Bioterrorism – The silent threat from within

Humans like to think that they are the most successful species on the planet but it all depends on how you measure success. On the basis of total numbers and diversity it can be argued that bacteria and viruses are considerably more successful than Homo sapiens. There are currently 7.3 billion humans on the planet yet microorganisms outnumber us by several orders of magnitude. Take, for example, the human body which contains approximately 100 trillion cells, of which, only 1 in 10 are actually human. The vast majority are bacteria and other microorganisms which call our bodies home. Until relatively recently the relationship between bugs and humans has been dominated by the bacteria who exploit the human body as an ecologically friendly hotel and upon death as a larder. As long as this relationship is kept in balance everyone is happy, when this status quo is disrupted it is invariably the human that suffers.

In this context pathogenic bacteria can be considered in the same light as a hostile corporate takeover. The new team come in, causing massive disruption but eventually everything settles down into a new equilibrium. Unfortunately, the impact of this initial disruption can be massive. Take, for example, the pandemics caused by Yersinia pestis which peaked between 1347 and 1350, and reduced the world’s population from an estimated 450 million to between 350 and 375 million, in the 14th century. Since that time the incidence of Y. pestis-related deaths have decreased due to a number of factors including the way in which human communities organize themselves.

Thus microorganisms represent an ever-present danger and for this reason their use as a bioweapon strikes a deep chord especially in Western societies where the threat of infectious disease has largely been eliminated. This sense of fear is not helped by Hollywood and the entertainment industry which generates a steady diet of disaster movies in which global Armageddon at the hands of a deadly pathogen is an ever-present danger. But, what is the reality?

Bioterrorism is the intentional misuse of microorganisms and their toxic products. Indeed, humans are not the only target of bioweapons. Biological agents have been developed which target food animals, such as cattle, and food plants, such as rice. Bioweapons have the potential to be more devastating than conventional bombs and bullets due to their ability to reproduce and spread from person to person. This, coupled with their ability to be covertly introduced into a major urban centre, means they have the potential to infect significant numbers of susceptible individuals.

It has been estimated that a covert attack on a major US city with 1 kg of Bacillus anthracis spores would result in the infection of 1.5 million individuals, of whom 50,000 – 125,000 are likely to die if not promptly treated (Wein, et al., 2003). This many infected individuals are likely to overwhelm the healthcare resources of even the most advanced countries. It should also be borne in mind that these figures are for an organism which does not normally spread from person to person. An attack with a communicable pathogen, such as smallpox, could result in as many as 3 million infected individuals within two months and 1 million deaths (O’Toole, et al., 2002). These figures were generated by a US tabletop public health exercise called ‘Dark Winter’ which simulated the release of smallpox in Oklahoma City. It highlighted the many and varied challenges which would be faced by the authorities in combatting such an event not least of which was the breakdown of civil society prompted by the fear of infection.

The earliest historical event linked to a biological attack was the 14th century siege of Caffa in the Crimea when the bodies of plague victims were sent over the walls of the city . More recently, at least in terms of human history, there is evidence to suggest that Germans attempted to target horses and transport animals during the First World War using the bacterial agents; anthrax and glanders. One of these plots, which was led by a German officer named Anton Dilger, succeeded in establishing a covert bioweapons lab within 10 miles of the White House in Washington (Koenig, 2006). During the Second World War the pace of bioweapons research increased with the Allies investigating the utility of a number of biological agents such as B. anthracis. On the Axis side the primary focus on the German research effort was the development of chemical agents which included nerve agents, such as sarin. They appeared to have invested little effort into the development of biological weapons. In contrast their Japanese allies established a biowarfare research effort in Mongolia where they performed trials with weaponized agents against the civilian population and prisoners of war (Barenblatt, 2004).

Following the war, the destructive potential of biological weapons was recognized by a number of nation states who saw these agents as a cheaper alternative to nuclear weapons. Following the first Gulf War in 1991, the extent of the Iraq bioweapons programme was revealed by the United National Special Commission on Iraq (UNSCOM) who discovered evidence of B. anthracis and botulinum toxin-filled warhead and bombs (UNSCOM, 1999).

