Technological Change and Biological Warfare

Malcolm R. Dando has a doctorate in neurophysiology from the University of St. Andrews, Scotland, and is professor of international security in the Department of Peace Studies at the University of Bradford, UK. Simon M. Whitby is a research assistant for the Bradford Project on Strengthening the Biological and Toxin Weapons Convention [www.brad.ac.uk/acad/sbtwc]. He is currently completing a doctorate on anti-crop biological warfare programmes.

Infectious diseases have caused great suffering and loss of life throughout human history. Biological warfare is the deliberate spreading of disease among humans, animals and plants. There are a number of historical examples which show that biological warfare has been in use since antiquity. Early accounts, dating back to 300 bce, relate to ad hoc attempts to spread disease through the contamination of water supplies. This tactic of warfare, and the use of catapults to propel diseased human cadavers into besieged army fortifications, appear throughout the historical record until as late as 1763.

 

During the latter half of the eighteenth century, biological warfare had become disease-oriented with both the British and the French attempting to introduce smallpox as a form of deliberate infection during conflicts against native American Indians.

 

During the First World War, Germany was accused of spreading cholera in Italy and plague in St Petersburg. There is also evidence that German agents conducted covert anti-animal sabotage, infecting livestock with anthrax and glanders and disrupting American shipments of horses to the theatre of war in Europe. In what can be regarded as an early example of anti-crop biological warfare, grain shipments were also the target of German sabotage operations in the First World War.

 

The late nineteenth and early twentieth centuries saw the scope of biological warfare expand considerably. The “Golden Age” of bacteriology had emerged with scientists such as Pasteur and Koch demonstrating the causal relationship between pathogenic micro-organisms and disease. The potential of deliberate infection as a form of warfare against man, animals and plants had by the early 1920s become the subject of systematic scientific study in several countries, including France, as French records show. During the inter-war years biological warfare research had progressed in Japan to the point where large-scale field-trials were carried out against the Chinese population with weaponised biological agents. But it was not until the Second World War that the frightening potential of biological warfare was fully realised.

 

British research resulted in an anti-animal warfare capability prior to the end of the war and the production of some five million anthrax-impregnated cattle cakes. Related British investigations produced an effective means of disseminating an aerosolised cloud of highly infectious, lung-retention-sized particles from a liquid suspension of deadly anthrax bacteria. The British also experimented with botulinal toxin, and anthrax field trials such as those conducted at Gruinard Island off the coast of Scotland quickly confirmed that biological weapons had much greater potential than any known chemical weapon.

 

Britain, Canada and the United States collaborated on the development of an anthrax bomb during the Second World War, but the project was not completed before hostilities ceased. The US operation, however, was rapidly expanded in the post-war period. Building in part on data supplied by Britain, the United States undertook a comprehensive programme of research and development through to the late 1960s which saw the production and weaponisation of both anti-personnel and anti-crop agents.

 

President Richard Nixon’s announcement in 1969 that the United States was unilaterally renouncing further offensive biological warfare research and development paved the way for the negotiation of the 1972 Biological and Toxin Weapons Convention. The former Soviet Union was a co-depository state of the convention along with Britain and the United States, but under conditions of great secrecy it rapidly expanded biological weapons research and development in a programme that was active until the early 1990s. This clearly utilised the growing knowledge of very dangerous viral agents and the new revolution in biotechnology (i.e., genetic engineering).

 

Contemporary concerns over the proliferation of biological weapons have been heightened by revelations that by the start of the Gulf War in 1991 Iraq had conducted a comprehensive programme of biological warfare research, resulting in the weaponisation and deployment for use of anti-personnel agents including anthrax and botulinum toxin. Recent estimates suggest that Cuba, Iran, Libya, North Korea, Sudan and Syria also either have or are seeking weapons of mass destruction, and that more than twelve states have offensive chemical and/or biological weapons programmes. This, then, brings a particular urgency to the need to reduce the threat posed by biological warfare.

 

The main intention of this paper is to describe the “classical” anti-personnel and anti-plant biological warfare agents. It goes on to consider briefly how the biological war threat might develop in the next century should attempts to strengthen international prohibitions fail.

Pathogens

There are a number of micro-organisms that are responsible for causing disease in humans and crops, but not all have been considered suitable for potential military use. Two well-known diseases in humans are cholera and measles.

