Bioterrorism, Protective Measures

█ K. LEE LERNER

Bioterrorism is the deliberate use of microorganisms or the poisonous compounds that can be produced by some microbes as weapons. Bioterrorism can be a well-organized government sanctioned weapons development program, or can involve a small group of people dedicated to their particular cause.

In the past, the weapons employed by nations were more easily recognizable and defendable. For example, surveillance allows missile silos to be detected, and counter-strategies put in place to deal with the launch of the missiles. Microorganisms, however, by virtue of their small size can be readily hidden from detection. A vial of anthrax spores—small enough to conceal in a pocket—can be released into the ventilation system of a building.

The ability to protect against the use of biological weapons is becoming recognized as one of the paramount security issues facing nations such as the United States.

The need for protective measures against bioterrorism was dramatically evident in the aftermath of the September 11, 2001 terrorist attacks on the United States, when a lethal form of the anthrax bacterium that could be inhaled was mailed to U.S. government leaders, media representatives, and citizens. The form that readiness and response strategies should take is the subject of much public debate.

A range of protective options exist. These include the mass production and stockpiling of antibiotics (i.e., ciprofloxacin, which is normally effective against the bacterial agent of anthrax) and the resumption of offensive biological weapons programs by countries such as the United States (where offensive research was halted in 1968). However, no single solution will provide protection against the many potential biological weapons. Indeed, an argument has been made that a targeted response (e.g., broadly inoculating the public against the virus causing smallpox) might actually lower overall preparedness by diverting personnel and funding from fundamental research programs that could help spawn a variety of protective measures.

The various protective measures to bioterrorism can be divided into three general categories. These are strategic, tactical, and personal measures.

Strategic deterrence can involve international cooperation. For example, late in 2001, the United States and NATO (North Atlantic Treaty Organization) allies reaffirmed treaty commitments that the use weapons of mass destruction (i.e., biological, chemical, or nuclear weapons) against any member state would represent an attack against all NATO members. As of June 2002, this deterrence was pointed at states—in particular Iraq—that have programs to develop or use biological weapons, or which provide aid to bioterrorists.

Tactical measures involve the use of devices or weapons to detect or eliminate potential biological weapons. The United States has a variety of tactical non-nuclear options, which include precision-guided conventional thermal fuel-air bombs. In the 1990s military campaigns in the Gulf region, for example, these bombs were used to destroy facilities that were suspected of being factories for the production of biological warfare agents and weaponry.

Terrorist operations are enigmatic and elusive. As a result, these large-scale military responses offer protection against only the largest, identifiable, and targetable enemies. Such responses are inadequate when the hostility is due a small number of people operating in a clandestine way in other countries, or even citizens targeting their own country. For example, according to expert testimony before the Congress, for less than 10,000 U.S. dollars, a laboratory capable of producing spores of the anthrax bacterium could be built in the basement of a typical house. Surveillance of every structure in a country is beyond the scope of established security agencies and, in a democratic country, would severely curtail individual liberties.

Reestablishing offensive weapons programs is a contentious issue. An argument has been made that an offensive program would further the understanding of potential biological agents and weapons delivery mechanisms. However, many scientists and physicians argue instead that an offensive program is unneeded and could possibly be detrimental to the development of effective protective measures, because of the diversion of funding from less visible but vital preventative research. Resumption of an offensive bioweapons programs in the United States would violate the Biological Weapons Convention to which the United States is a signatory.

Rather than a polarized offensive-versus-preventative national policy, scientific bodies in the United States that include the National Institutes of Health and the Centers for Disease Control and Prevention (CDC) advocate a balanced and flexible scientific and medical response to the need to develop protective measures against the variety of disease causing pathogens in the arsenal of the bioterrorist.

Preparedness programs designed to allow a rapid response to bioterrorism also accompany the increased research. One example is the National Pharmaceutical Stockpile Program (NPS). The NPS stockpile of antibiotics, vaccines, and other medical treatment countermeasures is can be rapidly deployed to the site of a domestic attack. For example, in the aftermath of the deliberate release of Bacillus anthracis (the bacteria that causes anthrax) during the 2001 terrorist attacks, the United States government and some state agencies were able to quickly provide the antibiotic ciprofloxacin (Cipro) to those potentially exposed to the bacterium.

Following these bioterrorist attacks, increase funding for the NPS was authorized. The additional funds will help train medical personnel in the early identification and treatment of disease caused by the most likely pathogens.

Such steps are commendable, but will not provide comprehensive and effective protection to biological terrorism. Indeed, such protection may not be possible.

Advocates of increased research capabilities argue that laboratory and hospital facilities must be increased and modernized to provide maximum scientific flexibility in the identification and response to biogenic threats. The CDC has already established a bioterrorism response program that includes increased testing and treatment capacity. The plan also envisions an enhanced ability to recognize and respond to the illness patterns that are characteristic of the deliberate release of an infectious agent.

An informed and watchful public is a key element in early detection of biological pathogens. Knowing this, the CDC web site contains a list of potential biological threats. As of July 2002, approximately 36 microbes had been identified (e.g., Ebola virus variants, plague bacterium, etc.) as potential bioterrorist weapons.