It was around this time that non-state terrorist groups began to investigate the feasibility of employing biological organisms as agents of terror. While the notorious Aum Shinrikyo doomsday sect carried out the infamous sarin gas attacks on the Tokyo subway in 1995 it may surprise many to know that two years earlier they had attempted to launch an anthrax attack (Keim et al., 2001). In June 1993, the cult sprayed a liquid suspension of B. anthracis from the roof of their headquarters building in Kameido, near Tokyo, Japan. They constructed a delivery system which pumped the liquid suspension of bacterial spores to an aerosol dispersal device located on the roof. Fortunately their knowledge of microbiology was not great and all they succeeded in doing was dispersing spores of an animal vaccine strain, and making a smell.

Unfortunately the anthrax mail attacks in the US amply demonstrated what could be achieved when the correct strain was used. While the loss of five lives to infection was a tragedy in itself the attacks had a far wider impact on the psychology of the people of the US and highlighted the ability of a small-scale bioterrorist attack to disrupt an advanced society (Atlas, 2002). Since then billions of dollars have been invested in research into biodefence and into defence and security in general.

So why has a major bioterrorist event not happen since 2001? Is it a consequence of the authorities being better prepared as a result of the billions that have been invested in this area? In my opinion it is more likely to be the case that bombs and bullets are much easier to get hold of and to operate in a manner which does not kill the terrorists before they have performed their misguided acts. In contrast, the safe handling and manipulation of microorganisms at this moment in time is considerably more challenging but, this will not always be the case. Advances in modern sciences have reduced complex procedures, such as cloning genes, which were previously restricted to university labs to a level at which they can be performed as a leisure activity by citizen scientists (Baillie & Cooper, 2014). It is also now possible to buy all the equipment you need to set up a weapons lab from the Internet. Project Bacchus (1999–2000), run by the US Department of Defense, demonstrated the feasibility of acquiring on the open market the materials necessary to produce approximately 1 kg of refined, anthrax-like bacteria.

While this democratization of science is to be applauded it raises the spectre of unscrupulous individuals employing this new-found knowledge to the detriment of mankind. Indeed, whatever happens in the future it is sobering to consider that the bugs will always win!

Les Baillie
Cardiff University

Atlas, R. M. (2002). Bioterriorism: from threat to reality. Annu. Rev. Microbiol.,
Vol. 56, pp167–185.

Baillie, L., and Cooper, C. (2014). Agents of bioterror. Garage laboratories raise biosecurity risks. Jane’s Intelligence Review, Feb, pp50–53.

Barenblatt, D. (2004). A Plague upon Humanity: The Hidden History of Japan’s Biological Warfare Program. Published by Harper Collins.

Keim, P., Smith, K. L., Keys, C., Takahashi, H., Kurata, T., and Kaufmann, A. (2001). Molecular investigation of the Aum Shinrikyo anthrax release in Kameido, Japan. J. Clin. Microbiol., Dec, Vol. 39(12), pp4566–4567.
Koenig, R. (2006). The Fourth Horseman. One Man’s Mission to Wage the Great War in America. Published by PublicAffairs.

O’Toole, T., Michael, M., and Inglesby, T. V. (2002). Shining light on “Dark Winter”. Clin Infect Dis., Vol. 34(7), pp972–983.

Scasciamacchia, S., Serrecchia, L., Giangrossi, L., Garofolo, G., Balestrucci, A., Sammartino, G., et al. (2012). Plague epidemic in the Kingdom of Naples, Emerg. Infect. Dis. [serial on the Internet], Jan, pp1656–1658.

United National Special commission on Iraq. (UNSCOM) – Report to the Security Council – 25 January 1999.

Wein, L. M., Craft, D. L., and Kaplan, E. H. (2003). Emergency response to an anthrax attack. PNAS, April, Vol. 100(7), pp4346–4351.

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