Most people think of biological and chemical warfare as similar types of warfare. They are usually thought of as more revolting and unacceptable than any other form of warfare, except perhaps nuclear war. Biological warfare is generally considered to be more odious than chemical warfare.
As we have seen, allegations of the use of chemical weapons in modern times abound but the evidence for the vast majority of them is slim indeed. In fact, there have been very few militarily significant uses of chemical warfare. And this applies even more to modern biological weapons. Although there have been many allegations of their use, not one has been convincingly proved. The strongest evidence by far relates to some use of biological weapons by the Japanese in the early 1940s during their war against China.
But we must conclude that so far there has been no militarily significant use of modern biological weapons in armed conflict. This must not be taken to mean that biological weapons are of no importance. On the contrary. The potential use of modern biological weapons as effective weapons of mass destruction gives them considerable significance in international affairs, a significance that may well be enhanced by developments in genetic engineering.
Activities that can be considered to be forms of biological warfare have, however, a long history. These mainly involve the use of pathogens for sabotage. Perhaps the oldest form of biological warfare was the contamination of wells and reservoirs of drinking water with human and animal corpses. People often had no other choice but to drink the water and many became diseased, particularly if the corpses in the well were infected.
Robinson mentions examples of this tactic from early Persian, Greek and Roman literature and down to 'innumerable European wars, the
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American Civil War, the South African Boer Wars' (Robinson 1971). Infected corpses were also catapulted into cities under siege. In the fourteenth century, for example, plague was introduced in this way into cities under siege. According to Robinson, this technique was used until 1710 when the Russians besieged Swedish troops during the battle of Reval and caused a plague epidemic by throwing bodies infected with plague over the city walls.
In 1763 the British spread smallpox during wars against the native Indians of North America, using contaminated blankets. The British got a taste of their own medicine when the Americans used smallpox against them during the Revolutionary War.
A modern example of such use of biological agents occurred in Brazil where landowners were brought to trial for deliberately spreading smallpox and other diseases among Indian tribes in the Mato Grosso between 1957 and 1963. The landowners wanted the Indians removed from rubber-producing areas.
Unlike chemical weapons, biological weapons were riot used in battle during the First World War. There is some suggestion that the Germans attempted to infect horses with glanders and cattle with anthrax. The evidence for the former is somewhat stronger than that for the latter, but is not convincing.
It is widely believed that biological weapons were used by the Japanese army during the Second World War: as sabotage weapons against the Soviet Union and Mongolia during 1939-40; in air attacks against Chinese cities between 1940 and 1944; and against Chinese troops in 1942 (Robinson 1971). There are reports of plague bacilli being dropped by Japanese aircraft in raids on several Chinese cities. In some cases, the Japanese were reported to have spread plague bacteria by human fleas (Pulex irritans). In 1949 a Soviet military court at Khaborovsk tried twelve Japanese soldiers, including the commander of the Kwantung army, for using biological weapons against Chinese troops and civilians and for using prisoners of war as subjects in biological-warfare experiments.
The Japanese undoubtedly had a large research and development programme in biological warfare, run by a unit of the Kwantung army called Department 731. Directed by General Shiro Ishii, mainly from a base at Pingfan, South Manchuria, it employed over 3,000 scientists, technicians and military personnel. Several thousand others worked in eighteen outstations scattered throughout Japanese-controlled territory.
Japanese scientists investigated several diseases as potential biologi-cal-warfare agents, including anthrax, brucellosis, glanders, tuberculosis and typhoid. During their research they deliberately infected thousands of prisoners of war, mainly Chinese and Soviet, a large
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fraction of whom died in agony. The Japanese biological-warfare research programme was justified by allegations that Soviet spies had used bacteria, particularly anthrax, in sabotage missions into Kwan-tung province in 1935.
A Japanese intelligence report alleges that between 1937 and 1939, during the Japan-China conflict, the Chinese sabotaged water supplies and food supplies on a number of occasions by contaminating them with anthrax and cholera.