 

The causal agent of cholera is the bacterium Vibrio cholera. The bacterium causes a diarrhoeal disease which can be spread among humans from the supply of infected water. Its effects are caused when the bacterium lodges in the intestinal wall. This results in the secretion of a toxin which causes severe diarrhoea and huge loss of fluids. While cholera can be treated by modern methods the spread of the disease in the last century was responsible for a large number of deaths and it remains a threat to populations with inadequate public health provisions.

 

Measles is caused by a virus that only infects human beings. The virus spreads among humans by direct contact and can be carried through the air. While infants acquire passive maternal immunity to the disease for a period of six to nine months following birth, vaccination confers lifelong immunity. Given its characteristics it is likely that measles will remain an endemic disease which causes epidemic outbreaks every few years in an unvaccinated population. Mortality is highest among the very young and very old and can reach 5–10 per cent in poor conditions. At present, measles kills 1.5 million people annually worldwide and infects 50 million.

 

Highly contagious agents were not favoured for development as weapons during the mid-century US biological warfare programme as that would have required an effective means of immunising friendly troops and civilians to minimise the risks associated with the use of such organisms. However, highly contagious agents such as plague and smallpox appear to have been weaponised on a large scale in the late–Cold War programme of the former Soviet Union.

Classical Agents

Agents for military operations include those which can be delivered rapidly and produce a certain effect consistently. They need to be effective in low doses, have a short and predictable incubation period, be easily producible on a large scale and be stable in storage and on dissemination. A number of micro-organisms display the above characteristics, allowing the biological weapons designer to choose, for example, whether to use an incapacitating or a lethal agent, one that is not contagious after first use or one that remains contagious only from the point of dissemination. In order to achieve a significant strategic military effect with an anti-personnel agent, the agent would have to be spread in the air and inhaled through the lungs by the intended victims. Such an attack could be devastating. The US Congress Office of Technology Assessment (OTA) suggested in 1993 that whereas a 1 megaton nuclear weapon might kill up to 1.9 million people if detonated over Washington, D.C., 100 kilograms of anthrax spores in the right conditions could kill as many as 3 million. Similar calculations regarding the potential effectiveness of biological weapons have essentially arrived at the same conclusion and such estimates remain uncontested.

 

Because of the relative openness of American society a good deal is known in general terms about the “classical” agents selected for weaponisation during the offensive US biological weapons programme. Some details about these agents are set out below. Biological warfare agents consist mainly of bacteria, viruses, Rickettsiae (a type of bacterium), some toxins and fungal agents:

Anthrax 

Anthrax is caused by the bacterium Bacillus anthracis. It is a disease that affects herbivorous animals. Infection arises from contaminated material in the field and the bacterium grows quickly in the body of the animal. When the animal dies the bacterium is able to form hardy, environmentally resistant spores which can be reactivated in the body of the next victim. Infection can occur in humans through inhalation of the spores (as in pulmonary anthrax), through breaks or lesions in skin, or by ingestion of contaminated material. Although modern prophylaxis can effectively treat the infection, if intervention is not immediate the disease is almost inevitably fatal. The incubation period is relatively brief and results in death in just a few days in 95 to 100 per cent of all untreated cases. The effectiveness of vaccines against a heavy inhalation dose of anthrax in humans is not known.

 

These characteristics, particularly the environmental resilience and stability of the spores, make anthrax the agent of choice in most known biological weapons programmes. If the agent is dried and milled to between one and five microns in size spores will be retained in the lungs, and if an attack is carried out at night to avoid ultraviolet light degradation of the spores’ viability, it could be extremely effective.

Brucellosis

Brucellosis is a bacterial disease of domestic animals that can also infect humans. Brucella melitensis attacks goats, Brucella aborus attacks cattle, Brucella suis attacks pigs and Brucella canis attacks dogs. Brucella melitensis is the strain that affects humans most severely. Although seldom lethal it can result in long-term incapacitation lasting months. The organism is capable of surviving for long periods in the environment and no vaccine is available for humans.

Q Fever

Q Fever is caused by Coxiella burnetii, an obligate intracellular rickettsial organism. Rickettsiae are similar in form and structure to bacteria, but will only grow inside living cells. Q Fever is a widespread disease of domestic livestock. In humans the infection results in an incapacitating illness. The organism can persist for long periods in the environment and is highly infectious.

