Africa[ 53 ]. In Iran, about one million sheep were killed during an anthrax outbreak in 1945. In Manchester, United States, a large anthrax epidemic occurred in 1957 in a goat hair processing plant resulting in four fatalities and nine cases[ 55 ]. In Russia during 1979, an unusual, accidental anthrax outbreak in a Soviet military laboratory of Sverdlovsk killed 68 persons out of 79 infected[ 56 ]. In Zimbabwe, 10000 cases occurred between 1979 and 1980 leading to 182 deaths. In Tibet, 507 anthrax cases resulted in 162 deaths in 1989 and in China, 898 and 1210 anthrax cases were recorded in 1996 and 1997, respectively. Between 1991 and 1995, a relatively large number of anthrax incidences was observed in Spain[ 49 , 57 ], Central America[ 57 ] and Africa[ 53 ]. In most of the cases, exposure was through cutaneous route which accounts for a total of 95% cases. The inhalational route accounts for 5% anthrax cases reported, while gastrointestinal anthrax is quite rare[ 58 , 59 ]. In 2007, a few animal and human cases of anthrax were reported from Orissa and West Bengal, India[ 60 ]. The most recent anthrax cases were found in 2010 in Bangladesh. More than 600 peoples were killed in the outbreak due to consumption of infected cattle meat[ 61 ].

As India stands first in having the largest population of livestock in the world, therefore anthrax is endemic in several regions. Based on the epidemiological study from 1991 to 2010 by National Animal Disease Referral Expert System (NADRES) in India, anthrax was found one of the ten major diseases causing deaths in livestock[ 62 ]. During 1991-2010, anthrax was reported in eighteen states of India viz ., Andhra Pradesh, Assam, Bihar, Chhattisgarh, Gujrat, Himachal Pradesh, Jammu and Kashmir, Jharkhand, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Manipur, Meghalaya, Odisha, Rajasthan, Tamil Nadu, and West Bengal. Although several regions are endemic for anthrax, yet seasonal fluctuation in the number of anthrax outbreaks has been observed. Most of the anthrax outbreaks are reported in post-monsoon season, i.e ., from July to September and November to January in different parts of India. Anthrax epidemics are generally reported between July to September and also in November and January, coinciding with the post monsoon months across the country. Several Southern states such as Andhra Pradesh, Tamil Nadu, Kerala, Karnataka and Orissa are common endemic regions with sporadic human anthrax cases reported time to time. From the Union Territory of Pondicherry, 28 cases of anthrax were detected in 1999 and 2000[ 45 ]. Both, animal as well as human anthrax cases are reported usually from certain anthrax endemic districts like Chittoor, Cuddapah, Guntur, Prakasam and Nellore of Andhra Pradesh[ 63 ]. In 2006, some cases were noticed near Narsinghpur, Madhya Pradesh also. In 2007, 20 people were affected in two cutaneous anthrax outbreaks in Murshidabad district, West Bengal. These anthrax outbreaks were caused due to slaughtering of sick cattle and subsequently handling of meat without taking proper preventive measures[ 64 ]. An increase in number of animal and human anthrax cases has been observed in this area in recent past[ 65 ]. During a tenure of 10 years, anthrax outbreak were reported at least 61 times from Orissa affecting 750 people[ 65 ]. The anthrax outbreak is a common phenomenon in this area because tribal population mainly depends on forest for livelihood. Most of the human anthrax cases occur in agricultural workers due to handling of meat or hides of diseased animal. An anthrax outbreak was reported in Orissa, India in 2013 where several people died due to consumption of infected goat meat[ 66 ]. Recently, nine cutaneous anthrax cases were reported from the tribal population of Midnapur, West Bengal in India[ 67 ].

VIRULENCE OF B. ANTHRACIS

Anthrax, being a disease of mainly herbivorous is generally prevalent in those areas where animals like cattle, horse, sheep, goat, etc ., graze. Several animal species like pigs, dogs, cats, rats and chicken are fairly resistant to anthrax. Many scavenging birds like vultures which feed on dead animals have a natural resistance to anthrax. However, such birds may disseminate the anthrax spores from infected animals through claws, beaks or feathers.

The spores of B. anthracis that can remain in the environment for a prolonged time become the infectious form of anthrax. For causing anthrax, spores first germinate, i.e ., lose their dormancy and resistance properties, regain metabolism and start vegetative growth[ 68 , 69 ]. After getting favourable environmental and nutritional growth condition, spores convert into vegetative bacteria and result in further multiplication. Human skin generally does not permit spores to invade; however, spores find access through small cuts or abrasion in skin to cause cutaneous anthrax. After entry into host, B. anthracis remains in the capillaries of invaded organs and produce lethal and edema toxins which cause the local and fatal effects of infection.

TOXINS OF B. ANTHRACIS

In soil, B. anthracis is found in its highly resistant en-dospore form and therefore, can remain live for a very long period in this state. Spores of B. anthracis can find entry in the body through lungs, skin lesion or gastrointestinal route and germinate to yield vegetative form. In case of cutaneous infections, B. anthracis comes into contact with a skin lesion, or cut. In inhalational cases, herbivorous and sometimes humans are infected after inhalation of spores. After inhalation, these spores reach alveoli of lungs through air passages. Generally, herbivores get gastrointestinal anthrax infection during grazing or browsing an anthrax spore infested agricultural field having spiky or rough vegetation. Gastrointestinal tract of animals probably gets wounds due to eating of spiky vegetation which facilitates the entry of spores into tissues and resulting in gastrointestinal anthrax.

The virulence of B. anthracis is attributed to a tripartite anthrax toxin and a poly-D-glutamic acid capsule. After entry into the host through ingestion or skin wounds, B. anthracis multiply inside the tissues of animal or human host, spread in the lymphatic system and undergo rapid multiplication. This results in production of anthrax toxin inside the body and causes death of host within a few days or weeks.

Capsule formed by the virulent B. anthracis vegetative cells helps the bacterium to evade the host immune system by impeding the ability of macrophages to engulf and destroy the bacteria[ 7 ]. Three non-toxic proteins namely PA, LF and EF of anthrax tripartite toxin co-assemble to produce a series of free or cell-bound toxic complexes[ 8 , 9 , 70 ]. Two of the toxins, LF and EF, are enzymes that modify substrates within the cytosolic compartments of host cells[ 71 ]. PA binds on the receptors of host cells and makes a pore for transportation of LF and EF to the cytosol[ 72 ]. Thus, anthrax toxin is an A-B type toxin, where PA acts as B subunit and it combines with the LF and EF, which act as A subunits to form the edema toxin and lethal toxin, respectively[ 10 , 17 ].

Anthrax PA is an 83 kDa precursor polypeptide consisting of 735 amino acids which binds to anthrax toxin receptors. There are two distinct toxin cell receptors, ANTXR1 (TEM8, Tumor endothelial marker 8) and ANTXR2 (CMG2, Capillary morphogenesis protein 2) which are widely expressed in cells[ 73 , 74 ]. Cleavage of PA by cellular proteases of the furin family, or by serum proteases generates a nicked 20 kDa fragment (PA20) at N-terminal and a 63 kDa fragment (PA63) at C-terminal[ 75 , 76 ]. The 63 kDa fragment self-associates to form a prepore which is a heptameric ring and can bind up to three copies of EF and/or LF molecules[ 6 ]. A smaller population of PA octamers (20%-30% of oligomers) is also formed, which binds up to four molecules of EF and/or LF and this structure is more stable than heptamer[ 77 ]. These hetero-oligomeric complexes are endocytosed and brought to an acidic environment, where the PA prepore makes a translocase channel after inserting into the membrane[ 78 ]. This channel is used for translocation of LF and EF into the cytosol, where by enzymatic activities they disrupt the host cell[ 79 ]. Both, LF and EF toxins reach the late endosomal compartment, where EF remains associated with the late endosomal membranes that surrounds the nucleus forming a perinuclear necklace and LF is ejected into the cytoplasm[ 80 , 81 ].

LF is a zinc dependent metalloprotease which inac-tivates the members of mitogen-activated protein kinase kinase family (MAPKK)[ 82 - 84 ]. Inactivation of three major MEKs i.e ., extracellular signal regulated kinases, c-Jun N-terminal kinases and p38 MAPKs results in impairment of various cellular processes like cell division, cell differentiation, cellular response to different types of stress and ultimately apoptosis[ 17 ].

Another protein EF is has adenylate cyclase activity. It is produced in an inactive form by the bacterium and needs calcium modulated protein (calmodulin, CaM) for its activity[ 71 ]. CaM, which acts as Ca 2++ sensor has two Ca 2++ binding sites on each of the C- and N-terminal domain. CaM binds with helical domain of EF using its N-terminal domain. EF is a highly active and its adenylate cyclise activity is almost equal to that of most active known cyclase. Activity of EF is also regulated by intracellular level of Ca ++ in a biphasic manner. Resting or little high levels of Ca ++ activate the EF via CaM, whereas high levels of Ca 2++ reduce its activity due to competition between Ca ++ and Mg ++ ion in the EF active site[ 85 ]. Because EF is associated with the perinuclear later endosomal membrane, therefore, a cAMP gradient decreasing from the nucleus to plasma membrane is generated[ 80 , 81 , 86 ]. Contrary, endogenous host adenylate cyclises generate a cAMP gradient in opposite orientation (decreasing from plasma membrane to nucleus) because these are localized on plasma membrane[ 86 , 87 ]. In anthrax infection, these two toxins are responsible for immune system failure and ultimate death of host[ 9 ].