Between 1951 and 1953, during the Korean War, the Chinese, Soviet and North Korean communist authorities kept up a continuous stream of accusations that the American military was using biological weapons against targets in North Korea and China, accusations strongly denied by the American government. The human diseases alleged to have been used were anthrax, cholera, encephalitis, meningitis and plague. In addition, American forces were alleged to have spread animal and plant diseases. Diseases were said to have been spread by insects, ticks and small rodents, usually dropped by aircraft.
Boserup et al. analysed in detail the reports of American use in biological agents during the Korean War to illustrate the extremely difficult problem of verifying allegations of use (Boserup et al. 1971). They point out that 'whether the allegations are true or false, they caused the United States a loss of international good-will, even though US requests for impartial investigation were rejected'.
The story is important because it demonstrated the power of allegations of the use of biological weapons to stimulate public opinion. To obtain the propaganda value of such allegations is an obvious motive for making them. This may well explain some of the allegations made since the Korean War. Surprisingly, though, there were no significant allegations of the use of biological weapons by either side during the 1961 - 75 Vietnam War.
A typical example of a probably propagandistic allegation is the accusation made by the Cuban government that America's Central Intelligence Agency used biological agents in Cuba to spread haemor-rhagic dengue and haemorrhagic conjunctivitis in humans and to cause sugar-cane rust, blue mould of tobacco, and African swine fever. The accusations were strenuously denied by the American government. Another example is the accusation in 1970 by the South Korean government that North Korea had caused the epidemic of cholera that struck south-western Korea in 1969.
Biological-warfare agents are disease-carrying substances and organisms. Possible agents include: bacteria, like plague; viruses, such as
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yellow fever; rickettsiae (bacteria-like bodies found in the tissues of lice, ticks, mites and fleas which cause disease, like typhus, when transmitted to humans); and fungi, like coccidioidomycosis. Lethal agents considered suitable for biological warfare include: plague; typhus; smallpox; Rocky Mountain spotted fever; cholera; glanders; Eastern encephalitis; Japanese encephalitis; St Louis encephalitis; Russian spring - summer encephalitis; Argentinian haemorrhagic fever; Bolivian haemorrhagic fever; Crimean - Congo haemorrhagic fever; Korean haemorrhagic fever; Marburg disease; Ebola haemorrhagic fever; yellow fever; anthrax; melioidosis; and tularemia (rabbit fever). Incapacitating biological-warfare agents include: Chikungunya fever; Venezuelan equine encephalomyelitis; brucellosis; Western encephalitis; dengue haemorrhagic fever; Lassa fever; lymphocytic choriomen-ingitis; hepatitis; Rift Valley fever; and Q fever.
The American biological-weapon stockpile which was destroyed, in 1971 and 1972, under the Biological Weapon Convention included at the time of destruction: lethal agents causing anthrax and tularemia; incapacitating agents causing Q fever and Venezuelan equine encephalomyelitis; and anti-plant agents causing rice blast and black stem rust of wheat. In addition, the stockpile earlier contained a lethal agent causing yellow fever and an incapacitating agent causing brucellosis.
Anthrax is the favourite lethal biological-warfare agent. It is relatively very easy to culture in large quantities, easy to disseminate, and, most important, a very hardy pathogen. It can infect both humans and animals, including cows, sheep, horses and pigs.
Anthrax is particularly suitable for dissemination by aerosol because it forms spores which have a protective coating that protects the active material. Not only does this make anthrax bacteria able to survive the rigours of aerosolization, but it also gives them a long lifetime after dissemination. Anthrax spores live for days even in direct sunlight; in soils they can survive for decades, The British tested an anthrax biological weapon on the deserted Gruinard Island in 1942. It was forty years before the island was safe to visit.
