Bioterrorism
Bioterrorism
History and Scientific Foundations
Introduction
After years of “back burner” low priority research, work on defensive measures against bioterrorism began in earnest in the United States soon after the anthrax attacks in 2001. Scientists are now developing strategies designed to protect the United States against a potentially limitless variety of biological weapons. The psychological impact of the anthrax attacks of late 2001 was enormous compared to the number of people actually killed and sickened during the episode. This is in keeping with the pattern of effective terror tactics in which expenditures of time, effort, and funds can be minimal, but impact on the target population is maximized.
History and Scientific Foundations
Since 2001, most defensive activity against bioterrorism threats has been focused on preventing or combating known “Class A” threats, including the organisms that cause anthrax, plague, smallpox, tularemia, and viral hemorrhagic fevers, as well as botulinum toxin. Activity to develop new drugs and vaccines is budgeted under Project Bioshield, which is directed by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC).
Bioterrorism agents are essentially identical to biological warfare agents. Such agents may be classified operationally, as deadly or incapacitating agents, and as agents with or without the potential for secondary transmission (the ability to spread disease from one person affected by bioterrorism to another who was not exposed during the attack). Bioterrorism agents can also be classified according to their intended target, as when they are intended to sicken or kill people, animals, or vegetation such as crops; and according to type, including replicating pathogens (duplicating disease-causing organisms such as viruses, bacteria, or fungi), toxins, or biomodulators (immune system altering agents). Replicating pathogens and toxins are recognized as the greatest current threats.
Applications and Research
Smallpox
Although many pathogens could be used to attack the U.S. population, only a few, including the smallpox virus, could cause illness or panic that could overwhelm existing medical and public health systems. The WHO authorizes two laboratories in the world to maintain stores of smallpox virus for research purposes, and authorities fear that additional smallpox virus may exist hidden away in laboratories other than the two WHO-designated repositories.
A new outbreak of smallpox could spread rapidly. The CDC strategy for controlling a new outbreak of smallpox incorporates principles that were used 30–40 years ago in eradicating the disease and have proven their effectiveness. They are based on knowledge that smallpox is mostly transmitted by close, face-to-face contact with infected individuals, while only a few cases could be transmitted by dry or aerosolized particles in close proximity to persons with the disease. New cases develop two weeks after exposure and take another two weeks to progress to pustules and scabs, giving a newly aware medical community some time to respond.
Smallpox vaccine is a live-virus vaccine composed of vaccinia virus that induces antibodies that also protect against smallpox. Smallpox vaccine production ceased in the early 1980s and current supplies of smallpox vaccine are limited. The CDC expects that new vaccines manufactured using cell cultures will be available within two to four years under the Bioshield program. Limited new supplies of the current vaccine are being manufactured under Bioshield.
After several years of considering mass vaccination as an alternative, CDC has settled on a ring vaccination strategy to combat a new smallpox outbreak. This includes isolation of confirmed and suspected smallpox cases with tracing, vaccination, and close surveillance of contacts to these cases as well as vaccination of the household contacts of the smallpox cases. Ring vaccination takes advantage of the relatively low infectivity of smallpox and focuses currently scarce vaccine resources where they will do the most good, minimizing adverse events, including rare deaths that could occur during indiscriminate mass vaccination.
Anthrax
Anthrax is an infectious disease caused by a spore-forming bacterium, the spores of which are very persistent and hard to break down in the environment, which makes anthrax a persistent public health threat in spite of available treatment with familiar drugs.
There are three forms of anthrax infection: skin, gastrointestinal, and inhalational anthrax. Inhalational anthrax, with the highest death rates, occurs when spores are inhaled and infect the lungs. The treatments for all types of anthrax are the antibiotics ciprofloxacin, tetracycline drugs such as doxycycline, and some types of penicillin.
The anthrax vaccine is primarily given to people in the military and is only recommended for individuals considered to be at high risk of contracting the disease, such as scientists who handle anthrax bacteria. Current government efforts are focused on encouraging the development of new anthrax vaccines intended to prevent inhalational anthrax before and after exposure. The emergency response to anthrax consists of administration of antibiotics and spore cleanup by workers using personal protective equipment. Unvaccinated, exposed people and remediation workers begin taking preventative antibiotics at the time of their exposure and continue for at least 60 days.
Plague
Plague is caused by the bacterium Yersinia pestis. Bubonic plague is the most common type of naturally occurring plague, and is transmitted through the bite of an infected flea or exposure through a cut. Symptoms of bubonic plague include swollen, tender lymph nodes, headache, fever, and chills. If untreated, bubonic plague may result in death.