PATHOGENESIS OF B. ANTHRACIS

Human anthrax is mainly of two types, agriculture related anthrax that occurs in a seasonal pattern, and occupation related that can occur at any time. On the basis of route of infection, there are three clinical forms of anthrax viz ., cutaneous (skin), gastrointestinal (ingestion) and pulmonary (through inhalation of spores)[ 88 ]. Recently, another type of anthrax has been identified among the heroin injecting drug users Europe[ 89 , 90 ]. The term injectional anthrax was then coined to describe this new mode of infection. A few anthrax cases have been reported due to insect bites also, which could probably be due to feeding of insect on an anthrax infected animal[ 91 , 92 ]. Once inside the mammalian host, the high nutrient content of the body triggers germination of spores, although there may be host-specific germination factors as well[ 93 ]. Sporulation does not appear to occur inside the host[ 94 ]; perhaps because once the available nutrients are depleted in the dead or dying host, the oxygen tension is too low for Sporulation[ 95 ] or possibly due to the repression of sporulation by the virulence gene regulator AtxA[ 96 ]. Spores infect macrophages at the site of entry, germinate into vegetative cells and proliferate into the tissues and start producing anthrax toxin within 3 h of spore germination[ 93 ].

Cutaneous anthrax infection starts with a small itching papule resembling an insect bite at the site of infection on skin. In a day or 2, this papule enlarges and transforms into a painless ulcer with a depressed necrotic centre and a raised and round edge. Generally, such lesions are formed with 2-5 d at the site of spore entry on skin. Finally, after 7-10 d, a black eschar, surrounded by edema is formed and this leaves permanent scar after anthrax cure[ 97 ]. Regional lymph nodes draining the infected area may be swollen and enlarged. Cutaneous anthrax infection mostly remains painless and limited to dermis. However, in certain cases it can become systemic when bacteria enter into blood stream causing bacterimia. Hemorrhagic lesions can be developed on any part of body and can be fatal in bacteremic anthrax.

Gastrointestinal (GI) anthrax occurs by eating the food contaminated with anthrax spores (most often contaminated meat). After ingestion, spores germinate and can cause lesions anywhere in the body. Based on the lesions, GI anthrax is of two types, abdominal and oropharyngeal. In abdominal GI anthrax, lesions are formed mainly in the ileum and cecum. The incubation period is generally 3-7 d. The symptoms of abdominal GI anthrax include nausea, bloody vomiting, diarrhea, abdominal pain, headache, loss of appetite and massive ascites. Another variant of intestinal anthrax is oropharyngeal anthrax where lesions are formed mainly in the oral cavity and resemble the lesions of cutaneous anthrax. Symptoms include throat pain, problem in swallowing and swelling in neck due to edema and cervical lymphadenopathy[ 97 ].

Pulmonary or inhalational anthrax occurs by inh-alation of spores into lungs. This is the most severe form of anthrax. Alveolar macrophages ingest the spores and transport to lymph nodes in mediastinum. Initially, symptoms of inhalation anthrax are like cold or flu-like with mild chest discomfort, shortness of breath, nausea and finally severe respiratory collapse. Pulmonary anthrax doesn’t cause pneumonia, but causes hemorrhagic mediastinitis and pulmonary edema. Historical, mortality was 92%, but, it can be reduced significantly if treated early as only 45% mortality was observed during the 2001 anthrax attack in United States.

Symptoms of anthrax caused by injection remain the same as in cutaneous anthrax, but there may be infection deep under the skin or in the muscle where the drug is injected. Sometimes there is redness at the area of injection. Injectional anthrax is difficult to diagnose because several other common bacteria can cause skin and injection site infections. Therefore, it is hard to treat injectional anthrax as it spreads throughout the body very fast.

There are two basic stages in the systemic anthrax infection, a prodromal and fulminant. The prodromal stage is mainly asymptomatic and generally lasts 2-4 d[ 98 ]. In this stage, macrophages engulf the spores and release to lymph nodes near the port of entry. Behaviour of macrophages and phagocytic cells is changed due to action of anthrax toxins resulting in the apoptosis and release and germination of spores into vegetative bacteria. In the fulminant stage, bacteria multiply and are distributed to different organs through bloodstream[ 99 , 100 ]. In human inhalation anthrax, treatment is started after the onset of fulminant stage because prodromal stage is largely asymptomatic. The symptoms at fulminate stage are flu-like and include labored breathing, chest pain, hypotension, headache and disorientation[ 55 , 99 - 102 ]. Bacteria secrete anthrax toxins which affect functioning of different organs like spleen, lymph nodes, liver, kidney, heart and brain. It becomes very difficult to cure the disease by antibiotic therapy at this stage and action of anthrax toxins ultimately leads to septic shock and death of host in 1-2 d.

LIFE CYCLE OF B. ANTHRACIS

B. anthracis is found in two forms, vegetative cells and spores. Adverse environmental conditions induce the sporulation and endospores are released from the mother vegetative cells. The endospores are dormant, well organized and highly resistant to various stress conditions. Therefore, these endospores can remain viable for a prolonged time in the environment and can germinate into vegetative bacteria after getting the suitable envir-onmental and nutritional requirements. During both the processes, i.e ., sporulation and germination, a lot of metabolical as well as morphological changes are observed. For spore formation, B. anthracis bacterium is divided asymmetrically by a septum into forespore (smaller portion) and mother cells (larger portion). Each portion gets a single copy of DNA. After the asymmetric division, forespore is engulfed by the mother cell with a double-membrane system. The mother cell DNA material is degraded and forespore DNA material is surrounded an inner membrane. Two peptidoglycan layers known as primordial germ cell wall (inner thin layer) and the cortex (outer thick layer) are synthesized between the inner and the outer membrane of forespore[ 103 , 104 ]. The outer membrane of forespore gets deposited by various proteins to form the coat. Thickness of spore coat varies among different species of Bacillus . In B. anthracis and B. cereus , the spore coat is compact whereas it can be distinguished in B. subtilis [ 105 , 106 ]. During spore maturation, spore acquires resistance for temperature and UV radiations and becomes dormant. Thus, spore coat imparts important functions to protect cortex and DNA of spore from various adverse conditions like environmental stress, chemicals and peptidoglycan lysing enzymes.

The life cycle of B. anthracis has been shown in Figure ​ Figure1. 1 . Animals get infected by uptake of anthrax endospores present in the agriculture fields. Inside the mammalian host, endospores find the favourable conditions like aqueous environment with sufficient nutrients and therefore, start germination[ 107 ]. During anthrax pathogenesis, transformation of spore into vegetative cell is a crucial step, because it is the vegetative form of bacterium only which forms the virulent factors, i.e ., capsule and tripartite toxin[ 27 ]. The poly-γ-D glutamic acid capsule of B. anthracis makes a complex surface of the bacterium and is surrounded by peptidoglycan layer and S-layers[ 108 ]. The capsule evades the host immune system and thus is a crucial factor for the survival of the bacteria in the host. On death, the capsulated bacteria are released with blood into the environment through natural orifices. On coming into contact with oxygen, the vegetative bacteria convert into spores and thus again infest the agriculture fields for subsequent anthrax infection in grazing animals.

Life cycle of B. anthracis. B. anthracis : Bacillus anthracis .

DIAGNOSIS OF ANTHRAX

As various outbreaks are reported time to time from different areas, there is a great need of an early diagnosis of the disease to save human and animal life. Besides, requirement of rapid and reliable detection, identification and diagnosis systems for anthrax has been emphasized by recent bioterrorism events. The early monitoring of the disease requires the detection of anthrax spores and infection both at environmental and clinical levels.

Cutaneous anthrax is diagnosed clinically employing traditional microbiological methods like gram-staining, capsule staining from the smear of the lesion or culturing of B. anthracis [ 109 , 110 ]. Several methods have been reported for isolation and identification of B. anthracis . However, on sheep Blood agar (5%) and other routine culture media, almost all Bacillus species grow well[ 111 ]. A selective media containing polymyxin-B, lysozyme, EDTA and thallous acetate was used for isolation of B. anthracis from contaminated and suspected samples[ 112 ]. Another media (bicarbonate agar) is used to induce capsule formation for subsequent identification of B. anthracis . However, there is very little utility of these selective growth media because several closely related bacteria of B. anthracis like B. cereus and B . subtilis also grow well on these media. Another undesirable feature is that it takes 18-24 h for B . anthracis to grow for characterization by various biochemical tests like catalase, oxidase, nitrate reduction, haemolysis, citrate utilization, urease[ 113 ]. Sometimes, microbiological methods like culture and Gram staining of B. anthracis do not hold good for patients who have already taken antibiotics before the sample[ 114 ]. Immunoflorescence has also been used for direct identification of B. anthracis spores[ 115 ].

Serodiagnosis is important for surveillance and confirmation of anthrax infection in animals and human. Anthrax toxin consists of PA, LF and EF. Antibodies response against these toxin components is used as a diagnostic tool for determination of past infection or vaccination.

