A Bacillus That Could Kill Us

Mechanisms of biological warfare are frequently based on the pathogenic potential of microorganisms. Because spore-forming bacteria such as Bacillus are so hardy, they have held a particular attraction to scientists as research subjects and, in one case, as the basis of a deadly bomb. Late in World War II, the mounting outrage over German bombings of London and the pressure for retaliation forced the British and American governments to collaborate on a powerful means of striking back. Given the knowledge that pneumonic anthrax was 100% fatal in a short time period, a highly secret council designed a bomb containing the spores of Bacillus anthracis. In the original plan, the detonation of these deadly projectiles over six German cities would have caused a shower of spores to be inhaled by humans and animals. Some estimates predicted that this could have wiped out the population over hundreds of square miles.

Late in the war, a plant in Indiana actually began to manufacture the bombs, but by this time, the war had started to wind down. How close the Allies came to dropping these bombs was not disclosed. During the Cold War, the U.S. Army’s Special Operations Division conducted a chilling experiment using Bacillus subtilis.

The plan was to simulate a possible method of germ warfare by releasing spore aerosols into the air of a crowded Washington, D.C. airport and bus terminal. Agents carried suitcases to spray the air while hundreds of unsuspecting people inhaled “large and acceptably uniform” doses, presumably with no ill effects. This study and several others like it were based on the disturbing assumption that B. subtilis is a harmless air contaminant. It should be clear even to beginning students that many species of bacteria are opportunists and are capable of causing disease, especially if present in large numbers. In fact, B. subtilis can cause lung and blood infections in people with weakened immunity. Although flawed, the test did fulfill its original purpose. It was determined that if smallpox virus had been used instead of B. subtilis, 300 people in 93 cities would have become infected and that similar exposures at terminals in several other large cities would have spread the disease rapidly to thousands of others. It was also shown that this contamination procedure could be accomplished without detection.

The potential threat from biological warfare is not only a concern of the past. Recent reports state that the governments of Iraq and North Korea have stockpiled huge arsenals of germ agents, including anthrax spores and botulinum toxin (another product of a gram-positive spore- former). There is a fear that these agents could be incorporated into bombs or missiles to be spread over long distances. International agencies are attempting to monitor and force elimination of the deadly agents. All U.S. military personnel are vaccinated to protect them against the use of biowarfare agents.