Other protective and emergency response measures include the development of the CDC Rapid Response and Advanced Technology laboratory, a Health Alert Network (HAN), National Electronic Data Surveillance System (NEDSS), and Epidemic Information Exchange (Epi-X). These responses are designed to coordinate information exchange to enhance the early detection and identification of biological weapons.

The United States Department of Health and Human Services 1999 Bioterrorism Initiative committed funds to initiate or reinforce some of these protective measures. Following the September 11, 2001 terrorist attacks on the United States, the U.S. Congress more than doubled the previous funding for bioterrorism research. Soon thereafter, the Bioterrorism Preparedness and Response Program (BPRP) was created. The BPRP seeks to increase the number and capacity of laboratories that are capable of identifying pathogens and developing countermeasures to their use.

An essential component of a preventative response including effective therapeutic treatments is basic research into the biology and disease mechanisms of the disease causing microorganisms. In response to terrorist attacks, in February 2002, the U.S. National Institute of Allergy and Infectious Diseases (NIAID) undertook a review of current research efforts. The panel of experts convened for this task hopes to recommend research thrusts that will more effectively anticipate and counter potential terrorist threats. An immediate outcome of the panel's deliberations was an increased emphasis on basic research involving smallpox, anthrax, botulism, plague, tularemia, and viral hemorrhagic fevers.

In addition to medical protective measures, a terrorist biological weapon attack targeted at humans would, at a minimum, overburden medical infrastructure. Medical personnel and supplies would be in short supply. As well, the costs of responding to attacks would cause economic havoc. Alternatively, a biological weapon that spared humans but targeted domestic animals or crops could cause famine and economic ruin.

On a local level, cities and communities are being encouraged to develop specific response procedures in the event of bioterrorism. Most hospitals are now required to have response plans in place as part of their accreditation requirements.

Another aspect of prevention focuses on the drinking water supply of communities. Many microorganisms or their poisons readily dissolve in water, and so can be spread to a population virtually undetected. As well, water supplies and distribution systems have bee designed for efficiency of water disinfection and deliver, not for security. Because of this, many communities have placed extra security on water supply and treatment facilities. The U.S. Environmental Protection Agency (EPA) has increased monitoring and working with local water suppliers to develop emergency response plans.

It is beyond the scope of this article to discuss specific personal protective measures. Indeed, given the complexities and ever-changing threat, it would not be prudent to offer such specific medical advice. However, a number of general issues and measures can be discussed. For example, military surplus gas masks provide only the illusion of protection. They offer no real protection against biological agents, and should not be bought for that purpose. Personnel stockpiling of antibiotics is unwise. The potency of antibiotics such as Cipro declines with time. Moreover, the inappropriate use of antibiotics actually can lead to the development of bacterial resistance and a consequential lowering of antibiotic effectiveness.

On the other hand, a few days supply of food and water and the identification of rooms in homes and offices that can be temporarily sealed with duct tape to reduce outside air infiltration is a wise precaution.

More specific response plans and protective measure are often based upon existing assessments of the danger posed by specific diseases and the organisms that produce the disease. For example, Anthrax ( Bacillus anthracis ), Botulism ( Clostridium botulinum toxin), Plague ( Yersinia pestis , Smallpox ( Variola major , Tularemia ( Francisella tularensis , viral hemorrhagic fevers (e.g., Ebola, Marburg), and arenaviruses (e.g., Lassa) are considered high-risk high-priority. These agents do share a common trait of being easily spread from person to person. And, they all can kill many of those who are infected. But, the natures of the diseases they cause are very different. A response that is effective against one microorganism may well be useless against another.

The protective measures that are in place against smallpox and anthrax remain controversial. Vaccines against both diseases are available. However, both vaccines carry the risk of serious side effects. In the absence of a confirmed case of smallpox, the CDC's position is that the risks of resuming general smallpox vaccination out-weigh the potential benefits. Vaccine is available for use in a bioterrorist emergency, when the benefits of mass vaccination could well outweigh the risks of harm due to the vaccine. Moreover, vaccines delivered and injected during the incubation period for smallpox (approximately 12 days) convey at least some protection from the ravages of the disease.

Also controversial remains the safety and effectiveness of an anthrax vaccine used primarily by military personnel.

BOOKS:

Henderson, D.A., and T.V. Inglesby. Bioterrorism: Guidelines for Medical and Public Health Management. Chicago: American Medical Association, 2002.

Inglesby, Thomas V. "Bioterrorist Threats: What the Infectious Disease Community Should Know about Anthrax and Plague." Emerging Infections 5 Washington, D.C.: American Society for Microbiology Press, 2001.

ELECTRONIC:

World Health Organization. "Strengthening Global Preparedness for Defense against Infectious Disease Threats." Statement to the United States Senate Committee on Foreign Relations Hearing on The Threat of Bioterrorism and the Spread of Infectious Diseases. 5 September 2001. < http://www.who.int/emc/pdfs/Senate_hearing.pdf > (24 November 2002).

SEE ALSO

Anthrax, Terrorist Use as a Biological Weapon
Biological Warfare
USAMRIID (United States Army Medical Research Institute of Infectious Diseases
Vaccines