Tularemia 

Otherwise known as “rabbit fever”, Tularemia is a bacterial infection caused by Francisella tularensis. Besides rabbits, it also affects rodents, hares and foxes. The organism can infect humans through ingestion of contaminated food or water, or via the lungs. It is a hardy organism, can survive for long periods in the environment and infects at low doses. Modern prophylaxis is available for this agent. The disease causes a severe debilitating illness and kills one-third of all untreated cases. During the US programme, Tularemia was developed to be resistant to some commonly used antibiotics.

VEE Virus

Venezuelan Equine Encephalitis virus is a member of the Alphavirus genus. It can be spread among humans by mosquitoes and arthropod biting vectors such as fleas. The virus has a wide range of natural hosts and produces a fatal disease in horses. In humans the incubation period is between two and five days. The infection results in a seriously debilitating influenza-like illness which lasts for about a week. The virus is very stable in the environment, is highly infectious to humans and can be produced in large quantities by relatively unsophisticated methods.

Toxins

It can be seen from the information above that during the middle years of this century a range of bacterial, rickettsial and viral agents were weaponised by the United States. At that time, more was known about bacteria and rickettsial agents than about viruses. Viruses are not cellular organisms. They consist of genetic material and a protein coat and must invade a living cell and take over its operations in order to reproduce and survive. However, many bacterial organisms produce deadly toxins, and this provided another possible way in which to use biological agents. Toxins are non-living chemicals, so they would be expected to produce a faster effect as weapons because they do not have to reproduce in the body to cause disease. The following two toxin agents were weaponised during the US programme:

Botulinum Toxin

Botulinum Toxin is produced by the bacterium Clostridium botulinum. The bacterium produces seven neurotoxins, all of which are capable of affecting humans. Many deaths in humans result from the food poisoning known as “botulism”. The toxin is considerably more powerful than the most lethal nerve agents and its effects can be induced through inhalation. For serotype A, the estimated lethal dose of the toxin is just 0.001mg/kg of body weight. If the victim is not treated swiftly, death occurs through paralysis of the respiratory muscles. An anti-toxin is available but the victim must be tested for horse serum sensitivity prior to administration.

SEB

Staphylococcal Enterotoxin B is one of the exotoxins produced by the bacterium Staphylococcus aureus. As the toxins exert their effects upon the victim’s gastro-intestinal tract they are, somewhat confusingly, called enterotoxins. The toxin is frequently the cause of food poisoning by contaminated food. It is toxic at very low doses and can be used as a biological weapon through inhalation. It is classed as an incapacitating agent. It works on humans through a complex interaction with the victim’s immune system which leads to an overproduction of cytokines (biologically active peptides). Reaction to inhalation of the toxin sets in within hours and the victim experiences an acutely debilitating illness involving fever, vomiting, diarrhoea and headaches which lasts for several days. However, the illness is rarely fatal and with appropriate care the victim should recover fully in a few weeks.

Agriculture

It will be noted that thus far the discussion has excluded biological warfare against animals. The United States never developed weapons specifically to target animals, but work on anti-crop agents did result in an offensive military capability. There is increasing concern in the United States over the vulnerability of agricultural production to diseases that could potentially have serious effects upon livestock and the production of food and cash crops. Approximately 860,000 US workers (16.9 per cent of the workforce) are involved in agricultural production, which constitutes approximately 13.1 per cent of America’s gross domestic product. Agricultural exports alone amount to some $140 billion. Domestic agricultural production is heavily concentrated and livestock production is of considerable economic importance.

Animal Pathogens

A number of animal diseases pose a particular risk to the US livestock industry. Two such diseases are foot-and-mouth disease and African swine fever. Foot-and-mouth disease is caused by a highly infectious virus. It can be spread via meat products and the movement of infected animals. It is known to have been spread in aerosolised form and carried great distances by wind. The virus results in a chronic disease which forms blistering on the tongues, lips and feet of livestock. Some strains of the disease can cause up to 30 per cent mortality. Between 1946 and 1952 the United States spent approximately £200 million on an eradication campaign in Mexico to prevent the disease spreading.

 

African swine fever is caused by a virus which overwhelms the immune system of pigs. The disease can be spread via the movement of contaminated animals and by arthropod vectors such as tics. Pig breeding in the United States is so concentrated that nine northern and eastern states produce approximately 74 per cent of American swine.

