Biological warfare

Biological warfare, also known as germ warfare, is the use of any organism (bacteria, virus or other disease-causing organism) or toxin found in nature, as a weapon of war. It is meant to incapacitate or kill an adversary. It may also be defined as the employment of biological agents to produce casualties in man or animals and damage to plants or material; or defense against such employment.

The creation and stockpiling of biological weapons is outlawed by the 1972 Biological Weapons Convention, signed by over 100 countries, because a successful attack could conceivably result in thousands, possibly even millions, of deaths and could cause severe disruptions to societies and economies. Oddly enough, the convention prohibits only creation and storage, but not usage, of these weapons. However, the consensus among military analysts is that, except in the context of bioterrorism, biological warfare is militarily of little use.

The main problem is that a biological warfare attack would take days to implement, and therefore, unlike a nuclear or chemical attack, would not immediately stop an advancing army. As a strategic weapon, biological warfare is again militarily problematic, because unless it is used to poison enemy civilian towns, it is difficult to prevent the attack from spreading, either to allies or to the attacker, and a biological warfare attack invites immediate massive retaliation, usually in the same form.

Biological weapons characteristics

Ideal characteristics of biological weapons are high infectivity, high potency, availability of vaccines, and delivery as an aerosol.

Diseases most likely to be considered for use as biological weapons are contenders because of their lethality (if delivered efficiently), and robustness (making aerosol delivery feasible).

The biological agents used in biological weapons can often be manufactured quickly and easily. The primary difficulty is not the production of the biological agent but delivery in an infective form to a vulnerable target.

For example, anthrax is considered an excellent agent for several reasons. First, it forms hardy spores, perfect for dispersal aerosols. Second, pneumonic (lung) infections of anthrax usually do not cause secondary infections in other people. Thus, the effect of the agent is usually confined to the target. A pneumonic anthrax infection starts with ordinary "cold" symptoms and quickly becomes lethal, with a fatality rate that is 80% or higher. Finally, friendly personnel can be protected with suitable antibiotics.

A mass attack using anthrax would require the creation of aerosol particles of 1.5 to 5 micrometres. Too large and the aerosol would be filtered out by the respiratory system. Too small and the aerosol would be inhaled and exhaled. Also, at this size, nonconductive powders tend to clump and cling because of electrostatic charges. This hinders dispersion. So, the material must be treated with silica to insulate and discharge the charges. The aerosol must be delivered so that rain and sun does not rot it, and yet the human lung can be infected. There are other technological difficulties as well.

Diseases considered for weaponization, or known to be weaponized include anthrax, Ebola, Bubonic Plague, Cholera, Tularemia, Brucellosis, Q fever, Machupo, Coccidioides mycosis, Glanders, Melioidosis, Shigella, Rocky Mountain Spotted Fever, Typhus, Psittacosis, Yellow Fever, Japanese B Encephalitis, Rift Valley Fever, and Smallpox. Naturally-occurring toxins that can be used as weapons include Ricin, SEB, Botulism toxin, Saxitoxin, and many Mycotoxins.

Attacking crops and animals

Biological warfare can also specifically target plants to destroy crops or defoliate vegetation. The United States and Britain discovered plant growth regulators (i.e., herbicides) during the Second World War, and initiated a Herbicidal Warfare program that was eventually used in Malaya and Vietnam in counter insurgency. Though herbicides are chemicals, they are often grouped with biological warfare as bioregulators in a similar manner as biotoxins.

The United States developed an anti-crop capability during the Cold War that used plant diseases (bioherbicides, or mycoherbicides) for destroying enemy agriculture. It was believed that destruction of enemy agriculture on a strategic scale could thwart Sino-Soviet aggression in a general war. Diseases such as wheat blast and rice blast were weaponized in aerial spray tanks and cluster bombs for delivery to enemy water sheds in agricultural regions to initiate epiphytotics (epidemics among plants). When the United States renounced its offensive biological warfare program in 1969 and 1970, the vast majority of its biological arsenal was composed of these plant diseases.

Attacking animals is another area of biological warfare intended to eliminate animal resources for transportation and food. In the First World War German agents were arrested attempting to inoculate draft animals with anthrax, and believed responsible for outbreaks of glanders in horses and mules. The British tainted small feed cakes with anthrax in the Second World War as a potential means of attacking German cattle for food denial, but never employed the weapon. In the 1950s the United States had a field trial with Hog Cholera.

Protective measures

The primary civil defense against biological weaponry is to wash one's hands whenever one moves to a different building or set of people, and avoid touching door knobs, walls, the ground and one's mouth and nose. Washing literally sends the germs down the drain.

More exotic methods include decontamination, usually done with household chlorine bleach (5% solution of sodium hypochlorite). One useful decontamination is to leave shoes in an entranceway and make people wade and handwash in a footbath of bleach. Another useful technique is to periodically decontaminate floors and door knobs.

Medical methods of civil defense include stockpiles of antibiotics and vaccines, and training for quick, accurate diagnosis and treatment. Many weaponized diseases are unfamiliar to general practitioners.

Positive pressure shelters are possible but not cost-effective except for the most important installations. This is because in most attacks, the agent will disperse in a long narrow ellipse downwind from the release point. Persons outside the ellipse will not be affected except by secondary infection. Persons within the release ellipse cannot be helped by civil defense measures. They need medical diagnosis and treatment as soon as possible.

The role of public health departments and disease surveillance

It is important to note that all of the classical and modern biological weapons organisms are animal diseases, the only exception being smallpox. Thus, in any use of biological weapons, it is highly likely that animals will become ill either simultaneously with, or perhaps earlier than humans. Indeed, in the largest biological weapons "accident" known -- the anthrax outbreak in Sverdlovsk (now Yekaterinburg) in the Soviet Union in 1979, sheep became ill with anthrax as far as 200 kilometers from the release point of the organism from a military facility in the southeastern portion of the city (known as Compound 15 and still off limits to visitors today).

Thus, a robust surveillance system involving human clinicians and veterinarians may identify a bioweapons attack early in the course of an epidemic, permitting the prophylaxis of disease in the vast majority of people (and/or animals) exposed but not yet ill. For example in the case of anthrax, it is likely that by 24 -36 hours after an attack, some small percentage of individuals (those with compromised immune system or who had received a large dose of the organism due to proximity to the release point) will become ill with classical symptoms and signs (including a virtually unique chest X-ray finding, often recognized by public health officials if they receive timely reports). By making this data available to local public health officials in real time, most models of anthrax epidemics indicate that more than 80% of an exposed population can receive antibiotic treatment before becoming symptomatic, and thus avoid the high mortality of the disease.

Biological History