It is well established that PA is the most important protein of anthrax tripartite toxin and it becomes the major component of anthrax vaccines including anthrax vaccine adsorbed. Therefore, antibody (IgG) levels against PA in human and animals are determined to study the host immune response to B. anthracis infection and anthrax vaccine[ 116 , 117 ]. In United States, a total of 22 individuals were identified with bioterrorism-related inhalation or cutaneous anthrax, 11 patients for each type from 4 th October to 20 th November 2001[ 118 ]. In 16 of 17 confirmed or suspected clinical anthrax patients, anti-PA IgG antibody could be detected after 11 d of onset of symptoms or probably 15 d after the exposure to B. anthracis . Antibodies against PA could be detected up to 8-16 mo in all the cases of inhalation anthrax and 7 out of 11 surviving cutaneous anthrax patients[ 118 ]. For serodiagnosis of cutaneous anthrax, an enzyme-linked immunosorbent assay was developed in India for determination of anti-PA IgGs with 99.4% specificity and 100% sensitivity[ 119 ]. A field based qualitative visual ELISA for anti-PA IgG was also developed for serodiagnosis of anthrax[ 120 ]. Results of sensitivity and specificity of visual ELISA were found compatible with the results obtained from standard ELISA measuring OD values. Likewise, a quantitative ELISA was developed for measurement of the anti-PA IgG level in human serum samples[ 121 ]. The minimum detection limits and lower limits of quantification of the assay for anti-PA IgG were 3.2 μg/mL and 4 μg/mL, respectively. The serum samples collected from the anthrax infected patients were found to have anti-PA IgG concentrations of 5.2 to 166 μg/mL[ 121 ]. CDC, United States has developed a lateral flow immunochromatographic device using colloidal gold nanoparticles for determination of anti-PA IgG in serum or whole blood[ 122 ].

However, animal studies with anthrax vaccine revealed that LF evokes higher IgG response in comparison to PA in animals[ 123 ]. In patients of natural cutaneous anthrax, immune response to LF is higher and faster than the antibody response to EF and PA, which is lower and delayed[ 124 ]. Anti-LF IgG antibodies appeared in patients just after 4 d of onset of anthrax symptoms, whereas anti-LF and anti-PA IgG could be detected after 6 d and 13 d, respectively. In a study of human cutaneous anthrax, 11 of the 17 patients had measurable IgGs against one of the three toxin components. Anti-LF IgG was found in 65% patients, while anti-PA and anti-EF response could be found only in 18% and 24% patients. The anti-LF IgG titre in all the infected patients was higher than the titre of anti-PA or anti-EF IgG. After two weeks of infection, the mean anti-LF IgG titre in all infected patients was 69.3 μg/mL, which was twice the tire of anti-EF IgG (37.4 μg/mL) and thrice the titre of anti-PA IgG (22.6 μg/mL)[ 124 ]. It was also observed that in anthrax cases, class switching of antibody from IgM to IgG occurs faster. Anti-PA IgG could be detected just after 11 d of onset of symptoms in patients with inhalation anthrax, while no anti-PA IgG response was found till 21-34 d in patients with cutaneous anthrax[ 117 ]. Therefore, it is evident that LF evokes a faster and stronger host immune response in comparison to the other two anthrax toxins, i.e ., PA or EF. Therefore, detection of anti-LF IgG in human serum can be a good marker for serodiagnosis of anthrax. For detection of anti-LF antibodies, an indirect ELISA was developed for serodiagnosis of cutaneous anthrax in human[ 125 ]. The vaccinated and cases of natural anthrax infection can be differentiated by the anti-LF ELISA because PA is the principal component in anthrax vaccine.

Rapid diagnosis of anthrax at an early stage of infection i.e ., before the appearance of symptoms can be very useful for proper medical treatment to stop the further spread of infection and accumulation of toxins. For early diagnosis, detection of anthrax toxin in serum or plasma can be a reliable marker of infection[ 126 ]. An ultra sensitive immunoassay known as European Nanoparticle Immuno Assay (ENIA) has been developed using European nanoparticle for the detection of PA in sera, which has been found 100 times more sensitive than ELISA[ 85 ]. ENIA showed good linearity for detection of PA in the range of 10 pg/mL to 100 pg/mL, whereas range of PA detection in ELISA was 1-100 ng/mL. An engineered sandwich capture ELISA was also reported for the detection of both PA as well as LF[ 127 ]. In the sandwich ELISA for PA detection, anti-PA high affinity single chain fragment antibody or receptors for anthrax toxin (ANTXR2) were used for capturing the analyte (PA), and rabbit anti-PA polyclonal serum was used for revealing antibodies. The detection sensitivity of PA by was as low as 1 ng/mL in serum. The detection sensitivity of sandwich ELISA for LF, where PA 63 was used for capturing of analyte was 20 ng/mL. Surface Plasmon Resonance (SPR) has also been found a very good technique for detection of PA from serum samples of human[ 128 ]. The SPR assay could detect 1 pg/mL of the purified PA and 10 pg/mL of PA in human serum[ 128 ].

Recently, a new method utilizing genetically modified phages has been developed for detection of pathogenic B. anthracis from clinical sources[ 129 ]. The reporter phage displays species specificity by its inability, or significantly reduced ability, to detect members of the closely related B. cereus group and other common bacterial pathogens.

Nucleic acid based detection methods have also been developed for detection of anthrax. These techniques make use of nucleic acid sequences unique to B. anthracis . The technique has gained enormous popularity for its specificity. Polymerase chain reaction (PCR) or real-time PCR amplify the specific chromosomal markers or virulence plasmids present in the B. anthracis . Such new rapid detection and diagnostic tests are important for clinicians for early identification of infection.

Anthrax, caused by B. anthracis is still an important endemic disease of public health importance in several countries of Asia, Africa and Europe. It is re-emerging in some western countries due to political unrest or changing life style (use of intravenous drugs) as evident from the recent outbreaks. In country like India, anthrax is a concern of public health as clandestinely encountering in several states like Andhra Pradesh, Kerala and Karnataka, Orissa and West Bengal. Although anthrax can be cured by prompt antibiotic therapy, yet it is fatal in several cases because of lack of proper diagnosis well in time. Among the three clinical forms of anthrax cutaneous anthrax is most frequent but can be easily cured. The other two forms, gastrointestinal and inhalational anthrax are less common but difficult to cure and have high mortality rate. Recently another form of anthrax, i.e ., injectional anthrax is also posing threats for early diagnosis and treatment. However, active surveillance, proper animal immunization and awareness can help to curb the disease. Rapid and accurate diagnosis of cutaneous anthrax is crucial for treatment well in time and making strategies for further spread and control of disease. Although a lot of molecular tests are available for anthrax, yet this is difficult to employ these systems keeping in mind the available resources at far off locations where anthrax is endemic. Therefore, rapid, user friendly, inexpensive serodiagnosis tests can be important tools for surveillance of anthrax and active surveillance can help to minimize the agriculture or occupation related anthrax.

ACKNOWLEDGMENTS

We are thankful to Director, Defence Research and Development Establishment (DRDE), Defence Research and Development Organization (DRDO), Ministry of Defence, Gwalior for providing necessary facilities and funds for this research work.

P- Reviewer: Kayabas U, Vaughan G S- Editor: Ji FF L- Editor: A E- Editor: Lu YJ

Supported by Defence Research and Development Establishment, Defence Research and Development Organization, Ministry of Defence, Gwalior.

Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

Peer-review started: July 30, 2014

First decision: August 28, 2014

Article in press: December 23, 2014

Socialism & Democracy

On the biological warfare “hoax” thesis.

Milton Leitenberg’s biological warfare hoax theory is not believable. For the past three decades, Leitenberg has paraded the thesis that the allegations of biological warfare use leveled against the United States by North Korea and China during the Korean War has all been a nefarious hoax— a grand piece of political theater— deviously orchestrated by Mao Zedong, Zhou Enlai, and the swarthy Joseph Stalin. Leitenberg’s thesis epitomizes the deeply embedded racism of America’s Cold War politics. He has enjoyed bounteous support from right-wing academia and quasi-government think tanks. The BW hoax thesis has impacted scholarship and US foreign policy, and it is a major stumbling block to improving US relations with North Korea. In this essay I will argue that Leitenberg’s thesis is a house of cards built on forged documents, false claims and fake facts.

Arrayed against the hoax thesis is the entirety of collected material evidence and eye-witness testimony. 1 That body of evidence includes the depositions of Korean and Chinese civilians who witnessed US aerial attacks during the war; 2 it includes the testimony of a British soldier of a ground deployment by US paramilitary personnel during the retreat from the Yalu River in the winter of 1950-51; 3 and it further includes the leveling of criminal sedition charges against American journalists for reporting the allegations of germ warfare. 4 Additional evidence includes the revelation of a highly advanced Japanese BW program Unit 731 during WWII located near Harbin, China which was responsible for the deaths of 400,000 Chinese and Russian nationals, the secret acquisition of this BW program by the US Army, 5 the quid pro quo granting of immunity to Unit 731 director Shiro Ishii and his subordinates from war crimes prosecution, 6 the Soviet Union’s prosecution of General Otozo Yamada at the 1949 Khabarovsk War Crimes Trial and the revelations of that tribunal, 7 the anchorage in Wonsan Harbor of US Infantry Landing Craft No 1091 described by Newsweek Magazine as the “bubonic plague ship,” 8 the strange mission of its commander, General Crawford Sams, to abduct an infected enemy soldier from a North Korean hospital bed, 9 the appearance of diseases hitherto unknown to the region, namely, pulmonary anthrax and hemorrhagic meningitis, 10 the lab reports of Chinese medical examiners published in the December, 1952 Chinese Medical Journal , 11 the confessions of 19 American pilots and crew shot down and captured behind enemy lines, 12 the mysterious and dramatic murder of CIA bio-weaponer Frank Olson, 13 and not least, the extensive findings of the International Scientific Commission (ISC) led by Joseph Needham which investigated the BW allegations and concluded unequivocally that the US had indeed engaged in germ warfare attacks by air against North Korea and China at identified locations on specific dates and times. 14

The preponderance of all this evidence is indisputable, yet the US government continues to this day to refuse to address any of this evidence case by case. The government’s defense tactic at the time (and remains today) was to lump all BW war crime evidence against it into one basket which it then ignored or dismissed as communist propaganda. There was never any attempt to refute or provide countervailing evidence of any charge in any of the specific evidence categories. Instead, the US embraced the inherently racist strategy of employing authority figures in government and academia to heap scorn upon the Chinese and North Korean accusers. Disparaging speculations regarding the motives of victims were openly aired in Congress. A systematic purging of Korean War records was secretly begun, and the national “forgetting” of the Korean War became unspoken policy. Finally, the US initiated the vigorous prosecution and the threat of prosecution against whistle blowers to silence the truth.