Plant Pathogens

Biological warfare against crops could have potentially devastating consequences. Humans are heavily dependent upon the production of staple food crops such as potatoes, rice and wheat. Some crops, such as tea, coffee, rubber and tobacco, are of major economic significance. Plant pathogens have caused crop epidemics worldwide resulting in economic losses running to billions of dollars. They have also caused famines. A pathogen causing coffee-leaf rust destroyed commercial coffee production in South-East Asia, and in the nineteenth century a pathogen causing leaf blight in rubber plants prevented the development of a viable rubber industry in South America. In 1845–6 a pathogen affecting potatoes was a major cause of the Irish famine, which killed a million people. And a pathogen causing brown spot disease in rice was a cause of the devastating Bengal famine of 1943, in which more than two million people died.

 

In the United States, military interest centred on naturally occurring fungal plant pathogens as potential anti-crop weapons. Fungi reproduce by means of microscopic spores, millions of which in nature are scattered among susceptible plants by wind. Many such spores are hardy and resistant to environmental and climatic conditions and such pathogens lend themselves well to weaponisation.

 

Although there is no evidence to suggest that such pathogens were ever used during hostilities, the US programme standardised and stockpiled two principal anti-crop agents in large quantities. Puccinia graminis tritici is the causative agent of black stem rust in wheat. A fungus, it has caused epidemics responsible for severe losses in the crop. The related Puccinia species cause epidemics in other cereal crops such as oats and rye. The chief characteristic of this pathogen is its ability to reproduce rapidly once the disease has become established on host plants. The natural disseminating form of this pathogen is a microscopic spore. According to one estimate a moderate infection of black rust fungus will reproduce at 4 x 2024 spores/day/hectare. Spores have been shown to infect crops after travelling distances by wind in excess of 3,000 kilometres.

 

Piricularia oryzae, a fungal plant pathogen, is the causal agent of rice blast disease. The fungus reproduces by means of minute spores known as conidia. Once settled on a rice plant the spores invade the host and reproduce rapidly. For germination to take place high temperatures (30°C) and high levels of relative humidity (90 per cent) are required. In nature, the disease is spread by wind dissemination of the spores. Some 80 million microscopic spores have been found on as little as one square centimetre of infected rice leaf. There are instances of crop losses in which as much as 90 per cent of production has been destroyed by this pathogen.

Lethal Doses

The production of militarily significant quantities of anti-personnel and anti-crop agents is such that a would-be proliferator runs the risk of detection. One estimate suggests the amount of anthrax required for a night attack against unprotected civilians: if ID50 is the dose required to infect 50 per cent of an exposed population, a single attack would require 1012 ID50 or one trillion doses. The simplest method for a proliferator would be to attempt to grow the required amount of bacteria by a process of fermentation. Assuming that a concentration of 108 bacterial cells/ml could be reached in the fermentors, and that the agent was anthrax which has an estimated ID50 of approximately 104, the proliferator would need to grow: 1012 x 104/108 x 1,000 = 100,000 litres of bacterial suspension.

 

Production of the above bacterial suspension would require ten 100-litre-capacity fermentors, each needing ten production runs. A significant amount of related ancillary equipment would also be required for producing such agents in bulk. Further equipment would be needed to dry and mill the suspension in preparation for weaponisation. There would have to be testing and stringent safety measures, and troops would have to be equipped and trained in deploying such agents and munitions. Such activities would become increasingly difficult to conceal from other countries.

 

The production of sufficient quantities of anti-crop weapons would demand similar facilities and testing. US estimates from the mid-1950s of the amount of agent required per acre of rice crop were as little as two grams. However, the number of aircraft sorties needed for dissemination is thought to be significant, similar to that required to disseminate chemical anti-crop agents. For example, it was envisaged that in order to attack an area of some 2,086 square miles with a chemical anti-crop agent some four hundred aircraft sorties would be required. Such large-scale operations and the sudden and unusual nature of the resulting crop epidemics would be easily detectable.

 

 

FUTURES

 

Biological Terrorism

In the last decade the threat of possible terrorist use of a biological agent has received increasing attention. Indeed, it is reported that besides developing chemical agents, such as those released during the Tokyo subway attacks in 1995, the Japanese Aum Shinrikyo religious cult also researched the possible use of biological weapons, resulting in an unsuccessful attempt to spread one such agent in a Tokyo suburb. It would, of course, also be possible to attempt an assassination with a potent toxin, or to attack people indirectly via the contamination of food or water supplies. However, it is only in the last few months that the potential terrorist threat to the production of livestock and crops has begun to be taken seriously.

Biotechnology

The impact on biological warfare of developments in the field of biotechnology raised concerns among states even during the early 1980s. It was noted during the Second Five-Yearly Review Conference of the Biological and Toxin Weapons Convention in 1986 that modern techniques, including genetic engineering, might greatly facilitate the production of large quantities of bacteria, viruses and particularly toxins.