In pneumonic plague, the lungs are infected with the plague bacterium. People with pneumonic plague can transmit plague to other people, whereas bubonic plague cannot be spread from person to person. Antibiotics approved by the FDA to treat plague are streptomycin, doxycycline, and other tetracycline drugs. The public health response to pneumonic plague would be similar to that of anthrax, with the addition of quarantines that could impact sizable crowded geographic areas.
Impacts and Issues
The response to the 2001 anthrax attacks has been extensively analyzed as researchers attempt to model the optimal response to future attacks. The 2001 attacks were small-scale events, affecting a relatively few people in restricted geographic areas. In a recent study of a small-scale attack, Veterans Administration researchers conducted a cost-effectiveness analysis using a simulation model to determine the optimal response strategy for a small-scale anthrax attack against U.S. Postal Service distribution centers in a large metropolitan area. (A cost-effectiveness analysis compares the relative effectiveness of two or more alternatives in view of their costs and attempts to determine the best value for money.) The study compared three different strategies: (1) pre-attack vaccination of all U.S. distribution center postal workers, (2) post-attack antibiotic therapy followed by vaccination of exposed personnel, and (3) post-attack antibiotic therapy without vaccination of exposed personnel. The results showed that post-attack antibiotic therapy and vaccination of exposed postal workers is the most cost-effective response compared with post-attack antibiotic therapy alone. This was due to the greater prevention of death and disease when post-attack vaccination is combined with antibiotics. Pre-attack vaccination of all distribution center workers is less effective and more costly than the other two strategies. This is because vaccinating all postal employees would be very expensive, and the immunity conferred by the current vaccine is not perfect or always permanent, and the time between vaccination and an anthrax attack is indeterminate.
Some commentators have decried the resources and energy being poured into bioterrorism defense. According to this perspective, bioterrorism preparedness programs have wasted public health resources with little evidence of benefit. For example, several deaths and many serious illnesses have resulted from the smallpox vaccination program, but there is no clear evidence that any threat of smallpox exposure has existed since the eradication of the disease. Even the anthrax attacks were linked to secret U.S. military laboratories; without these laboratories the attacks probably would not have been possible. The huge effort to prepare the country against bioterrorist threats is seen by some critics as a great distraction from the need to allocate public health resources to address other health needs, and has been conducted at the expense of some vital programs.
Nevertheless, the anthrax attacks did demonstrate the havoc that malign individuals could wreak with sufficient determination, access to pathogens, and laboratory resources. As public protection will always be the primary responsibility of government, leaving the population totally unprepared for the eventuality of bioterrorism is simply not an option in the post-9/11 world. Accordingly, The Center for Law and the Public's Health at Georgetown and Johns Hopkins Universities drafted the Model State Emergency Health Powers Act (MSEHPA or Model Act) at the request of the CDC. The Model Act provides states with the powers needed to detect and contain either bioterrorism or a naturally occurring disease outbreak. To this extent, bioterrorism preparedness appears in sync with more conventional public health preparedness. Legislative bills based on the MSEHPA have been introduced in most states. This legislative effort has uncovered problems of state law obsolescence, inconsistency, and inadequacy. Most current state laws provide inadequate public protection whether a disease outbreak would be natural or intentional. They often date back to the early twentieth century and predate the immense changes in public health science over the past half-century.
The Model Act is structured to support five basic public health functions to be facilitated by law: (1) preparedness, comprehensive planning for a public health emergency; (2) surveillance, measures to detect and track public health emergencies; (3) management of property, ensuring adequate availability of vaccines, pharmaceuticals, and hospitals, as well as providing power to abate hazards to the public's health; (4) protection of persons, powers to compel vaccination, testing, treatment, isolation, and quarantine when clearly necessary; and (5) communication, providing clear and authoritative information to the public. The act is also based on a legal framework to protect personal rights.
WORDS TO KNOW
PATHOGEN: A disease-causing agent, such as a bacteria, virus, fungus, etc.
QUARANTINE: Quarantine is the practice of separating people who have been exposed to an infectious agent but have not yet developed symptoms from the general population. This can be done voluntarily or involuntarily by the authority of states and the federal Centers for Disease Control and Prevention.
RING VACCINATION: Ring vaccination is the vaccination of all susceptible people in an area surrounding a case of an infectious disease. Since vaccination makes people immune to the disease, the hope is that the disease will not spread from the known case to other people. Ring vaccination was used in eliminating the smallpox virus.
TOXIN: A poison that is produced by a living organism.
