Team:Queens Canada/Safety/Bioterrorism

Safety to both iGEM researchers and the general public has been a concept stressed throughout iGEM 2011. When examining biobricks, teams are encouraged to question the possibilities of potential misuse and the threat to security. A common argument is that researchers, such as iGEM participants, cannot be responsible for the modification of their biobricks for malicious misuse or the general approach to making synthetic biology more accessible.

Our 2011 team was interested in exploring the possibilities of potential misuse in much greater detail. As a new approach to human practices, we examined the threat of, and response to, synthetic biology under malicious intent, or bioterrorism.

Our team envisions an international co-operative effort to limit the possibility of bioterrorism. Similar to 'tiger team's in the aerospace industry, whose primary task was to identify every possible source of error in a spacecraft, an antiBT task force would begin with a preventative approach. The purpose of an antiBT task force would be to imagine every conceivable synthetic biology device that could be used for terrorist applications and then to design a countermeasure. Of course, this would have to be done entirely in secret to avoid giving inspiration to the enemy.

What would the antiBT tiger team require? There would need to be a think tank composed of experts in the biological sciences trustworthy enough to be given security clearance. A well-equipped laboratory would be needed to design and test the effectiveness of the countermeasures designed by the team. Given the complex nature of synthetic biology and the global ramifications of genetic engineering, such a team would need to be an international co-operative.

The antiBT task force should design and produce a variety of bioterrorism countermeasures. First, there are the standard countermeasures to a biological attack, vaccines and antibiotics. Anthrax and smallpox are thought to be the most likely candidates for use in a bioterrorist attack [1]. So, a sufficient stockpile of vaccinia virus vaccine (for smallpox) and anthrax vaccine adsorbed (AVA) to immunize a significant portion of the population would be ideal. Also, there should be sufficient cyprofloxin and doxycycline (anthrax antibiotics) to administer to all victims of a bioterrorist attack. Currently, Canada’s stockpile of such vaccines and antibiotics may not be sufficient to deal with all victims of a bioterrorist incident. It may be necessary for the antiBT task force to pioneer more efficient ways to make the vaccines and antibiotics.

New techniques might involve synthetic biology, which has been used by Ro and colleagues to cheaply, efficiently, and quickly produce the antimalarial drug artemisinin [2]. E. coli were equipped with heterologous enzymes from the bacterium S. cerevisiae, which enabled the E. coli to produce artemisinic acid, an immediate precursor of artemisinin, from acetyl-CoA. Acetyl-CoA is a TCA cycle intermediate produced naturally by E. coli. In traditional organic synthesis, the products of each synthetic step have to be isolated and purified before the beginning of the next step. A key advantage of an engineered bacterial chassis is that isolation and purification are unnecessary. Also, the conventional approach to isolating artemisinin from its natural producer, the Artemisia annua plant, is rate-limited by the availability of the plant. Bacterial production of artemisinin, by contrast, is limited by a facility’s capacity to produce E. coli, which is much less expensive than A. annua. The antiBT task force should pursue similar metabolic engineering approaches for the development of antibiotics for anthrax and other pathogens.

Another issue with stockpiling is that vaccines and antibiotics will eventually expire, requiring constant replenishment. It would be useful for the antiBT task force to develop a better system for storing vaccines to increase their longevity. Alternatively, it may be a better idea to design an apparatus capable of quickly producing a large quantity of vaccine. This system would not be used except in the wake of a bioterrorist attack. Such a system would eliminate the problem of expiry and ensure that no vaccine is produced wastefully. An apparatus based on engineered E. coli cells might have the capacity to produce vaccines and antibiotics quickly and flexibly.

Novel vaccine and drug discovery would be also be worthy endeavours for the antiBT task force. There is an emerging understanding that synthetic biology can be used to accelerate the drug discovery process. Traditionally, organic chemistry methods have been used to isolate natural products that are useful as human therapeutics. However, those natural products likely evolved for a purpose other than fighting disease in humans. Thus, although effective, they may not be ideally suited for human therapeutics. Terpenes, for instance, have numerous applications as antifungal and anticancer agents [3]. However, the use of synthetic biology to generate novel families of terpenes may lead to the discovery of novel or more effective medicines. One approach is to outfit E. coli cells with a variety of enzymes relevant to terpene production. Combinatorial expression of these enzymes may result in a transgenic host capable of producing new terpenes for drug discovery [4]. The antiBT task force could apply a similar approach to drug discovery with other families of compounds.  