US denial has also consisted of a continuous disinformation campaign. The official denial mantra asserted the BW allegations were false accusations intended to smear the US. When Secretary of State Dean Acheson sanctimoniously denied any “UN Command” involvement in BW deployment, this denial served as a diversionary smokescreen for what was largely a CIA paramilitary operation outside UN Forces command. 15 The US led UN Command could claim clean hands because the dirty work was provided by outsourced CIA covert operatives.

In 1998, the false allegations claim of the US morphed into a more sophisticated version with the publication of two papers by scholars, Kathryn Weathersby and Milton Leitenberg of the Woodrow Wilson Center. 16 Leitenberg claimed that new evidence consisting of twelve documents, collectively the “Russian dossier,” allegedly smuggled from the Soviet Union Presidential Archive proved beyond any doubt that the BW allegations by North Korea and China were a complete fabrication. The communist had staged a Cold war political gambit to tar brush the US on the international Cold War propaganda front. It was a devious but failed tactic in the larger struggle between the competing hegemonic systems of communism and capitalism.

Leitenberg’s “hoax thesis” has been generously underwritten by the Woodrow Wilson Center’s Cold War International History Project (CWIHP). In 2016, Leitenberg revisited this subject for CWIHP with a second essay claiming additional documentary evidence to support his theory. 17 Documents #1-16 consist of cable correspondence between Mao, Zhou and Stalin regarding immediate measures necessary to combat the new BW threat. Document #17 and Document #20 are rambling essays by Tibor Méray, who as a young Hungarian communist journalist was sent to the front to report the Korean War from the North Korean side. The third source, Document #19, is claimed to be a posthumously discovered memoir written by Wu Zhili, a medical doctor and Director of Public Health for China’s People’s Volunteer Army (PVA) during the war.

These three sources along with the Russian dossier are Leitenberg’s sole evidence to support his hoax thesis. Leitenberg makes no attempt to address or refute any of the evidence piled up against the US by scholars Sheldon Harris, Stephen Endicott, Edward Hagerman, Peter Williams and David Wallace, or the accounts of journalist Wilfred Burchett and Alan Winnington, who covered the Korean War at the front and witnessed events first hand. Instead, he is dismissive and scornful of all evidence but his own, and further insists that his interpretation of his own documents is the only possibly true explanation of events.

However, the Russian dossier is a deeply flawed source of evidence as I pointed out in my previous article. 18 The acquisition of the 12 documents which make up the dossier is cloaked in shadow. 19 They are copies of copies of copies which cannot be temporally or materially connected to their claimed source, the Soviet Presidential Archives. The likelihood that they are complete forgeries is far greater than the slim possibility that they are actual transcripts of secret Kremlin correspondence. As I further pointed out, on the very long chance they do happen to be real, Leitenberg’s spin as to their meaning is the least likely of various possible interpretations.

In this article we will turn our attention to Leitenberg’s three new sources to see if they fare any better than the Russian dossier. We will also spend time with the International Scientific Commission report ( ISC Report ), that very difficult to find volume which has just been made available in electronic format. 20 But before beginning these exercises we should remember the context of our story.

The Korean War was the first military battleground of the Cold War. More than 4 million Koreans died in the three years of intense combat, the vast majority of this carnage was caused by US saturation bombing, fire-bombing and aerial strafing. More than 400,000 tons of explosive ordnance was dropped during the war with another 30,000+ tons of napalm. Every building north of the 38th Parallel was burnt and turned to rubble. The KPA and the Korean civilian population dug into caves and underground shelters to survive three years of intense bombings. The germ warfare attacks occurred during 1951-52.

Let us begin by looking at Leitenberg’s addendum Documents #1 - #16. Leitenberg claims these documents come from Chairman Mao’s personal archive. How he obtained them is not stated, though CWIHP does advertise on its website that any foreign scholar with access to their country’s top secret government files is welcome to apply for a fellowship at the Woodrow Wilson Center. Regardless of means, it is completely unclear why Leitenberg would believe that this collection of correspondence between Mao Zedong, Zhou Enlai, and Stalin would support his hoax hypothesis. In fact, it does exactly the opposite. These cables demonstrate just how seriously the three communist leaders take the American BW attack, and the practical measuress they rush into place to contain the assault. Let us examine this correspondence.

#1 is one of Chairman Mao’s frequent poetic exhortations to the masses, this one from 1952: “Get mobilized, stress sanitation, reduce disease, improve health, and smash the enemy’s bacteriological warfare.” On February 18, 1952, Mao received a report from Nie Rongzhen, Acting Chief of Staff of the People’s Revolutionary Military Commission. Nie’s report details that insects— spiders, flies, and fleas — were dropped by US airplanes over a wide area of North Korea controlled by PVA frontline troops of the 20th, 26th, 39th, and 42nd armies. Nie stated that experts had been sent in for field studies, and samples of insects had been sent back to Beijing for testing to determine what kinds of bacteria they were infected with. #2, Mao’s response is concise, “Please have Premier Zhou pay attention to this matter and take care of it.” Mao promptly delegates this new emergency to the very top echelon of government.

In #3, Mao details to Stalin at length about this new BW development in the war. He states that 3.4 million doses of vaccine and 4000 lbs. of insect powder have already been sent to the front. He further reveals that Japanese war criminal Shiro Ishii, and two former Unit 731 staff, Wakamatsu Yujiro and Kitano Masajo, had been testing bacterial weapons on Chinese and North Korean POWs at the prison camps on Kyoseyto (Koje) Island. Mao states this report was confirmed by a May 18, 1951 Associated Press dispatch by an American journalist. 21 Mao requested unspecified assistance from the Soviet Union.

#4 is a brief reply from Stalin to Mao which states, “We agree with the plan of measures you have proposed.... The Soviet Government, for its part, will actively support these measures.” #5 is green light instructions from Mao to Zhou to proceed with vaccine protocol in designated cities and provinces. #6 is a request for assistance from Zhou to Stalin for a nine-member team of medical specialists in epidemiology, microbiology, parasitology, and similar skills to be sent to China with all the necessary lab equipment to conduct research. #7 is a second request from Zhou to Stalin to send “pure DDT – 600 tons; live anti-plague vaccine – 20 million doses; and tetanus vaccine (typhoid fever, parasitic typhus A, parasitic typhus B, cholera) – 20 million doses.” Zhou exhorts the urgency of need by requesting his order should be delivered by airplane directly to Beijing. Zhou also makes it clear to Stalin that he expects this aid to be put on China’s bill. “I request that this order be included in the account for goods exchanged.”

#8 is a request from Mao to Stalin for more fighter jets to be deployed to airbases in China and the training of Chinese pilots to fly night and bad weather missions to shut down US air superiority and the spreading of BW germs into China. Some Korean War scholars argue that with the ground war bogged down in WW I style trench warfare by 1952, it was really the rise of the Chinese Air Force flying Soviet MIG fighter jets that turned the tide of the war and forced the US to enter seriously into truce talks. 22

#9 is the reply from Stalin to Zhou. Stalin agrees to send the 9-member epidemiology team with necessary lab equipment within two weeks. Within four weeks the Soviet Union could deliver 5 million plague vaccines, 3.8 million cholera vaccines, and 8.5 million typhoid fever vaccines. In the following month an additional 5 million plague vaccines, 3.2 million cholera vaccines and 4 million typhoid vaccines would be delivered. Additionally, 100 tons of pure DDT were being sent within the month and another 100 tons the following month. Obviously, Zhou Enlai had submitted a very large chemical and pharmaceutical order and the Soviets were scrambling to fill it ASAP.

#10 and #11 consist of brief comments by Mao on reports from the front on public health measures, vaccination protocols, and hygiene efforts. He approves the measures described in the reports and recommends a more widespread adoption across China This subject seems fairly innocuous; after all, improving public health and hygiene is an obvious step which needs to be undertaken in fighting disease epidemics, but it is in fact quite a controversial topic in Cold War scholarship. Right-wing scholars argue that the BW scare was all a ruse to institute rigorous Western public health reforms including widespread “vector annihilation” into a backward Buddhist world view of cohabitation with all creatures. They argue that the BW scare was a communist ideological ploy to radically change cultural norms throughout China. 23

#12 is a cable from Mao to Stalin informing him of the arrival in Beijing of the delegation of the International Scientific Commission. He notes the presence of the Russian commission member Zhukov-Verezhnikov, and his offer to bring in four more Russian scientists to review and organize the evidence for the ISC Report. Mao presses Stalin to send the additional specialists.

This particular cable is a lightning rod for Leitenberg. Zhukov was a renowned and highly decorated Russian scientist who was a leading researcher in many areas of epidemiology and disease prevention. He had a long and illustrious career and received many awards and commendations during his life. 24 He is most noted in the West, prior to serving on the ISC, as the expert witness on disease pathology who testified at the 1949 Khabarovsk War Crimes Trial held by the Soviet Union which convicted General Otozo Yamada, Commander-in-Chief of the Japanese occupying army in Manchuria, and his top officers for biological warfare crimes. 25

Leitenberg fingers Zhukov as the behind the scenes puppet master of the ISC. He alleges that it is Zhukov who orchestrates the fix to provide false evidence and false lab reports to dupe Joseph Needham and the other ISC members into believing the fabricated BW charges. Leitenberg produces no evidence to support this claim. Zhukov, in Leitenberg’s narrative becomes the godfather of the hoax. Leitenberg denounces him dismissively as a “KGB general.” 26

#13 This brief cable from Mao to Peng Dehuai, Commander of the PVA, commends the general for the robust mobilization effort against BW at the front. Rapid army response to BW attacks including quick site clean-up procedures, increased numbers of hygiene workers and epidemic prevention teams, more field hospitals and ambulances, mandatory inoculations, more public bathrooms, better sewage treatment and disinfection stations, more volunteer recruitment, a big push towards the extermination of insects, rodents, small birds, other potential vectors, and a massive public education effort— what is revealed in this hubbub of activity is just how nimbly the Chinese government, the PVA, and the KPA mobilized the general citizenry throughout China and North Korea in response to the BW threat.