Use of Spectroscopy in Identifying Pathogens
Traditional detection of pathogens such as bacteria and viruses involves serologic (blood) testing in which potential pathogens in a tissue sample from an infected patient are cultured in the laboratory, and various stains and reagents are made to react with proteins of the pathogen's outer membrane. This is a slow and laborintensive process. A new technique of rapidly identifying bacteria such as anthrax called desorption electrospray ionization recently developed at Purdue University could be used for homeland security. This technique enables the fast “fingerprinting” bacteria using a mass spectrometer. The analysis of bacteria and other microorganisms usually takes several hours. The spectrographic technique ionizes molecules outside of the spectrometer's vacuum chamber. Ionized molecules can then be manipulated, detected, and analyzed using electromagnetic fields. This technique is extremely sensitive, capable of detecting 1-billionth of a gram of a particular bacterium and identifying its subspecies, which is the level of accuracy required for detecting and monitoring infectious microorganisms. The technology can determine the subspecies and collect other information by observing the pattern of the pathogen's outer membrane proteins, and creates a sort of fingerprint as revealed by mass spectrometry. Such accuracy and timeliness makes the technology particularly apt for detecting bioterrorism agents, as word of an intentionally caused outbreak would need to be spread very soon after the appearance of suspected cases in order to prevent rapid transmission of the pathogen.
Involving the General Public in Preparedness
The public health emergency responses being fashioned by the CDC to a bioterrorist attack focus mainly on readying emergency and medical workers to cope with infection transmission, panic, and decontamination. While there has been some refinement in terms of how agencies and response personnel should coordinate their efforts, so far there have been few urgent instructions or preventive measures disseminated to the general public. On the other hand, promising new research on detection technologies, vaccines, and medicines to prevent or combat infections is now being funded under Project Bioshield.
Most bioterrorism policy discussion and response planning has been conducted among experts and has not involved much public participation. The capacity of the public to take an active role and even to lead in the response to bioterrorism is often discounted, or policymakers have assumed that local populations would get in the way of an effective response. This bias is based on fears of mass panic and social disorder. While no one really knows how the population will react to an extraordinary act of bioterrorism, experience with natural and technological disasters and disease outbreaks indicates that the public response would be generally effective and adaptive collective action. Therefore, the public should be viewed as a partner in the medical and public health response. Failure to involve the public in planning could hamper effective management of an epidemic and increase the likelihood of social breakdown. Ultimately, actions taken by nonprofessional individuals and groups could end up having the greatest impact on the outcome of a bioterrorism attack. Guidelines suggested for integrating the public into bioterrorism response planning include (1) treating the public as a capable ally in the response to an epidemic; (2) enlisting civic organizations in practical public health activities; (3) anticipating needs for home-based patient care and infection control; (4) investment in public outreach and communication strategies; and (5) ensuring that planning reflects the values and priorities of affected populations.
Primary Source Connection
In an excerpt for the following journal article, the authors argue for a greater role for the biomedical research community in defense efforts against bioterrorism. Bradley T. Smith, PhD, is a Fellow, Thomas V. Inglesby, MD, is Deputy Director, and Tara O'toole, MD, MPH, is Director, all at the Johns Hopkins Center for Civilian Biodefense Strategies, Baltimore, Maryland.
Biodefense R&D: Anticipating Future Threats, Establishing a Strategic Environment
INTRODUCTION
The ultimate objective of the U.S. civilian biodefense strategy should be to eliminate the possibility of massively lethal bioterrorist attacks. A central pillar of this strategy must be an ambitious and aggressive scientific research, development, and production (R&D&P) program that delivers the diagnostic technologies, medicines, and vaccines needed to counter the range of bioweapons agents that might be used against the nation. A successful biodefense strategy must take account of the rapidly expanding spectrum of bioweapons agents and means of delivery made possible by 21st century advances in bioscientific knowledge and biotechnology. Meeting this challenge will require the engagement of America's extraordinary scientific talent and investments of financial and political capital on a scale far beyond that now committed or contemplated. The purpose of this article is to provide a brief analysis of the current biomedical R&D&P environment and to offer recommendations for the establishment of a national biodefense strategy that could significantly diminish the suffering and loss that would accompany bioterrorist attacks. In the longer term, a robust biodefense R&D&P effort, if coupled to substantial improvements in medical and public health systems, could conceivably render biological weapons ineffective as agents of mass lethality.
THE PROBLEM: 20TH AND 21ST CENTURY BIOWEAPONS
The advantage is now firmly with those who would seek to deploy offensive bioweapons; the state of biodefense is relatively weak. Following the terrorist attacks of 2001, the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health (NIH) received $1.7 billion to fund biodefense research projects. NIAID has since established a “roadmap” describing the scientific research needed to devise new “countermeasures” (i.e., diagnostic technologies, therapeutic drugs, and vaccines) for the pathogens thought to be the bioweapons agents of greatest concern. Much of the NIAID roadmap has, appropriately, focused on developing countermeasures for the six CDC Category A bioweapons threats (anthrax, smallpox, plague, botulism, tularemia, and the viral hemorrhagic fevers) for which there are striking gaps in available countermeasures…, and a selection of other bioweapons threats on the CDC's Category B and C lists (collectively termed “20th century bioweapons” in this article).