Synthetic biology can also inform innovations in vaccine delivery systems. Engineered bacterial chassis can be used to more efficiently deliver drugs to a particular cell or tissue type. Traditional vaccines are administered through the skin and induce a systemic immune response [6]. But, many pathogens use mucosal tissues as a site of entry, and a mucosal immune response may be more appropriate [6]. In the case of bioterrorism, where pathogens are often delivered in aerosol form, a vaccine that induces a mucosal immune response would be especially useful. The issue with mucosal vaccines is that antigens delivered to mucosal surfaces tend to evoke weak immune responses due to poor absorption [6]. To increase absorption, the vaccine could be loaded into a bacterial chassis engineered to permeate mucosal membranes. Such a system would increase the efficiency of vaccine delivery. Work on this kind of bacterial chassis would contribute to bioterrorism preparedness and healthcare in general.

Synthetic biology could be used to design a novel pathogen with increased antibiotic resistance. How could the antiBT task force go about circumventing this increased resistance? Inspiration can be taken from the literature on superbugs. One approach is to tackle the pathogen’s mechanism of resistance. The antiBT task force would have to perform experiments to determine the new mechanism of resistance and way to counteract it. Traditional antibiotics used in conjunction with a countermeasure to the increased resistance should prove effective [5]. For example, some microbes have developed resistance to the class of antibiotics called β-lactams. Resistant bacteria produce enzymes called β-lactamases which hydrolyze β-lactam antibiotics [5]. However, substances like clavulanic acid are inhibitors of β-lacamases. So, adminstration of clavulanic acid along with β-lactams can combat β-lactam resistant bacteria [5]. In the same vein, scientists in the antiBT task force should examine the antibiotic resistance engineered into a pathogen and find a drug to circumvent that resistance.

The creation of an international regulatory body associated with the antiBT could be used to avoid production of dangerous DNA. It would be useful to have a system in place where companies that produce PCR primers flag orders for pathogenic genes. Those red flags could be sent to the antiBT task force and investigated for potential misuse. It may be difficult to get the support of all primer companies, who may wish to guarantee anonymity to their clients. To make the system truly effective, it would also be necessary to have international cooperation between the primer-producing companies of all nations.

The initial stages of a bioterrorist attack may go unnoticed. This is because pathogens can be released silently and lie dormant in the victim for a period of time. Conventional warfare can be loud and gory, but biological warfare can be stealthy and insidious. A quick and effective response to a bioterrorism crisis depends on the preparedness of the medical community. Doctors and nurses are usually not accustomed to biological warfare and may not know what warning signs to look for. Pathogens like anthrax and smallpox do not usually figure in differential diagnosis, and therefore symptoms of these agents may be attributed to other conditions [6]. If this happens, a significant number of cases need to accumulate before it is even realized that a bioterrorist attack has taken place. Patients may not be quarantined in time to prevent the spread of the unfamiliar pathogen. Authorities may not be alerted to the crisis quickly enough to mount an effective response. Since first news of a bioterrorist crisis would likely come from a hospital, it is important for doctors to have a precise knowledge of what signs and symptoms to look for.

The antiBT task force should offer a training course to the medical community. The course should act as a refresher in the signs and symptoms of likely bioterrorist agents like anthrax and smallpox. It should also cover the methods by which those conditions are diagnosed, proper treatment, and quarantine protocols to prevent the spread of the pathogen to other patients [6]. It should cover the legal issues of imposing quarantine on a patient and allowing loved ones to enter and leave the hospital. The responsibility to alert the authorities to a bioterrorist incident should be emphasized. Physicians taking the course should be trained to deal with the media without inciting a panic.