Anthrax kills almost all untreated patients. Robinson et al. describe the progress of the disease: 'After inhaling an infective dose of anthrax bacteria, a man is likely to develop symptoms of pulmonary anthrax within 4 days. After a heavy dose, however, the incubation period may be less than a day.' The first symptoms are deceptively mild - usually just a normal cough. But the disease progresses rapidly. 'The victim develops a high fever, vomits; his head and joints ache and his breathing becomes increasingly laboured. He soon collapses and may die within 2 days or less' (Robinson et al. 1973). These symptoms are produced by toxins generated by the growth of bacteria in the patient's body.
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Anthrax, which is not very contagious, is typically hard to diagnose until the terminal phase. This is a major problem because treatment, with antibiotics and immune sera, must be given soon after infection if it is to be effective. Relatively large doses of anthrax are needed to infect humans. 'Something of the order of 20,000 spores are needed to infect a man through his lungs.' Plague is seven times more virulent, and tularemia is a thousand times more virulent than anthrax. But anthrax has the largest death rate in untreated cases, 95 to 100 per cent, compared with 0 to 60 per cent for tularemia and 30 to 100 per cent for plague.
An example of the effectiveness of anthrax is the epidemic which broke out in Sverdlovsk, a city some 1,800 kilometres from Moscow, to the east of the Urals. More than a thousand people were said to have died from exposure to the bacteria.
What caused the outbreak is controversial. The American administration alleged that the research laboratories of a Soviet factory making biological weapons exploded on 3 April 1979. The laboratories were said to be near the hamlet of Kashino, about 30 kilometres from Sverdlovsk, The official Soviet explanation was that the deaths were caused by contaminated meat sold illegally. Anthrax is still common in parts of the former Soviet Union, and the epidemic may have originated in an accident in a vaccine plant.
Tularemia is caused by the bacterium Francisella tularensis, which can be cultured on a large scale. Early symptoms include chills, fever and respiratory difficulties. Chronic effects and debilitation are severe. Some strains, if untreated, have high mortality rates, although other strains are not very lethal.
An example of a typical incapacitating biological-warfare agent is Q (Queensland) fever, caused by the Coxiella burnetti rickettsia. Q fever is not directly transmitted from human to human but is exceptionally infectious (a single inhaled rickettsia may cause infection!). It is rarely fatal.
The rickettsia make good biological-warfare agents because they are easy to grow in tissue culture and can be stored for years without significant loss of viability. They are very hardy in aerosol form and can survive on surfaces for several weeks.
Q fever is similar to severe influenza and can be treated with antibiotics. If untreated, the illness may persist for up to three weeks and patients may be severely debilitated for several weeks afterwards.
The Venezuelan equine encephalomyelitis virus is rarely lethal in humans but very lethal in horses. It is relatively easy to grow. The virus is notorious for the wide range of hosts which harbour it.
Infection causes the sudden onset of influenza-type symptoms, including chills, vomiting, nausea, headache, aching limbs and debili-
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tation. Most patients recover after about a week. The disease is not contagious but can be spread rapidly by mosquitoes. The virus is exceptionally virulent; a single virus may be enough to cause infection.
The anti-plant biological-warfare agent which causes the very destructive disease of rice called rice blast is the fungus pyricularia oryzae. Robinson et al. describe its production: 'It is easy to grow artificially. During growth it produces conidia, the minute seed-like spores through which it propagates itself. These constitute the potential biological-warfare agents. They are easily removed from the culture, and may be stored for long periods' (Robinson et al. 1973). As a biological weapon, the agent could be disseminated as a dust or sprayed as a liquid from aircraft spray tanks.
When a spore lands on a rice plant it will germinate and the fungus will penetrate the plant, eventually infecting all the plant tissue. 'Spore-bearing stalks will later grow out of the tissue to produce new spores that may be detached and scattered by the wind.' In this way, the disease is spread through the crop.
Diseased rice grains do not develop normally. The fungus also causes the stem to break so that grains in the head are lost. Rice blast can cause as much as 90 per cent of the crop to be lost.