This response was prophylactic. Through immediate preventive action China attempted to mitigate the potential effects of widespread contagion. These methods were practical, highly effective and low cost. And the results paid off very well. The truth about the American BW attacks which the Chinese, the North Koreans, the Russians, and the Pentagon all know, but nobody else seems to know or is willing to admit, is that the sustained BW assault was simply not effective. The total number of casualties has never been released by any of the principals, but apparently it was proportionately small. For the US Army, BW was a grave disappointment.

#14 and #15 are Soviet documents which do not seem germane to the subject. The last document #16 is a cable from Mao to Kim Il Sung dated November 8, 1952, informing him that China intended to release the statements of 19 American POWs who had confessed to engaging in bacterial warfare against North Korea and China. (They had previously been broadcast by radio.) He requests North Korea’s cooperation. The confessions were being released in response to complaints raised by the US in the UN general Assembly that China had compelled (brainwashed) American POW’s to make false statements.

There is nothing in any of these correspondences which Milton Leitenberg parades about as evidence of a grand BW hoax that even remotely affirms his thesis. The emergency measures undertaken by North Korea and China to defend themselves against the sustained American BW attack are revealed in these documents as completely genuine and carried out with the utmost urgency. Even though these measures were low budget prophylactic strategies, they worked very effectively. The effectiveness of this defense was due to tremendous wartime mass mobilization in both countries, the competence the leadership brought to the task, and the tremendous public support that allowed for great sacrifice and loss of life during the war years. There is no evidence of a grand hoax by North Korea, China or the Soviet Union contained in these documents.

Let us now turn to the two essays by Tibor Méray attached to Leitenberg’s 2016 paper. Document #17 consists of 12 articles published sequentially by the Parisian daily Franc-Tireur between the 6th and 19th of May, 1957. 27 Document #20 is titled “Germ Warfare: Memories and Reflections,” and is sourced to Milton Leitenberg’s personal papers. It is the English translation of a talk Méray gave in June, 2000 at the Woodrow Wilson Center. 28

In May of 1951, Tibor Méray was a 23-year-old aspiring writer and Communist Party member who covered the art & culture beat for the Hungarian Communist Party daily, Szabad Nép . Without forewarning, Méray was sent to cover the Korean War peace talks in Panmunjom. He arrived like a deer in headlights speaking no Korean, no Mandarin, a little English and some French, but regardless he was promptly embedded with the North Korean PLA delegation. There he met Wilfred Burchett and Alan Winnington, two Western correspondents embedded with the Chinese PVA delegation. The PVA negotiators usually had better information than their KPA counterparts so Méray had to frequently go to his senior colleagues for updates. The three men bonded across two years of negotiations and shared battlefield experiences. Méray’s dispatches distributed throughout the global Soviet press duly reported the BW allegations on which he was briefed.

Méray returned to Budapest after the war. He supported the reform government of Imre Nagy in which the intelligentsia placed high hopes, but Nagy’s reforms were subverted by a rival Party faction. In 1956, amidst a worker and student rebellion in the streets of Budapest, Khrushchev sent in the tanks to put down the revolt and install a government more to the liking of the Soviet Union. Méray fled Hungary and lived abroad for the next thirty-five years. Several friends and former colleagues were sent to prison, or executed. He was forever embittered by this betrayal of the intelligentsia class, and became ardently anti-Communist and a harsh critic of the Soviet Union and the Hungarian socialist government.

Méray’s falling out with Burchett, however, occurs after the Korean War. The two journalists meet again in a 1954 lunch reunion in Budapest which included Méray's friend and mentor, Miklos Gimes. Later recalling this meeting in his autobiography, At the Barricades , Burchett expresses little sympathy for the pampered life of the Hungarian intelligentsia, and their naive view of the stakes in the Cold War struggle between East and West. Without mentioning him by name, Burchett rebukes Méray for cowardly scampering to Paris in the 1956 uprising and not fighting in the street for what he believed.

On Burchett is Méray’s hurt and angry reply to the double betrayal of the Communist Party and of his one-time friend and colleague with whom he shared many battlefield close calls. This volume reprises both of Leitenberg’s texts, and is superior for it reveals Méray’ personal motivations for his modified views on the Korean War BW issue. Méray cryptically opens his book with the sentence, “Had you not written those sixty-five lines, Wilfred, I would not have set out to write this book.” From there, Méray’s book includes a rant of fault-finding, conjecture, and character assassination regarding Burchett, a few stories from the war front for color, the reworked Leitenberg excerpts, and a great deal of wallowing in doubt.

Following his flight from Hungary, Méray takes his Korean War BW stories to six eminent French scientists. These pillars of the French Academy, each in turn, drill into a befuddled Méray the fundamentals of Cartesian doubt. If Méray was not a lucid and uninterrupted witness to the entire chain of BW discovery, that is— from the moment of deployment, through sample collection, through delivery to the lab, through culturing of bacilli, through identifying and counting microbes under a microscope, through writing the lab report— how could he possibly be certain the declared result had not been compromised?

But this scenario is completely absurd, and is not how science operates in the real world. In the professional practice of science, if one is required to pee in a jar for a drug test, the policeman witnessing your sample-taking is not the lab technician writing up the report which will convict you in court. There are many roles in this chain and each actor is expected to fulfill their allotted task in a professional manner. Medical science is built upon the mutual trust of its participants in their honesty and methodology. The scientific process is highly compartmentalized.

At no time in any of his Korean War correspondence or subsequent writings does Méray claim to have discovered deliberate deceit. At no time does he say that he has been lied to by his North Korean and Chinese hosts. At no time does he claim the BW allegations were false. Méray comes to despise communism and the Stalinist state, and he readily admits his opinion regarding BW has been tainted by his disillusionment and feelings of betrayal. But after all that, Méray’s claim is simply that he cannot be sure, that he has doubts. 29 This admission of doubt from a deeply wounded and embittered soul about events which transpired more than half a century earlier is hardly substantiating evidence of some concocted BW hoax. Méray’s testimony offered as evidence for a grand theatrical BW hoax is completely ludicrous. It only succeeds in making Leitenberg’s hoax thesis increasingly farfetched.

The most curious of Milton Leitenberg’s 2016 documents is the purported memoir of Wu Zhili. In his role as Director of the PVA Health Division, Wu Zhili was at the center of China’s campaign to fight the American BW attack, and to implement public health measures to reduce widespread contagion. His testimony, were it authentic, would be highly significant for establishing the truth or falsehood of the BW allegations. It is the first document from a Chinese source which appears to question the official Chinese and North Korean narrative of the BW charges against the US, and therefore it deserves close scrutiny.

In the opening statement, the document poses a question which it then answers very concisely, “[H]ow indisputable is the bacteriological war of the American imperialists? The case is one of false alarm.” The essay then proceeds to make the case for a lack of physical evidence of BW pathogens, such as anthrax, plague and cholera in the samples of flea and fly vectors recovered in the battlefield environs. It then claims that the insects recovered were native species of snow fleas, not introduced ones from afar, and these local insects are not carrying any exotic diseases. It goes further to lament the lack of corpses for forensic autopsy to confirm disease outbreaks. Therefore, in all three critical areas of disease pathology— the collection in the field of diseased vectors, the laboratory analysis of pathogens, and the autopsy of victims— the research of the Chinese medical staff has drawn a blank in establishing evidence for the American BW attack.

The essay then delves into the political issues involved as China and North Korea have already denounced the US attack to the world, and now their scientists cannot produce the evidence. What to do with the imminent arrival of the ISC investigators? The author describes with trepidation his summons to deliver the bad news to General Peng Dehuai at PVA Command. He fears his role melodramatically, “my head will be chopped off.” However, Peng, in spite of his displeasure at receiving such bad news, shows his pragmatic side by ordering the author to use this opportunity to launch widespread public health measures of hygiene and vector control in Korea and China. 30

According to Leitenberg’s narrative, this essay was discovered posthumously in Wu’s personal papers, and published in 2013, seven years after his death, in the journal, Yanhuang Chunqiu , an obscure academic publication of the Chinese Academy of Art. 31

The first question which arises is the authenticity issue. Is this truly the “memoir” of Wu Zhili? As with the Russian dossier, once again Leitenberg has produced a critical document with an untraceable origin. Who “discovered” this document? Where is the original manuscript? Is the original written in Wu’s handwriting? Who delivered it to the editors at Yanhuang Chunqiu ? Where is the editorial board correspondence which would surround such a controversial topic? Are there any family members or living colleagues who can corroborate the content from personal experience or private discussions with the author? Just like the Russian dossier, the authenticity shadow looms heavy over this document. It seems remarkably convenient that it should appear from a dead author out of an evidence vacuum to fill in the exact blanks necessary to patch together Leitenberg’s hoax thesis.