Growing numbers of people in the scientific community now recognize that looming just ahead is a far more daunting array of potential engineered bioweapon agents (collectively termed “21st century bioweapons” in this article). The life sciences are at the beginning of a revolutionary period. Scientific understanding of living systems and how to manipulate them is expanding exponentially, fueled by advances in computerization, the global dispersion of bioscientific expertise as well as biological databases, and substantial economic investment in biomedical and agricultural research and product development.
A prime example of these powerful advances was the identification in 2001 of the approximately 40,000 genes in the human genome. Scientists are rapidly learning how to translate this genomic “parts list” into a sophisticated understanding of how specific genes control human biological systems in the body. Such discoveries will bring great benefit to humankind, but they will also allow the development of a new constellation of powerful 21st century bioweapons.
There are already countless portents of the coming power of bioscience and how it will propel bioweapons developments. Scientists have shown that it is possible to create strains of the bacterium that causes anthrax to be resistant to the most powerful existing antibiotics. They have demonstrated the capacity to make viruses that can overcome vaccine-induced immunity. Viruses can be genetically modified to increase their ability to kill infected cells, or to become capable of attacking entirely new target species. Viruses and bacteria can be manipulated in ways that make them better able to survive environmental stress and to be disseminated over distances in the air as weapons. Technologies already exist that could be used to protect pathogens from detection or destruction by the human immune system. These are only a small sample of the developments ahead on the bioscience landscape.
The “dual use” aspect of bioscience does not pertain only to specific, isolated technological applications, as is the case in nuclear weapons work. Rather, it is biological knowledge itself that is the source of the power that can be applied toward beneficent or malevolent ends. The knowledge needed to engineer a more lethal viral or bacterial bioweapon is essentially the same as that needed to understand how that virus or bacteria causes disease and how to create an effective vaccine against it. The distinction between good biology and its “dark side” lies only in intent and application. With rare exception, it will be very difficult to sequester new bioscientific knowledge that might be applied to building biological weapons without simultaneously harming beneficial biomedical research and essential biodefense R&D&P.
Given the size, momentum, and global dissemination of the bioscientific enterprise and the great demand for the medical and agricultural products being created, the rapid global advance of bioscience is essentially unstoppable. A successful biodefense R&D&P strategy must accept that the growth and international diffusion of bio-scientific knowledge and technologies will continue at a phenomenal pace and must seek to leverage these powerful forces against the bioterrorist threat. …
CONCLUSION
The full power of the nation's biomedical research, development, and production enterprise is not yet engaged in biodefense, and given the current environment, funding levels, priorities, and lack of clear vision for the biodefense R&D&P program, large numbers of the best biomedical scientists are unlikely to engage. Current biodefense initiatives, when compared to other U.S. government efforts to address top national security threats, suggest that the U.S. government either does not yet understand the grave nature and scope of the bioterrorist threat or is not prepared to commit fully to a robust biodefense research, development, and production effort. This must change if the nation is to counter the coming bioweapons threat and set the course to eliminate bioweapons as weapons of mass lethality.
Editor's note: Referenced citations omitted.
Bradley T. Smith, Thomas V. Inglesby, Tara O'toole
BRADLEY T. SMITH, THOMAS V. INGLESBY, ANDTARAO'TOOLE. “BIODEFENSE R&D: ANTICIPATING FUTURE THREATS, ESTABLISHING A STRATEGIC ENVIRONMENT.” BIOSECURITY & BIOTERRORISM. 1(3):193–202, 2003.
See AlsoWar and Infectious Disease; Public Health and Infectious Disease.
BIBLIOGRAPHY
Books
Fong, I.W., and Kenneth Alibek, eds. Bioterrorism and Infectious Agents: A New Dilemma for the 21st Century. New York: Springer, 2005.
Periodicals
Cohen H.W., R.M. Gould, V.W. Sidel. “The Pitfalls of Bioterrorism Preparedness: the Anthrax and Smallpox Experiences.” Am J Public Health, (2004): 94:1667–1671.
Glass T.A., M. Schoch-Spana. “Bioterrorism and the People: How to Vaccinate a City against Panic.” Clinical Infectious Diseases (2002) 34:217–23.
Gostin L.O., J.W. Sapsin, S.B. Teret, et al. “The Model State Emergency Health Powers Act: Planning for and Response to Bioterrorism and Naturally Occurring Infectious Diseases.” JAMA (2002): 288:622–628.
Web Sites
Centers for Disease Control and Prevention (CDC). “Bioterorism.” <http://www.bt.cdc.gov/bioterrorism/> (accessed June 13, 2007).
Kenneth T. LaPensee