Research and development during the Second World War showed that it was possible to produce biological weapons capable of killing populations of people inhabiting a large area, rather than simply for sabotaging water and food supplies. Sabotage weapons normally use vectors, such as fleas or mosquitoes, to spread disease. But the most effective way of disseminating biological-warfare agents for mass killing is in a form suitable for inhalation or absorption through the skin or the eyes.
The most efficient biological weapon, therefore, releases its payload of liquid biological agent as a cloud of very small droplets; in other words, as an aerosol. An aerosol cloud will remain in the air for a significant time. As the cloud travels downwind, the biological agent will fall out of it slowly but steadily, contaminating the area under it.
Aerosol technologies have been well developed for a number of civilian applications, such as the agricultural dispersal of pesticides and paint-spraying. These can be readily modified for military use. Generally, the liquid agent is forced under pressure through a fine nozzle (hydraulic atomization) or the liquid is allowed to flow in a fine stream into a current of gas (air-blast atomization). Hydraulic atomization is used in, for example, bomblets; a small compressed-air cylinder provides the pressure.
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But a simple way of dispersing a liquid biological-warfare agent is an aircraft spray tank. The agent is allowed to flow into, or just below, the slipstream of the aircraft, where it is converted into small drops of a suitable size.
Some biological-warfare agents are best dispersed in less rough ways. This can be achieved in powder form. In a typical bomblet, for example, a small cylinder of compressed air is arranged so that it directs a stream of air along the surface of the powder, blowing it out of the weapon uniformly through an exit slot.
Biological-warfare agents differ from chemical-warfare agents in that the military have never been much interested in biological warfare whereas they are more interested in chemical warfare. Biological agents tend to die quickly, unless in a precisely suitable environment. And their spread is extremely difficult to control. In fact, it is not well understood how epidemics spread. They come and go mysteriously and often die out inexplicably.
Another problem with biological weapons is that they may strike one's own troops as well as those of the enemy. Even if troops are vaccinated, there is always the danger that the disease will ultimately infect friendly civilian populations.
A final argument against the military use of biological agents is that they typically have relatively long incubation periods. Anthrax, for example, has an incubation period of up to four days; tularemia of up to five days; Q fever of up to twenty-one days; and rice blast of up to four days. The military are not keen on weapons that do not act almost immediately.
Although it is easier to mount a biological-warfare attack than to defend against one, protective measures, if adopted efficiently, can be effective enough to reduce considerably the military utility of biological weapons. One problem that the defender has, however, is that it is difficult to detect rapidly a biological-weapon attack; effective detectors that give both a selective and a rapid alarm are not readily available.
The disadvantage is somewhat offset by the delay before the effects of a biological attack show themselves. If an attack is suspected, medical measures can be taken in the incubation period to lessen considerably the severity of the effects of many diseases.
Protective measures include: the use of vaccines and other prophylactic methods of enhancing the body's natural physiological defences against disease; physical protection measures, like the provision of protective clothing, air-filtration and air-conditioned rooms; the destruction of biological agents before they can cause disease by, for
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example, the use of disinfectants; and medical measures to reduce the extent of the infection, particularly the use of antibiotics to treat diseases caused by bacteria and drugs to relieve the symptoms of diseases.
Vaccination is an obvious pre-attack precaution if an attack with biological weapons is feared. So far as the diseases caused by biologi-cal-warfare agents usually regarded as the most likely to be used are concerned, there are several vaccines available for anthrax, and a vaccine is available for each of tularemia, Q fever and Venezuelan equine encephalomyelitis. Vaccines are, however, not available for some potential biological-warfare agents, such as glanders.
Together, protective measures can make biological weapons militarily unattractive to the attacker. It must be emphasized, however, that unprotected populations, not organized to deal with a biological attack, with no, or a few, people trained in protective measures, and having no protective equipment or clothing, may well be decimated by biological weapons.
Large populations are, of course, difficult to protect. Treatment with antibiotics, for example, requires roughly 20 grams of antibiotic per person per dose. The maintenance of sufficient stocks to supply a large population would be an expensive and difficult logistic problem.