Concerns about bioterrorism led me to organize a Columbia University seminar course on microbiology and bioterrorism, which ultimately led to a book, Agents of Bioterrorism, the first draft of which was produced by the seminar participants.
Pathogens considered to be major biothreats are the central topic. They are examined from the standpoint of their biology and the steps that might be taken to defend against them. The information complements what is usually presented in a microbiology text.
Each chapter considers a particular pathogen -- anthrax, encephalitis, botulism, ebola, tularemia, salmonella, plague, smallpox, influenza and severe acute respiratory syndrome (SARS) -- from the standpoint of its history, molecular biology, pathology, clinical presentation, diagnosis, weaponization and defenses. The book contains four appendices covering rapid drug discovery, different strategies for making vaccines, protection of the population in a bioterror attack, and sources of information on bioterrorism. A glossary is also included.
Thus far, terrorists of the 20 th and 21 st centuries have tended to use explosives both because they have been very successful and require the minimum of skills to employ. However, fears are mounting that terrorists will turn to biological agents because such weapons are easier to hide, cheaper and far more devastating than explosives.
Bioterrorism remains in many ways a taboo subject, as it disturbs many people to the point where they would rather ignore it. Interestingly, the term bioterrorism has yet to appear in most dictionaries although it frequently appears in American newspapers.
Yet there is a long history of the military use of biological weapons. The sixth-century (B.C.E.) Assyrians are believed to have poisoned water sources of their enemies with a toxic fungus. In the 14 th century, Tatar armies are said to have thrown the corpses of plague victims over their enemies' walls in an effort to start epidemics. In more recent times (1984), in Dulles, Oregon, 10 area restaurants were linked to a series of salmonella outbreaks that were traced to a cult that intentionally contaminated the food supply. In the year 2001, terrorists sent mail containing deadly anthrax spores to several U.S. cities. Although only a few deaths resulted, the incident was terrifying to a much larger number, not only of postal employees but of other kinds of workers. Attempts to discover the culprits are still active.
But while bioterrorism is as old as recorded history, what distinguishes today's bioterrorism are the scientific advances that have been made in our understanding of how pathogens produce their toxins and how the toxin kills or injures the infected host. This information could conceivably be useful to the terrorists to make the toxin more potent or to the antiterrorists to produce antitoxins or procedures for protecting ourselves against pathogens.
The Centers for Disease Control and Prevention (CDC) is the agency within the U.S. Department of Health and Human Services whose job it is to protect American citizens from infectious diseases. They have ranked biological agents based on the dangers they pose and the likelihood that they will be used as agents of bioterrorism.
Category A agents are easily disseminated and /or highly infectious and are characterized by high mortality rates. Because of their speed of action, they are likely to strain the public health infrastructure if released. In addition, many are untreatable or difficult to treat -- and hence could cause public panic.
Category B agents are considered lower in priority because of their lower mortality rates and the ease with which they can be treated.
Category C agents are emerging pathogens considered to have a potential for weaponization due to their potentially high morbidity and mortality rates as well as their availability.
Classification schemes may change as we learn how to cope with existing pathogens, or as terrorists learn how to make available pathogens more deadly. For example, Vibrio cholera, which is now classified as a Category B agent, would once have been considered a Category A agent until it was learned that simple hydration therapy lowers its lethality from 50 percent to 1 percent. On the other hand, anthrax might have been classified as a Category B agent until procedures for producing powdered spores of anthrax gave it greater stability and potency.
While bioterrorism has not been used on a grand scale so far, it seems reasonable that we should develop procedures for protecting ourselves from some pathogens that are most likely to be used. The most commonly used safeguards are vaccines, antibiotics and antimetabolites.
Weaponization, the processing of a pathogen to make it even more potent, is another important, as well as controversial, topic. Those who oppose its discussion feel that terrorists could misuse this knowledge. Those who favor its being discussed feel that without this information scientists who are intent on developing biodefense systems will be severely impaired.
This topic is currently being hotly debated. In the view of the book's contributors, the subject should be open for discussion because the good guys far outnumber the bad guys, and in general they are also smarter.
Finally, let me say that my principal motive for publishing a text on this topic was to provide knowledge to others so that they would have some idea of how to protect themselves. We can't simply rely on government measures. Experience shows that the government is more likely to react than to initiate defensive measures. For example, it seems unlikely that respirators will be made available to the general public until after we have suffered a major attack using an aerosolized pathogen. A wise precaution would be to procure one or two respirators with a good filtration system. Most pathogens form aerosols whose damaging effects would be greatly lowered by wearing one at the time of attack.
Geoffrey Zubay is a professor of biology at Columbia. He recently authored a volume, Agents of Bioterrorism: Pathogens and Their Weaponization ( Columbia University Press, 2005). Professor Zubay has published more than 150 research papers and several books, including Biochemistry, Genetics and Origins of Life on the Earth and in the Cosmos . In 1984 he received the Selman Waksman Award for Outstanding Contributions to Microbiology.