The second glaring flaw of this document is the accuracy of claims made by the author regarding the lack of BW evidence. These assertions are directly contradicted by the evidence collected and published in the ISC Report. For example, in Appendix AA, “Report on the Occurrence of Respiratory Anthrax and Haemorrhagic Anthrax Meningitis following the Intrusion of U.S. Military Planes over Northeast China” (ISCC/5), five cases are discussed with accompanying lab diagnosis and autopsy reports. 32 In Appendix FF, “Memorandum on Acute Encephalitis – A New Disease in Shenyang (Mukden) and its Neighborhood, Produced by the Intrusion of Bacteria Disseminating U.S. Planes” (ISCC/6), a 73% mortality rate within 48 hours is stated, and eleven autopsy reports are discussed. 33 The ISC Report is quite thorough in presenting the pathology of each investigated incident, and there are many examples of concise pathology discussions which directly contradict statements of their lacking in the purported Wu Zhili memoir. There are also extensive photographic images of diseased human organs and brain tissue with slide specimens of isolated disease samples. On the grounds of factual evidence, the document presented by Leitenberg is completely misinformed.

However, the most startling claim in this document is that two condemned prisoners were inoculated with plague bacilli in order to have autopsy evidence to present to the ISC. This admission, which is made in an off-hand manner, amounts to a serious denunciation of the PVA for adopting the same criminal tactics used by the Japanese Army Unit 731. By making this charge, the author deliberately undermines the moral higher ground upon which the Chinese Communist Party had built its loyalty with the masses. The CCP is dragged down into the same immoral cesspool as the Japanese invaders. This is not a credible narrative given China’s very recent experience with Japanese bio-terrorism indelibly stamped into the national historical memory. It is not believable that Wu Zhili would so incautiously denounce his colleagues and the Party with this pernicious slander. There is no supporting historical evidence for this claim. Given this careless defamation, who could believe this untraceable document was actually written by Wu Zhili?

Wu edited two anthologies of medical papers. He was the lead author and editor of the volume, Summary of Health Service in the War to Resist US Aggression and Aid Korea . This is a very thorough account of the medical corps logistical work to set up public health services during the Korean War. Regarding the US bacteriological attack, Dr. Wu states, “Our experience is that germ warfare is not terrible, as long as the organization is well-conducted with fast testing and early diagnosis, vaccination is carried out strictly and repeatedly, the enemy’s agents are discovered and extinguished quickly, and a tight quarantine is in place. These are effective anti-epidemic measures to prevent bacterial weapon damage.” 34

Wu Zhili is the author of Autobiography of a War Doctor . This book is actually a double volume also containing Proud Memories , the autobiography of his wife, Zhang Yangfen, who was a medical education expert. This double volume is the true “memoir” of a remarkable medical couple who were at the very forefront of the campaign to revolutionize China’s public health system. Their lives were heroic in every sense of the word through their idealism, their work ethic, their commitment to the Chinese Revolution and to the new communist state. Nowhere do they claim that the American BW attack was a “false alarm.” The Wu Zhili “memoir” that Leitenberg bandies about appears to be a fabrication. 35 In my view, this document, like the Russian dossier before it, is a fraud.

While I maintain that the purported Wu Zhili memoir is a planted fake, a new chapter in this story has recently come to light in a privately circulated essay by historian Stephen Endicott. Endicott and Edward Hagerman co-authored, The United States and Biological Warfare: Secrets from the Early Cold War and Korea . This book is a meticulously researched indictment of the secret US germ warfare campaign against North Korea and China. Endicott and Hagerman visited China in 1997 arranging interviews and collecting documents as a prelude to publication of their book. While in Beijing they requested an interview with Wu Zhili who agreed on the condition that permission was granted from the PVA. This permission was not forthcoming, so the interview could not take place.

Endicott speculates that Dr. Wu wrote this essay in response to the denied interview, with the caveat, “if it is genuine.” If we entertain the possibility that it might be genuine in an honest attempt to better understand this chapter of history and the private motives of individuals, the text suggests that Wu may have written the paper out of anger or feelings of humiliation at having been denied by functionaries an international platform to tell his side of the BW story. Also, we might inquire, how good was Dr. Wu’s memory of war events after four and a half decades? Endicott suggests that Wu stuck the essay in a drawer and forgot about it. Had he rediscovered it later he might have had second thoughts, but how many writers go through old file drawers?

The opinions expressed by the text’s author regarding the BW campaign sharply differ from those of Peng Dehuai, and the CCP leadership, Nie Rongzhen, Zhou Enlai, and Mao Zedong. Endicott concludes that Dr. Wu’s view was less informed. Endicott suggests that had he been aware of subsequent evidence, statements and interviews both from American and Chinese participants, i.e., historical hindsight, he might have had a different opinion. Wu was privy to the medical evidence, but what did he know regarding the pilot confessions, or the flight data, or events away from his location at the front?

To that observation I would add that,unlike the four political leaders, Wu Zhili is a trained scientist. He demonstrates the same professional skepticism as Tibor Méray’s six Cartesian academics. He further understands the disease pathology better than the others. The simple fact that widespread pandemics did not break out across China and North Korea leads him, the scientist, to question his initial premise. However, his conclusion, that it didn’t happen (“false alarm”) is mistaken. This conclusion directly contradicts what Wu Zhili states very clearly in his Summary of Health Services, that the BW campaign wasn’t effective because of the defensive countermeasures undertaken.

Apparently, it is not that easy to infect a large population over a broad area with lethal diseases, if your intended victims are aware of your actions and can take precautionary countermeasures. 36 The technology in 1951-2 of spreading disease through infected vectors and by aerosol was met on the ground by a well-organized public health mobilization of prophylaxis and vector annihilation. Ultimately, the defense prevailed. 37

The ISC Report’s availability – at long last – in electronic format will greatly impact Cold War scholarship and the absurd continuing hostilities between the US and North Korea. The most controversial content of the entire Report at the time of its release was the interviews conducted with the four US POWs which included three Air Force pilots, Lt. Paul R. Kniss, Lt. Floyd B. O’Neal, and Lt. John Quinn and one navigator, Lt. Kenneth L. Enoch. These airmen had previously written confession statements which were broadcast internationally by Chinese radio. The ISC interviews clarified details of the Air Force indoctrination procedures to prepare the airmen to drop germ warfare payloads. In the US, the airmen had been given “cautious informatory lectures” and had not been apprised of what they were expected to do. Later, at overseas American and Japanese bases they were briefed that “bacteriological warfare was said to be theoretical and purely defensive.” Then they were briefed that the Chinese and North Koreans had these weapons and the US had to be prepared to retaliate in kind. When the airmen arrived in Korea, the “pilots were surprised to discover it had already been started.” 38

The confessions of Quinn, O’Neal, Kniss, and Enoch are representative of all the American POW confessions regarding BW deployments. The pilots expressed great remorse for their actions which they understood as war crime violations of international law, and asked forgiveness. The confessions contained abundant knowledge about the diseases and vectors to be dispersed, the altitudes and wind directions for optimum deployment, the payload terminology for pre-flight briefings and return debriefings, the names of briefing officers and instructors with dates and locations of these sessions, remarkable details regard bomb mechanisms and mechanics, including hand-drawn diagrams of bombs with cut-away internal workings and release mechanisms all neatly labeled, and extensive narratives of base activity, pre-flight logistics, munitions loading, and general discussions.

The information divulged in these confessions was far too detailed, and too much in agreement to have been made up. Similarly, individual confessions were far too divergent in length and narrative style to be dictation. What is revealed is that, as a group, these young men in their late twenties and early thirties were all highly intelligent “A” students who knew how to take meticulous class notes, retain lecture information, study and pass tests in order to advance their promotion to pilot and navigator training in the rigorous and competitive Air Force education system. These pilot confessions are true, remorseful, soul-searching efforts of expiation. Reading them today with the passage of time leaves no doubt.

However, the confessions were immediately denounced by US Army psychologists as evidence of an insidious new method of communist Chinese brainwashing which could plant false memories in the pilot’s psyche. Evidence for this argument centered on the inclusion of communist slogans in the confessions such as “imperialist warmongers.” Obviously, there had been political debriefing in the POW camps. Nevertheless, the officers readily confessed without being tortured by their guards. 39 Captured British soldiers gave up no information beyond name, rank and serial number, but the US airmen voluntarily spilled their guts, so the question remains, why?

The explanation that emerges from the confessions is that the airmen felt extreme resentment towards the Air Force for deceiving them into committing morally repugnant acts. They were from good families, raised as Christians, then ordered to fly missions dropping germ bombs, which felt sinful. They had been misled into this dirty work which they had to obey or face court-martial for refusal. Furthermore, their BW payloads were loaded onto their planes not by fellow Air Force personnel, but by strangers (CIA personnel) who treated them as subordinates and ordered them not to inspect the payloads. The airmen's confessions reveal this deep undercurrent of guilt and anger.

Following repatriation after the ceasefire, the airmen faced intense debriefing. They were given the ultimatum to recant their confessions or face a vindictive court-martial. Falsely confessing to a war crime could result in a twenty-year sentence, and these were young men with their whole life ahead of them. If they accepted the Army psychologists’ explanation that they had been brainwashed, they could then disavow their confessions, sign affidavits agreeing to forever keep the secret, exit the military with an honorable discharge, and receive the benefits of the new GI Bill. The Army psychiatrists also let them in on another little secret — the BW campaign had been a failure, they had not really committed the horrible moral sins for which they were beating themselves up. They could sleep in peace, get on with their lives, and they all accepted.

