Mr. Chairman, distinguished Members, it is an honor to appear before you to address issues related to the technical aspects of biological warfare and biological terrorism. I am presently the Deputy Commander, U.S. Army Medical Research and Materiel Command, a subordinate command of the U.S. Army Medical Command. Until approximately one month ago, I commanded the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick, where I have served in various capacities for the past 11 years.
This Committee has asked that I address some very specific questions regarding biological warfare and terrorism, I have attempted to answer those questions below.
What is biological warfare...biological terrorism?
Biological warfare may be defined as the intentional use of microorganisms or toxins to produce death or disease in humans, animals or plants. Microorganisms include bacteria and viruses, which are also sometimes called replicating agents. Such agents can multiply within our bodies and produce disease or death after infection with a relatively small number of organisms. Biological toxins can be thought of as chemicals which are produced not by man, but by other living things --animal, plants or microorganisms--. Toxins do not make more of themselves, so the exposure dose itself is what causes illness. What distinguishes biological warfare from biological terrorism? The two differ in breadth --in the number of agents that can be used effectively-- and in the potential countermeasures available to deal with each. We have, generally, fewer tools and less information to protect citizens from terrorism than we have had to protect a defined military force from the classical biological warfare agents. I should note that, with regard to biological weapons, the threat to the force today may be more like the terrorist threat to our cities than the battlefield scenario for which we prepared during the cold war.
Why are we hearing so much about biological terrorism from the media now?
Before I discuss the more technical aspects of biological warfare and compare it to biological terrorism, I will note several factors that make these biological threats unique --as compared to chemical and nuclear weapons-- and explain why these threats are of special concern at this time in our history. First, facilities and equipment designed for legitimate applications can be used to produce biological agents; the facilities for Research and Development, scale-up and production of agents, especially on a terrorist scale, are widespread throughout the world to include the United States. This is frequently termed the "dual use" problem. Secondly, the collapse of the former Soviet Union and subsequent reduction in funding of its massive biological warfare infrastructure may have resulted in a vulnerability for recruitment by states trying to establish biological warfare programs. Finally, the incredible advances in biotechnology over the past 10 years --which hold great promise of changing our lives and those of our children for the good-- can potentially be used for evil as well. These factors make the important job of our intelligence community extremely difficult and complicate effective implementation of nonproliferation efforts.
How important is public understanding of these issues?
The biological terrorist --or even the biological hoaxer-- has another important factor on his side. We are afraid of what we don't understand. Superimpose, for a moment, the setting I have described above on a society influenced by the popular press and having a general lack of understanding of the technical aspects of this form of warfare; the result is a population primed for being jerked violently from complacency to panic with just a sensational news story or documentary. Education is a critically important and cost-effective part of the solution. Education of our doctors, our first responders, our media, our leaders and our citizens.
How do biological agents differ from chemical agents?
We all come in contact with dangerous chemicals daily. The gasoline we put in our automobiles is potentially extremely dangerous. It can burn us, it can damage our skin and it can make us sick if we inhale its vapor. Although chemical warfare agents work by completely different mechanisms and are much more toxic --most of them are volatile and active on the skin, like gasoline-- biological agents are neither volatile nor dermally active . In a liquid preparation, whether anthrax bacteria or botulinum toxin or Ebola virus, the biological agents will not move from an open container into the air without the addition of energy. We could spill any of these on the floor in this hall, clean it up with disinfectant, and go about our business. Not so for the chemical agents, which would vaporize and make us sick or kill us. Likewise, the majority of biological agents are not dermally active, so just getting them on intact skin will typically not cause disease. Fortunately, those two characteristics make the proliferator's job --or the bioterrorists job--more difficult. There are significant technical barriers that must be overcome to use biological agents effectively against our forces, and because of the factors I have mentioned above less formidable barriers to using them effectively against our society.
Other important differences between biological and chemical agents include the fact that 1) biological agents can be isolated from the environment, 2) some are contagious --therefore, disease could spread from exposed persons to a broader population-- 3) generally much smaller volumes of biological agent are required for a given target footprint and 4) the period between exposure and onset of clinical signs is typically much longer for biological than for chemical agents. The latter fact makes crisis management, and particularly triage of patients, after an overt biological attack much more difficult than for a chemical attack.
How may Biological Agents be disseminated?
Because of the physical characteristics of biological agents, the proliferator can probably expose a large target population efficiently only by generating what we call a respirable, or breathable, aerosol. A respirable aerosol is an airborne cloud of particles that can be inhaled and retained in our respiratory tracts. It would be difficult to produce mass casualties on a modern battlefield through contamination of food or water, even though the oral route is another way that biological agents can effectively enter our bodies. The terrorist who would produce hundreds of thousands of casualties with biological agents would need to develop an aerosol cloud, not just spray material into the air or let it escape from a container as was done with crude chemical agent in the Tokyo subway. Nevertheless, food and water contamination might be good enough for the terrorist, who may simply want to cause panic or make the nightly news.
