A reprint from American Scientist the magazine of Sigma Xi, The Scientific Research Society This reprint is provided for personal and noncommercial use. For any other use, please send a request to Permissions, American Scientist, P.O. Box 13975, Research Triangle Park, NC, 27709, U.S.A., or by electronic mail to [email protected]. ©Sigma Xi, The Scientific Research Society and other rightsholders The Growing Threat of Biological Weapons The terrorist threat is very real, and it’s about to get worse. Scientists should concern themselves before it’s too late Steven M. Block or half a century, America has par- cal development and use of biological um (Bacillus anthracis). Pasteur devel- F ticipated with the world’s nuclear weapons, as well as some recent trends oped the first animal vaccine against powers in an uneasy standoff of mutu- in their evolution and the prospects for anthrax, which, together with Lister’s ally assured destruction. Despite the containing their proliferation. ideas about antiseptic precautions, seemingly relentless proliferation of nu- helped turn the tide against outbreaks clear arms, there’s reason to hope that The Plague and Anthrax of the disease. some version of the current stalemate Biological warfare is not a new phe- Anthrax is only weakly communica- will continue to hold. Against this back- nomenon. The ancient Romans, and ble in humans and rarely causes dis- drop, terrorist factions and “nations of others before them, threw carrion into ease, unless the bacterium comes into concern” (the current government eu- wells to poison their adversaries’ contact with the bloodstream through a phemism for rogue states) have sought drinking water. In the 14th century the wound (causing cutaneous anthrax) or ways to leverage their chances. In the Tatars catapulted the bodies of bubonic- is ingested in contaminated meat (re- jargon of the day, they seek a means to plague victims over the city walls of sulting in intestinal anthrax). However, wage “asymmetric warfare” against a Kaffa, a Black Sea port that served as a Bacillus anthracis has the ability to form more powerful, nuclear-capable adver- gateway to the Silk Road trade route. resistant spores, which can remain vi- sary. Asymmetric warfare concentrates People inside the city soon came down able for over a hundred years if kept on the use of unconventional (and af- with the disease, suggesting that the desiccated and out of direct sunlight. fordable) weapons and tactics, ranging maneuver may have worked—but the Breathing in significant numbers of from traditional guerrilla fighting to the tactic may have exceeded the Tatars’ spores (typically estimated at about deployment of new weapons of mass operational goals. Some of the city’s in- 10,000) can lead to inhalation anthrax destruction. Ironically, the supremacy in habitants escaped in sailing ships, in humans, which was historically conventional weaponry established by which happened to be infested with called “woolsorter’s disease” because the U.S.—and demonstrated to lethal ef- rats, carrying fleas infected with the spores were prevalent in the contami- fect during the 1991 Gulf War—has causative agent of plague, the bacteri- nated wool of sheep in 19th-century made asymmetric warfare all the more um Yersinia pestis. The escaping ships England. Inhalation anthrax is a very attractive. Figuring prominently in the entered various Italian ports that sub- deadly disease in humans. Unless treat- arsenal of asymmetric warfare are both sequently served as foci for the spread ed with large doses of a penicillin-type biological and chemical weapons. Al- of the disease. Over the next three antibiotic within the first day or so of though it may be something of a mis- years, the bubonic plague—the Black exposure it has a mortality rate in ex- nomer to label most current forms of Death—raged northward, wiping out cess of 80 percent. This is to be contrast- these agents as “weapons of mass de- nearly a third of Western Europe. ed with smallpox, which has a mortali- struction,” their power is nevertheless It was not until the 19th century that ty rate of “only” around 30 percent. considerable. Worse still, it is now in- the microbial basis for infectious dis- Only some filoviruses, such as Ebola, creasing, and these weapons are emerg- ease was understood. One of the first which cause hemorrhagic fevers, have ing as a serious threat to peace in the illnesses to be explained by the new comparable rates of mortality. 