Essay
Mutually assured pathogenicity CHARLES S. COCKELL
Planetary and Space Sciences Research Institute, Open University, Milton Keynes MK7 6AA, UK
The development and use by terrorist organisations and nation states alike of category A biological agents presents one of the most profound security threats of our time.1 The challenge of prevention has been made more acute by the increasing accessibility of molecular biological techniques and expertise, and by the proliferation of commercially available ‘kits’ which allow genetic manipulation to be undertaken with quite simple laboratory apparatus. Preventing the spread and use of biological weapons can be addressed by various means.2 These can be divided broadly into four principal strategies: (1) the implementation of international protocols against the weaponisation of micro-organisms and the subsequent verification of such protocols; (2) the establishment of regimes of deterrence against the use of biological weapons; (3) effective defences against the import of dangerous agents; and finally, (4) a response system for dealing with the public health implications of the intentional release of a biological agent. The first three approaches represent forms of ‘prevention’, to use a medical analogy, the last a form of ‘cure’. On the assumption that it is preferable to prevent the use of biological weapons in the first place, it is prevention that is my focus here. Verification of the control of biological weapons is widely acknowledged to be virtually impossible. Nuclear weapons are somewhat easier to manage, on account of the sophisticated and bulky apparatus required to produce weapons-grade uranium.3 In contrast, the small size and increasing sophistication of molecular biology laboratories, together with the fundamentally simple principles of microbiology, allow not merely growth of pathogens in the laboratory, but their large-scale manufacture in unverifiable secrecy. Although it is not necessarily a simple task to engineer increased pathogenicity into micro-organisms, let alone to weaponise them in a form suitable for dispersal, as the expertise in molecular biology spreads so this capability is likely to become increasingly widespread. There certainly exist straightforward approaches for reducing the spread of biological weapons expertise and the means of weaponising micro-organisms. Self-policing by scientists and journal editors of the type of information entering the public domain in peerreviewed journals would be one;4 tight control of pathogenic organisms being sold by culture collections is another. It seems to me, however, that such procedures merely delay the spread of biological weapons expertise – they cannot actually prevent it. Much of the relevant information on molecular biological methods is already in the public domain. DOI 10.1179/030801807X183597 INTERDISCIPLINARY SCIENCE REVIEWS, 2007, VOL. 32, NO. 1 7 © 2007 Institute of Materials, Minerals and Mining. Published by Maney on behalf of the Institute
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Further, the acquisition of pathogenic strains of micro-organisms would be possible with sufficient determination. Plague, haemorrhagic fevers, anthrax and other category A infectious agents could be isolated by a focused microbiologist or group of microbiologists from suitable environmental samples. Active defence against biological weapons, for example screening of imported biological samples and materials, is potentially effective at reducing the threat, but by their very nature biological weapons are small, constructed as they are from micro-organisms. No defence system can hope to completely prevent cross-border movement of microorganisms by determined groups. Thus we are left with deterrence. Although from a weapons verification point of view biological weapons do indeed present a quandary much worse than chemical or nuclear, we should be looking to other characteristics of biological weapons to understand where they sit within a framework of weapons deterrence. Unless they are used in a protracted and dispersed attack (an unlikely scenario for terrorist organisations or states with limited supplies of weapons), chemical and nuclear weapons, no matter how large their yield, have localised effects on human beings. Radioactive clouds from nuclear weapons can spread, as can chemical weapon clouds, but nonetheless the effects of limited use are generally localised, at least from the users’ point of view. Biological weapons on the other hand possess the property that the more pathogenic they are, the less containable and localised their effects will be. For instance, malicious use of salmonella (the poisoning of 751 Oregon residents by the Bhagwan Shree Rajneesh cult in 1984 being an example) affects only those people who eat the food that has been deliberately contaminated. The release of a vaccine-resistant strain of smallpox or a highly contagious aerosol-carried form of haemorrhagic fever, by contrast, could be potentially catastrophic. There is one valuable and, in the realm of deterrence, unique property of highly pathogenic biological agents: they are highly likely to kill some of the very people whose cause the perpetrators of an attack are seeking to represent. In other words they have the property, to coin a phrase, of ‘mutually assured pathogenicity’. Though this concept has parallels with the nuclear doctrine of Mutually Assured Destruction (MAD),5 there are important differences. To be effective as a deterrent, MAD requires the threat of massive retaliatory use of nuclear weapons by enemy forces. Mutually assured pathogenicity does not require the threat