The US government’s charge of communist brainwashing has its own covert history. Projection blaming, as the psychological term implies, means accusing another of one’s own actions. It is well studied in psychology, for frequently in family relationships both the blamer and the blamed are unaware of the real situation. But when projection blaming is done tactically by a government, it frequently masks race warfare and class warfare. The US charge of communist Chinese brainwashing served to mask two top-secret CIA covert research projects involving brainwashing. The first under the code name Artichoke utilized psychotropic drugs such as LSD to conduct secret mind-control experiments on American citizens. The second project in collaboration with ex-Nazi war criminals under the codename MKUltra developed special interrogation techniques at black sites in Germany where suspected Soviet agents were tortured and murdered. This history of institutionalized criminal behavior within the CIA is rapidly coming into the sunshine. 40

The charge of brainwashing leveled against the Chinese also shows how deeply embedded racism is in US foreign policy. Asians in American culture have long been portrayed as insidious, invidious, and inscrutable— the yellow peril, the red menace, the Mongol hordes. 41 The shifty, nefarious brainwashing of POWs and the theatrical perpetrating of a grand biological warfare hoax by Mao, Zhou Enlai, and Stalin is exactly what Americans should expect from this enemy. Hoaxes and flimflam are deeply rooted in racial prejudice, 42 and the degree to which Milton Leitenberg’s hoax thesis has been accepted in mainstream academia is due in large part to negative racial stereotypes entrenched in the white American subconscious.

Milton Leitenberg’s BW hoax thesis is bunk. It is a house of cards built on forged documents, innuendo, and false facts. 43 The Cold War denial lobby which includes The Woodrow Wilson Center played an important part in promoting this false hoax thesis. There remain powerful political forces in the Joint Chiefs of Staff, Congress, State Department, Defense Department and CIA who do not want this history of US war criminality made public knowledge. It is not beyond the means of this interest group to create false narratives with fraudulent documents and cooperating academics to perpetrate this heinous cover-up. It is long past due for America’s Korean War atrocities to see the sunshine. BW is only one Korean War crime. There is also the violent and routine killing of more than 3000 CVA and KPA prisoners at Koje Island Prison Camp which needs new investigation. The US Army’s strategy of carpet bombing, which destroyed the entire built infrastructure of North Korea, must be addressed in any future reparations and peace talks. Well-intentioned philanthropies such as the MacArthur foundation would be well-advised to reconsider their support for fake research from the CWIHP.

The communist government of China has also played a role in perpetrating Leitenberg’s hoax claim by remaining silent and not vigorously refuting his false narrative. There is no political will at the center of power to push for truth on the BW charge as long as business with the US is booming. The article attributed to Wu Zhili remains available online to blink brightly as the shiny lapel pin of China’s “new liberalism.” Chinese historians know better than to revisit this topic. A last footnote regards the long-term impact of the insect annihilation. Western scholars have argued that the mass campaigns of public hygiene through vector extermination caused the destruction of important pollinator species. Along with poor central planning, pollinator destruction led to extremely low crop yields and the post-war famines. The mindset of human domination over nature which began with the insect annihilations lingers in China’s current environmental crisis.

1 Stephen Endicott and Edward Hagerman lay out the most convincing case for US bio-warfare in the Korean War in, The United States and Biological Warfare: Secrets from the Early Cold War and Korea , Indiana University Press, Bloomington, 1989.

2 This recent article contains eye-witness testimony of BW deployment in North Korea in 1952. Julian Ryall, “Did the US use germ warfare in Korea,” The Telegraph , 10 June 2016, www.telegraph.co.uk/news/worldnews/asia/northkorea/7811949Did-the-US-wage-germ-warfare-in-Korea.html

3 “It was all very fishy. They were surprised and unhappy to see us. It was obvious that something suspicious was going on, and that it was a clandestine affair.” From an eye-witness account by a British soldier of an American Army special detachment dressed in “parkas” spreading chicken feathers into private homes in a North Korean village behind retreating UN Forces. The narrative is quoted at length in Peter Williams and David Wallace,  Unit 731: The Japanese Army ’ s Secret of Secrets , Hodder & Stoughton, London, 1989, 265–266.

4 John W. Powell, an American journalist living in Shanghai who published the news magazine, China Monthly Review , was indicted along with his wife, Sylvia Powell and their colleague, Julian Schuman on charges of Sedition for their coverage of the BW allegations during the war. For a concise history of the Powell-Schuman Sedition Trial, see Stanley Kutler,  The American Inquisition: Justice and Injustice in the Cold War , Hill & Wang, New York, 1982.

5 A Bruise — Terror of the 731 Corps , a film by Haruko Yoshinaga, broadcast November 1976, Tokyo Broadcasting System. Yoshinaga succeeded in locating and interviewing twenty former members of Unit 731.

6 John W. Powell, “Japan’s Germ Warfare; The US Cover-up of a War Crime,”  Bulletin of Concerned Asian Scholars , Vol. 12, No.4, Oct–Dec 1980, 10.

7 On the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons , Foreign Languages Publishing House, Moscow, 1950

8 Williams and Wallace, Unit 731 , 263

9 Ibid., 260

10 “Anthrax infection by the respiratory route is significant with the work of bacteriological warfare carried out in the United States. Research from Camp Detrick published in 1946 and 1947 (see App. AA & II) show that it has been possible to obtain new strains of anthrax bacilli cultured in synthetic media which not only possess unusually high virulence, but are especially adapted to the respiratory route of infection.” Report of the International Scientific Commission for the Investigation of the Facts Concern Bacterial Warfare in Korea and China ( ISC Report ) , Peking, 1952, 34

11 Chinese Medical Journal, Sept.–Dec. 1952, 335–660.

12 Endicott and Hagerman give an interesting account of the pilot’s recantations of their confessions in The United States and Biological Warfare , 166-170.

13 Eric Olson has worked tirelessly to shed light on his father’s murder. Here is a summary of the Frank Olson murder case with sources: [ www.serendipity.li/CIA/olson2.htm ] The Netflix six-part documentary, Wormwood , directed by Errol Morris, investigates the Olson assassination and the shadowy CIA operations which surrounded it.

14 ISC Report , 1-62

15 Thomas Powell, “Korean War Biological Warfare Update,” Socialism and Democracy , Vol. 31, No. 3, 2017, 133. This does not mean that the Army, the Air Force and the JCS were not operational in germ war deployment, but the CIA provided the covert oversight to bury the evidence.

16 Kathryn Weathersby, “Deceiving the Deceivers: Moscow, Beijing, Pyongyang and the Allegations of Bacteriological Weapons Use in Korea,” Cold War International History Project Bulletin 11, 176-180; Milton Leitenberg, “New Russian Evidence on the Korean War Biological Warfare Allegations: Background and Analysis,” Cold War International History Project Bulletin 11 (Winter 1998), 180-199.

17 Milton Leitenberg, “China’s False Allegations of the Use of Biological Weapons by the United States during the Korean War,” Cold War International History Project , Working Paper #78, Woodrow Wilson International Center for Scholars, Washington DC, 2016.

18 Powell, “Korean War Biological Warfare Update” (n. 15), 121-137.

19 According to Leitenberg’s 1998 narrative, Yasuo Naito, then a Moscow-based correspondent for the Japanese newspaper Sankei Shinbun, claimed to have received a hand written copy (presumably in Russian) of the dossier from an unknown person apparently with access to the Kremlin’s restricted Presidential Archives. Excerpts of the document cache were translated into Japanese by either Mr. Naito or his employer and published in Sankei Shinbun. Leitenberg further claims that Naito provided him with a typed copy of the hand written copy (also presumably in Russian) which was subsequently translated into English by Kathryn Weathersby.

20 I am grateful to Jeff Brown and Godfree Roberts for locating complete volumes in Chinese and English of the 669-page ISC Report , PDF: http://tbf.me/a/quZgG : Complete ISC Report divided into chapters and appendices, PDF: https://www.transferbigfiles.com/7c74a903-6835-4e0d-acc4-bc4d22c77f63/kIVMrNLhwCoTprftiPre-w2 /fulltext

21 AP dispatch 5/19/57

22 Bruce Cumings makes this argument in The Korean War: A History , Modern Library Chronicles Book, New York, 2010, see Chs. 1 and 6.

23 Judith Shapiro makes this argument in Mao’s War Against Nature: Politics and Environment in Post-Revolutionary China , Cambridge University Press, Cambridge, 2001

24 Nikolai Nikolayevich Zhukov-Verezhnikov: Born July 12, 1908 in Moscow, died February 26, 1981. In the 1930s graduated from the Medical Faculty of Moscow University. From 1932 to 1936 and from 1941 to 1947, worked in the Saratov Research Institute of Microbiology. In 1947 he organized and headed the Laboratory of Experimental Immunobiology at the Institute of Experimental Biology of the Academy Medical Sciences of the USSR, Director of Institute 1948-1950. Elected full member of the USSR Academy of Medical Sciences; from 1950 to 1953 was Vice-President of this Academy. From 1953 to 1954 he was First Deputy Minister of Health of the USSR. His c.v. continues for several more pages.

25 The Khabarovsk Trials were held specifically because the US shielded Ishii and his BW collaborators at the Tokyo War Crimes Trial. The US denied Soviet prosecutors the opportunity to interrogate Ishii, claiming that no Russian soldiers or civilians had been victims of BW crimes and therefore the Soviets lacked legal standing. The Soviets and the Chinese were adamant that Unit 731 and Unit 100 BW war crimes were prosecuted and part of the historical record of the war.

26 The denunciation of Zhukov as a KGB agent and provider of false evidence needs to be sourced to specific evidentiary documents, or it should be retracted.

27 Accessible at CWIHP, http://digitalarchive.wilsoncenter.org/document/123153

28 Accessible at CWIHP, http://digitalarchive.wilsoncenter.org/document/123154 , an amended version was published in The Korea Society Quarterly 3 (Fall 2000): 10-11, 44-45. The workshop was organized by Kathryn Weathersby, the translator of the Russian dossier, and Christian Ostermann, Director of the Woodrow Wilson Center.