21st century. Here I explore the histori- germ theory was anthrax, an infectious All of this suggests why Bacillus an- disease common to sheep and cattle. thracis became the agent of choice for Indeed, the primary architects of the most biological warfare programs. Steven M. Block is a professor of biological sciences and of applied physics at Stanford University, and a germ theory—Robert Koch, Louis Pas- Consider the properties of anthrax. It member of JASON. Address: Department of Biolog- teur and Joseph Lister—were instru- is convenient: Variants of the anthrax ical Sciences and Department of Applied Physics, mental in describing anthrax and its bacterium can be isolated worldwide Gilbert Hall, Stanford University, Stanford, CA containment. Koch was the first to iso- (although not all possess equal viru- 94305–5020. Internet: [email protected] late and describe the anthrax bacteri- lence), and great quantities of spores © 2001 Sigma Xi, The Scientific Research Society. Reproduction 28 American Scientist, Volume 89 with permission only. Contact [email protected]. Leif Skoogfors/Corbis Figure 1. Biohazard suits are the first line of defense against contamination for response teams entering a “hot zone”—the site of a biological- weapon release. A number of civil and military organizations—including the Department of Defense, the Centers for Disease Control and Prevention, the Federal Emergency Management Agency as well as local emergency medical services, fire and hazardous material experts and law enforcement specialists—now hold workshops and training sessions throughout the United States as part of a “Domestic Preparedness” program in case of a terrorist attack with a bioweapon. The challenge is to integrate these forces to mount an effective response under various attack scenarios. Here Marines prepare for a military exercise in Jacksonville, North Carolina. can be readily prepared from liquid edged sword, of course, since the vac- The World Wars cultures. It is robust: Once desiccated cine may be available to the target pop- The First World War saw one of the and stabilized, hardy spores have a ulation as well. For this reason alone, first attempts to use anthrax during long shelf life and are well suited to anthrax doesn’t quite qualify as the warfare, directed—ineffectively— weaponization in a device that can de- perfect bioweapon. against animal populations. Instead, liver a widespread aerosol. It is self-ter- There are certain other drawbacks to WWI became infamous for its intro- minating: Airborne spores remain in- anthrax as a weapon. The number of duction of poisonous mustard gas, fectious until they fall to the ground, spores that must be delivered to the which was used effectively against hu- where most become inactivated by lungs to produce the disease is quite mans. (By odd coincidence, WWI also sunlight. It is effective: After inhalation high compared with some other infec- overlapped with a deadly outbreak of the spores produce disease with a high tious agents—it has been estimated influenza, the Great Pandemic of 1918, mortality and morbidity. It can be con- that certain viruses and rickettsiae may which eventually killed more people tained: Anthrax is not very communi- communicate disease with just a single than the Great War itself.) International cable, thereby reducing the risk that it particle. Finally, for conventional an- revulsion at the horrors of WWI led to will spread beyond the intended tar- thrax, antibiotic treatment can be effec- the signing of the Geneva Protocol of get. Moreover, a well-established vac- tive if administered quickly. Even so, 1925, which went into force on Febru- cine exists that can prevent the onset of all the natural biowarfare agents, an- ary 8, 1928, with 29 participating na- of the disease, allowing it to be used thrax traditionally ranks near the top tions, including the U.S. The treaty safely by the aggressor. This is a two- of everyone’s short list. contained “A Protocol for the Prohibi- © 2001 Sigma Xi, The Scientific Research Society. Reproduction with permission only. Contact [email protected]. 2001 January–February 29 Sverdlovsk 1979 accidental release of anthrax from bioweapons facility Ping Fan, Manchuria 1936–45 Stalingrad 1942 Japanese Military Unit 731 Soviets infect German Panzer experiments on Chinese troops with tularemia Soviet Union 1972–92 Biopreparat (major Kaffa 1347 bioweapons program) Tatars catapult plague The Dalles 1984 victims over city walls salmonella release Tokyo 1990–95 by cult followers of Aum Shinrikyo makes several Baghwan Sri Rajneesh Iraq 1980s–1990s bioweapons program unsuccessful attempts to use bioweapons Figure 2. Historical incidents involving biological weapons span the globe and range from relatively modest events, such as salmonella poi- soning of salad bars in The Dalles, Oregon in 1984, to the notorious experiments by the Japanese military during the 1930s and 1940s, in which many thousands of Chinese were killed with infectious agents. Not all historical events are listed here. tion of the Use in War of Asphyxiating al occasions by dropping from air- A good deal of effort on both sides gas, and of Bacteriological Methods of planes laboratory-grown fleas fed on went into attacking the problem of Warfare.” infected rats. The Soviets may have weaponization. Biowarfare agents may Although the Geneva Protocol didn’t deliberately infected German Panzer be deadly, but they are also labile and expressly forbid the production and de- troops with tularemia during the Bat- difficult to deliver to the intended tar- velopment of biological weaponry, it tle of Stalingrad in 1942, by far the get.