of such a response. Highly pathogenic agents are a potential threat to the smallest group of people – the perpetrators as much as the targets – and so, unlike nuclear weapons, the mutuality principle can work at a very local level, and is relevant to the threat we currently face. As suicide bombings attest, it is hopeless to expect that terrorist organisations will be concerned about releasing an agent that boomerangs against them personally, but it is not unreasonable to expect that they, or similarly inclined nation states, might be concerned about releasing an agent that could end up killing large numbers of the people whose cause they wished to represent. Furthermore, such actions would be likely only to strengthen their adversaries’ positions. Imagine, for example, an attack by a terrorist organisation against the UK using vaccine-resistant smallpox; an attack which ultimately had the INTERDISCIPLINARY SCIENCE REVIEWS, 2007, VOL. 32, NO. 1
Mutually assured pathogenicity
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potential to cause a pandemic. Many areas of the world (perhaps including the homes of the terrorists and of those with whom they identified), being less prepared for a biological attack and having more limited access to potential vaccines, might suffer more. The consequence would be that the perpetrators would in fact strengthen the hand of the country they were seeking to undermine. Even a terrorist organisation might well be deterred from causing a pandemic with such an uncertain result. Mutually assured pathogenicity results in a self-regulating defence situation. The less pathogenic an agent is, the lower is the threat of mutually assured pathogenicity and thus the more effective the attack, at least from the perpetrators’ point of view. However, at the same time, the lower will be the national threat and the higher the probability of satisfactory containment. The October 2001 anthrax letter attacks in the United States were an example of an attack where the perpetrators were safe from infection, but concomitantly anthrax attacks of that type are easily contained with a rapid public-health response.6 The more pathogenic an agent, the more likely it is that the agent will spread, killing members of the constituency the perpetrators seek to represent, and thus limiting the overall effectiveness of an attack. Of course, mutually assured pathogenicity would be ineffective against a group that sought to represent no one, merely wishing to cause mass casualties for the sake of it. Though this is not a completely implausible scenario, most groups seeking a weapons capability are indeed motivated by a political or religious agenda that involves representing some particular constituency. Although the threat of the use of biological weapons is likely now to be ever present, and the future spread of molecular biological techniques will be wide and unverifiable, it may be argued that the use of biological agents capable of causing epidemics or pandemics is made much less likely by the principle I have outlined here of ‘mutually assured pathogenicity’. NOTES 1. H. C. Lane, J. La Montagne and A. S. Fauci: ‘Bioterrorism: a clear and present danger’, Nature, 2001, 7, 1271–1273; A. S. Fauci: ‘Biodefence on the research agenda’, Nature, 2003, 421, 787; L. D. Prockop: ‘Weapons of mass destruction: overview of the CBRNEs (chemical, biological, radiological, nuclear, and explosives)’, Journal of the Neurological Sciences, 2006, 249, 50–54. Category A biological agents are agents with a high potential for adverse public health impacts and large-scale dissemination. They include anthrax, plague, smallpox, viral haemorrhagic fevers and botulism. 2. C. F. Chyba: ‘Toward biological security’, Foreign Affairs, 2002, 81, 122–136; J. Lederberg: Biological Weapons: Limiting the Threat; 1999, Cambridge, MA, MIT Press. 3. C. F. Chyba and A. L. Greninger: ‘Biotechnology and bioterrorism: an unprecedented world’, Survival, 2004, 46, 143–162. The security threat associated with weapons-grade uranium is different, in that once produced, the volume required for a bomb is quite small and readily transportable, and so it then becomes susceptible to theft. 4. B. Rappert: ‘Responsibility in the life sciences: assessing the role of professional codes’, Biosecurity and Bioterrorism, 2004, 2, 164–174; C. N. Fraser and M. R. Dando: ‘Genomics and future biological weapons: the need for preventive action by the biomedical community’, Nature Genetics, 2001, 29, 253–256. 5. R. Perle: ‘Mutually assured destruction as a strategic policy’, American Journal of International Law, 1973, 67, 39–40. INTERDISCIPLINARY SCIENCE REVIEWS, 2007, VOL. 32, NO. 1
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6. R. Brookmeyer, E. Johnson and R. Bollinger: ‘Public health vaccination policies for containing an anthrax outbreak’, Nature, 2004, 432, 901–904; A. M. Friedlander: ‘Microbiology – tackling anthrax’, Nature, 2001, 414, 160–161.
Charles S. Cockell (
[email protected]) is Professor and Chair of Microbiology at the Open University, UK. He has written and edited six books including Impossible Extinction (2003, Cambridge University Press) about the survival of microbes after natural catastrophes, and most recently Space on Earth (2006, Palgrave Macmillan), which discusses shared ground between the aims of environmentalism and space exploration. Following doctoral study at the University of Oxford, he worked for NASA and the British Antarctic Survey. He has led expeditions to Mongolia and Indonesia, among other places, to study life in extreme environments.
INTERDISCIPLINARY SCIENCE REVIEWS, 2007, VOL. 32, NO. 1