 

The major proliferation concern of the international community at present remains the threat posed by “classical” biological warfare agents such as anthrax and plant pathogens responsible for major crop losses. However, from what is known about biological weapons programmes in the former Soviet Union, it is clear that research with very dangerous viral agents had advanced to a much greater degree than was possible for the mid-century US programme given the state of knowledge at the time. The Soviet programme had also begun to apply genetic engineering methods—for example, to increase the range of antibiotic resistance of the Yersinia pestis organism, which is the causal agent of plague.

 

Distinct epochs can be identified in the history of biological warfare, with each generation of programmes defined by the application of increasingly sophisticated scientific knowledge. If the first generation of scientific biological weapons programmes arose during the First World War, then those of the Second World War belong to a second generation. If the programme of the former Soviet Union constitutes a third generation in the development of modern biological warfare, the question arises as to what the characteristics might be of a fourth generation as the revolution in biotechnology develops and spreads around the world over the next few years.

 

According to the US Department of Defence we might expect to see future biological warfare programmes in which benign micro-organisms have been genetically altered to produce toxic effects; to increase their resistance to antibiotics; to exhibit greater aerosol and environmental stability; and to overcome the immune system. With regard to anti-plant pathogens, it is clear that our staple food crops are being more and more intensively studied at the genome level, resulting in a deeper understanding of the vulnerabilities of plants to these agents.

Genetic Weapons?

As the revolutions in biotechnology and molecular medicine develop, a wide variety of other ways of misusing scientific knowledge will become available to the weapons designer. One possibility is that so-called genetic weapons could emerge. Such weapons would threaten human groups with specific genetic characteristics in common.

 

The possibility of genetic weapons was raised in a report which appeared in an appendix to the Yearbook of the Stockholm International Peace Research Institute (Sipri) in 1993. The report focuses on potential developments relating to the Human Genome Project, an international effort to map the location and sequence of all human genes. Recent reports suggest that the project may be completed by 2005. Welcome biomedical advances may result from the project, but the possibility that such knowledge could be used for malign purposes cannot be ruled out.

 

For example, the Human Genome Project could produce a clearer understanding of genetic differences between various ethnic groups. The Sipri report notes the possible consequences:

 

Genetic differences may in many cases be sufficiently large and stable so as possibly to be exploited by using naturally occurring, selective agents or by genetically engineering organisms and toxins with selectivity for an intended genetic marker.

 

Sipri’s misgivings were seconded by a British Medical Association report, Biotechnology, Weapons and Humanity, released in January this year. The BMA warned of “weapons which may become a major threat to the existence of Homo sapiens, and a development of biotechnology which perverts the humanitarian nature of biomedical science”. It said weapons that could distinguish between ethnic groups by exploiting tiny genetic differences between them could become a reality within a decade. “In genetic terms there are more similarities between different people and peoples than there are differences,” the BMA said. “But the differences exist, and may singly, or in combination, distinguish the members of one social group from another.” These markers could serve as triggers so that anthrax or plague weapons, for example, could be tailored to ensure the virus would only become active when it identified a certain group of genes characteristic of a specific ethnic group.

 

Genetic weapons are today just a theoretical possibility. But it would be a mistake to assume that such weapons will never emerge. Indeed, the apartheid regime in South Africa was reported to have carried out research on developing biological weapons that would target the country’s black population.

Public Awareness

It is well known that the relevant medical and biological communities and the media and general public worldwide are largely ignorant of the dangers of biological weapons proliferation. Neither are they aware of the importance of the 1972 convention to efforts to prevent the deliberate use of disease as a tool of war. The major problem is that the convention was negotiated during the Cold War and lacks any effective verification measures. Negotiations under way since the early 1990s seek to add an effective verification protocol to the convention. In this connection action is required. The first requirement is that the misuse of biological and medical knowledge in weapons programmes this century become common knowledge in the relevant scientific communities today. Then care must be taken to monitor and publicise developments that give cause for concern. Professional organisations share a responsibility to address these issues, as do individual scientists and journalists. Although a change in the stance of the general public alone will not suffice to prevent the misuse of biomedical technologies, such measures represent necessary elements in humanity’s overall strategy. Scientific advances have long been used to refine weapons of war. Unless the process is resisted, the current revolution in biotechnology could suffer the same fate, producing a new, more terrible generation of biological weapons in the coming century.