29 At the June 2000 CWIHP workshop Méray stated, “I fled to the West after the 1956 Revolution. The Voice of America radio station sought me out virtually in the first moment, while I was still in Vienna. They asked me to issue a statement saying that the germ warfare was a lie. I replied that I could not say that I did not see what I saw. The most I could do was to have doubts about the explanations of what I saw.” CWIHP digital Archive #3, p.4.

30 The Wu Zhili author states, “My personal analysis was: (1) Imperialism is capable of carrying out all manner of evils, and bacteriological war is not an exception. (2) Severe winter, however, is not a good season for conducting bacteriological war. When the weather is cold the mobility of insects is weakened, and is not conducive to bacteria reproduction. (3) Dropping [objects] on the front line trenches, where there are few people and sickness does not spread easily, and where the U.S. military’s trenches are not more than ten meters away, allows for the possibility of ricocheting. (4) Korea already had an epidemic of lice-borne contagious diseases. All the houses in the cities and towns had been burned down, and the common people all lived in air-raid shelters. Their lives are already difficult, but the Korean people are extremely tenacious and bacteriological warfare cannot be the greater disaster that forces them to surrender. (5) Our preliminary investigation still could not prove that the U.S. military carried out bacteriological warfare.” Quoted from Milton Leitenberg CWIHP Working Paper #78, March 2016, addendum Document #19

31 Yanhuang Chunqiu , founded in 1991 by retired general Xiao Ke, is considered a dissident or liberal reformist monthly journal in the People's Republic of China. It promotes the view that Enlightenment humanist interpretations of history should be considered in conjunction with Marxist class warfare interpretations of history. The website of the magazine was temporarily taken down by the site administrator ten months prior to the publication of the Wu Zhili memoir for failure to submit the required annual paperwork. The article remains archived for download.

32 ISC Report , Appendix AA, 361-71

33 ISC Report , Appendix FF, 449-69, A total number of infected individuals and fatalities in the region is not given, but to arrive at the 73% mortality rate, a prime number, would indicate that the outbreak was substantial.

34 Wu Zhili, Summary of Health Service in the War to Resist US Aggression and Aid Korea , People’s Medical Publishing House, Beijing, 1988, 15 (trans. Yi Huang and Thomas Powell).

35 For example, Leitenberg’s character Wu Zhili states, “Later, in 1987, a few army leader cadres ran into me and said, ‘The American imperialists engaged in such massive germ warfare but our side didn’t even have one death!’ By then, I thought this was unimaginable.” Leitenberg, “China’s False Allegations” (n. 17), Doc #19, 70. As with the melodramatic fear of beheading, this theatrical vignette strains credulity.

36 Cuba has a long experience of bio-terrorist attacks from the United States which include swine flu, sugar cane rust, and blue mold. In 1981, a US caused epidemic of hemorrhagic dengue broke out in Cuba infecting more than 300,000 people and killing 158, of which 100 were children. Cuba is fortunate to have invested in its public health system which has been able to react promptly to identify and contain outbreaks. The US’s ongoing BW assault against Cuba has been well documented. Ariel Alonso Pérez, Biological Warfare Against Cuba , Capitán San Luis Publishing House, Havana, 2008

37 The Japanese BW experiments in Manchuria of Unit 731were much more successful in mass killings of civilians because there was no functioning government to organize public health responses. Ishii was able to sell a glowing picture of BW military capability to both his superiors in Japan and later to his American handlers.

38 The order to begin the BW attacks was given in November 1951 during the period of the Kaesong peace talks.

39 The treatment of American and all UN POWs in Chinese and North Korean prisons by the communists was humane. There is no evidence of any physical mistreatment or starvation rations. This sharply contrasts to the treatment of PVA and KPA prisoners in the US-run Koje Island prison camps where internees were daily brutalized, beaten, kept on starvation rations, forcibly tattooed with anti-communist slogans by Kuomintang Army guards, and more than 3000 POWs were shot or hanged for resistance or on various other pretexts. This unknown war crime by the US Army is another reason the Korean War has been forgotten. For a full account of this atrocity, see Wilfred Burchett and Alan Winnington, Koje Unscreened , Britain-China Friendship Association, London, 1952

40 For a recent report see: George Burchett, “Wormwood and a Shocking Secret of War: How Errol Morris Vindicated my Father, Wilfred Burchett,” Counterpunch.org , 12 January 2018.

41 “The air war was ineffective and the US was losing many planes to Soviet MIGs. But neither side could acknowledge that. The North Koreans and Chinese armies were dug deep underground and not vulnerable to air strikes. Mostly civilians and civilian infrastructure were the victims of bombardments and it was bad PR for US (UN). . . .Dropping germs into caves, underground shelters and other facilities with a high concentration of troops etc. would have been a very logical move. The US had the means, the motive and willingness. . . .To Yanks & Allies, the 'gooks' were vermin. So why not exterminated them like vermin using vermin, bugs, flees, spiders, clams, anthrax. . . .” Private correspondence to the author from George Burchett, 1/28/2018

42 .” . . the Vale dwellers, that superior, lighter race—perhaps because they make clear that race and racialism have plenty to do with the hoax and its success.” Kevin Young, Bunk: The Rise of Hoaxes, Humbug, Plagiarists, Phonies, Post Facts, and Fake News , Greywolf Press, Minneapolis, 2017, 18. Young describes hoax after hoax that embody racial stereotypes. While criminal scams and fraud are universal, Young argues that there is something particularly American about hoaxes as theatrical entertainment. The “tall tale” he claims is a uniquely American literary genre.

43 For example, Leitenberg writes, “During World War II, the US BW program was engaged solely in research, and it had produced no stockpile of BW agents. After 1945, the United States neither produced nor procured any biological munitions until the end of 1951.” Leitenberg, “China’s False Allegations” (note 17), 8. This serious claim is directly refuted. “An offensive [US] biological program began in 1942 under the direction of a civilian agency, the War Reserve Service (WRS). The program included a research development facility at Camp Detrick, Maryland, testing sites in Mississippi and Utah, and a production facility in Terre Haute, Indiana. Experiments were conducted using pathogens including B. anthracis  and  Brucella suis .” George W. Christopher, et. al., “Biological Warfare: A Historical Perspective,” in Joshua Lederberg, ed.,  Biological Weapons: Limiting the Threat , MIT Press, Cambridge, MA, 1999, 22. Furthermore, the US acquired Unit 731 research in 1947, plenty of time to have operable BW weapons by 1951.

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• The British, the Indians, and smallpox: what actually happened at Fort Pitt in 1763? Ranlet P. Ranlet P. Pa Hist. 2000;67(3):427-41. Pa Hist. 2000. PMID: 17216901 No abstract available.
• Military medicine and the ethics of war: British colonial warfare during the Seven Years War (1756-63). Charters E. Charters E. Can Bull Med Hist. 2010;27(2):273-98. doi: 10.3138/cbmh.27.2.273. Can Bull Med Hist. 2010. PMID: 21465842
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Biological Warfare Thesis

How to write biological warfare thesis.

Biological warfare means using biological agents like bacteria, viruses, toxins, etc. as biological weapons against the war enemy. The main intention of such is to cause casualties by the medium of air, water, cattle, or crops. The instances of the use of biological weapon can be found as early as in the ancient world like in Trojan War, or the sacred war of Greece. And the recent instance is the infamous use of Anthrax post September 11 attack in New York. Many succumbed to death with anthrax a disease caused by bacteria Bacillus Anthracis, allegedly used as a bio weapon by bio- terrorists. With so many interesting avenues to explore, biological warfare is a popular topic among the students of biology, chemistry, biochemistry, medicine, etc. For an expert assistance for your biological warfare thesis , you can depend on ProfEssays.com .

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Embrace the following ideas for a good biological warfare thesis –

• The mechanism- the easiest way to attack the enemy is by contaminating the water and crops used by a community. Also, the viruses like anthrax are released into air so that those inhaling contract the disease. The main diseases that are the results of biological warfare are anthrax, small- pox, plague and cholera among others.
• The history- the use of biological weapons in war dates back to antiquity. It has been used in many wars including the First and the Second World War. Besides, the terrorists also have used it to infect the people, for instance in 1990s and early 2000s. Thus there are a lot of instances and possibilities of terrorists using bio weapons for their target.
• The consequences- the people will get the disease soon after coming into contact with the evil agents. Also the weapon may stay in the water and air for long time, even decades and centuries thus causing hazard to the victims. The diseases caused can be minor and sometimes deathly.
• The prevention- there are systems that detect biological agents in the environment. Also the defense mechanisms of a country need to be tightened. It is said that biological terrorism is may take place anytime in USA. Thus, USA has already embraced bio- defense mechanism to ensure least damage in case of bio- terrorism. However, it still remains a challenge because there are many agents that can be used as bio- weapons and hence dealing with the same means a lot of effort and expenditure.
• The conventions- Biological Weapons Convention was held in 1972 with as many as 80 countries participating with many amendments later. This restricts the testing, holding and developing of biological agents that can be used for as bio- weapons. In spite of the strict rules and regulations, many countries are alleged to have continued to develop bio- weapons.
• The war- for the essay you can also talk about the various war that have used the bio- weapons. You can talk about how, which biological agents were used, and the extent of impact they created. For instance, you can focus on the use of anthrax by the bio terrorist in USA in 2001, or those used in Second World War.

Decide the topic that interests you and in which you have enough support. Talking to the classmates and the instructors is a good way to gather ideas. And remember that introduction comes first in the essay then comes the body part and finally conclusion. You can borrow further help on this regard from the link useful prompts to help you to write your essay paper. And remember a good essay depends upon the time you spent and effort and interest you put in it.

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