Once the medical community becomes aware of a bioterrorist incident, police and government must react quickly. It is not difficult to envision unnecessary panic on account of miscommunication between hospital staff, levels of government, the police, and the media. Confusion, inconsistency, and poor decision-making might impede a proper response to the incident. The point of a bioterrorism incident is also to cause fear, break down the social order, and shake faith in the government [7]. The antiBT task force should have a working response plan in place to make sure the response is carried out smoothly. The plan might be divided into steps and look something like the following:

Step 1: Confirm that a bioterrorist incident has occurred.
Step 2: Quarantine all patients and those with whom they have been in contact.
Step 3: Trace the attack back to its source, determine how many people have been exposed, and vaccinate as many of those people as possible.
Step 4: If the contagion is spreading, dispense vaccines and antibiotics to those at highest risk. Supplies would have to be dispensed judiciously.
Step 5: Maintain order at hospitals and other locations where vaccines and antibiotics are being dispensed to avoid rioting.
Step 6: Work with the media to ensure accurate reporting of medical facts. Lay misinterpretations of technical statements can lead to unnecessary panic.
Step 7: Determine who is responsible for the attack.

Complexity within and between these steps would have to be worked out in detail for a particular location and type of bioterrorist incident. Although a clear plan would help to increase the efficiency of the response to a bioterrorist attack, the role of chance is difficult to account for in advance. The antiBT task force should be capable of dealing with the unexpected in a calm, rational and flexible way. The overarching goal of the antiBT task force in an emergency situation would be to coordinate the efforts of doctors, government, and the media.

Responses to imagined scenarios are important, but the antiBT task force should also be equipped to deal with real bioterrorism incidents. A key issue in counter bioterrorism is the ability to distinguish between the intentional and unintentional release of pathogens [8]. This could be done by investigating the site in which the pathogenicity was detected. Does the pattern of release fit an accident or a planned attack? Also, the task force should discern the role of synthetic biology in the attack. In the case of a bacterial or viral pathogen, are there any traits present that distinguish it from wild-type? Is there evidence of an extrachromosomal array? Has the genome of the organism been modified? Can the organism be classified as a known species or is it something distinct? Answers to these questions would require a laboratory with BSL Level 3 or Level 4 clearance.

Epidemiological tools can be helpful in distinguishing an intentional attack from an accidental release [8]. An epidemiological curve is drawn on a plot with time on the x-axis and number of cases on the y-axis. Normally, the curve gradually increases to a peak, and then decreases. In the case of a bioterrorist attack, infection comes from a point source, producing a compressed epidemiological curve [8]. A second peak might also appear as infected persons contaminate a second generation of sufferers. However, a similar pattern would be observed in the case of a food-borne infection outbreak. So, epidemiological tools should be used in conjunction with other evidence to yield conclusive results.

The antiBT task force should have laboratories at its disposal. These laboratories should be tailored to quick assessment of a pathogen used in a bioterrorist attack. Equipment should go beyond those used by hospital diagnosticians, because the laboratory should be able to distinguish the influence of synthetic biology on the pathogen. So, the tools of molecular biology should also be present. The lab should have BSL Level 4 clearance to make sure it is capable of dealing with all conceivable pathogens that could be used in bioterrorism incident.

Distribution of what would likely be a limited supply of vaccines and antibiotics would also be important. Areas of highest risk (those who were directly exposed to the attack, anyone they may have had contact with, medical staff, and higher risk groups like children or the elderly) would have to be identified and given priority vaccination.

1. Russell, P.K. (1999). Vaccines in civilian defense against bioterrorism. Emerging Infectious Diseases, 5(4):531-533.
2. Ro, D., Paradise, E., Ouellet, M. et al. (2006). Production of the antimalarial drug precursor artemisinic acid in engineered yeast. Nature, 3:940-943.
3. Chosla, C., and Keasling, J.D. (2003). Metabolic engineering for drug discovery and development. Drug Discovery,
4. Garmory, H.S., Leary, S.E., Griffin, K.F. (2003). The use of live attenuated bacteria as a delivery system for heterologous antigens. Journal of Drug Targeting, 11:471-9.
5. Wright, G.D. (2000). Resisting resistance: new chemical strategies for battling superbugs. Chemistry & Biology, 7(6):127-132.
6. Bartlett, J.G. (1999). Applying lessons learned from anthrax case history to other scenarios. Emerging Infectious Diseases, 5(4):561-563.
7. O'Toole, T. (1999). Smallpox: An attack scenario. Emerging Infectious Diseases, 5(4):540-546.
8. Pavlin, J.A. (1999). Epidemiology of bioterrorism. Emerging Infectious Diseases, 5(4):528-530.