What about the cold war biological threats?
Not all biological agents are created equal. If we examine the agent lists developed by proliferators during the cold war era, and even before, we see that most programs eventually focused on 10-15 agents. There is a reason the lists were so small. When one considers the hundreds of infectious agents and toxins, only a small subgroup has the physical and biological properties needed for a mass-casualty producing biological weapon. These characteristics include ease of production, infectivity or toxicity, stability --during processing, storage and in the environment-- and, of course, the ability to effectively cause illness or death in the exposed population. Anthrax comes out high on everyone's list because the spore form of the organism is so very stable. Some viruses require just a few organisms to infect and are so easy to grow to high concentrations that their relatively poor stability becomes less important. Two of the toxin families have been popular because of their extreme lethality or incapacitation effects. The point is that very few agents have the characteristics that make them good biological warfare, battlefield, mass-casualty weapons agents. However, terrorists don't have to deal with all the technical constraints intrinsic to the objectives of large national biological warfare programs.
Why are terrorist biological threats different?
To illustrate this point, we did a theoretical analysis of 395 toxins, using the available data on their toxicity and applying mathematical calculations that were validated in field tests during the US offensive program in the 1960s. We found that, based on toxicity alone, only 17 of the 395 toxins would be suitable for wide battlefield use. Seventy-three are toxic enough to use in an enclosed space such as the air handling system of a building or an aircraft carrier--or on a street corner during rush hour. The remaining 305 would be useful only as assassination weapons against individuals. Of the 17 toxic enough for battlefield use, all but a few would probably be useless because they are either unstable or too hard to produce in quantity. The same principles can be applied to bacteria and viruses; not all agents are "good enough" for the battlefield, but many more are good enough to get you on CNN. So, I hope you can see that the terrorist has a much broader --but not necessarily more deadly-- armamentarium of biological agents from which to choose.
Must we respond differently to the terrorist threat?
That multiplicity of potential terrorist agents makes the job of those charged with protecting our civilian population difficult. To protect a defined military force we can use prophylactic vaccines or drugs, we can place detectors on the battlefield and we can provide full-face respirators which our troops can don with adequate warning of an attack. After the attack, we can use diagnostic tools to identify the agent and possibly the exposed population and treat them with drugs or, in some cases, immunotherapy. We can decontaminate victims, although we believe decontamination is less critical following an aerosol biological attack than it might be following a chemical attack. It is important to note that, with the exception of the protective mask, the decontaminants and a subset of the detectors, the passive countermeasures must be designed for specific agents, or families of agents. Furthermore, in the case of a terrorist attack, we may not be able to use the vaccines, prophylactic drugs, detectors or the physical protection. Following an announced or at least an overt attack, we may only react to support an already exposed population - a population that, at the time, may look and feel no different than you and I do today. After a covert attack, local health care providers may be the first to notice that it has occurred; the outcome of such an attack may resemble a disease outbreak, compressed in time. It will likely be the relatively few scientists and clinicians in the DoD and HHS who conduct research with these organisms daily, who can provide the technical support to local, state and federal responders, and make the difference between normal life and illness or death for our citizens.
How difficult is it?
I think there is some good technical news in this story. I believe that an effective, mass-casualty producing attack on our citizens in this country would require either a fairly large, very technically competent, well funded terrorist program or state sponsorship. Although it will always be possible to obtain virulent organisms from the environment, the technical hurdles between the agar slant and a cloud covering many square miles of one of our cities are significant. One can quite easily produce a liquid preparation of a number of these agents, but liquids are difficult to disseminate effectively as aerosols. If the terrorist can acquire a good dried material, with a consistency like talcum powder, it would be easier to disseminate effectively. However, most organisms don't like to be dried and the process requires special equipment. And even with the high-quality dry material, weather and wind conditions make dissemination of the agent and the resultant footprint unpredictable.
Should we panic?
From my mostly medical research frame of reference, I believe the biological terrorist threat to our cities is real. I am concerned about state-sponsored terrorism, because with help, an individual or small group could truly produce mass casualties. But even following an effective attack, our established public health infrastructure within national, state and local governments could make an enormous difference. At the other end of the spectrum, spraying a diarrhea- causing bacterial preparation on a salad bar would be extremely easy to do and could cause discomfort to a few hundred --eg. the Rajneesh incident--. Nonetheless, I believe we can make a difference. In addition to our public health capabilities, a responsive research infrastructure with which to deal with the unknown, an effective intelligence program to reduce that which is unknown, solid law enforcement, moderation on the part of the media and especially education of our health-care providers and our citizens can make an enormous difference in the impact that the biological terrorist might have on our way of life. I believe such an integrated approach actually serves as a deterrent by increasing the risk to the terrorist and reducing the likelihood of a successful attack.
Again, I appreciate the opportunity to present this information before the Committee. I shall be happy to answer your questions.