The most urgent threat posed by microorganisms to national security is the development of an epidemic. An epidemic is an infection that, because of its ease of transmission from person to person (directly or via an intermediate) affects a large number of people within a very short period of time. The human toll and strain on the health care infrastructure due to naturally occurring epidemics such as inﬂuenzae are well known. In the past few decades, the emergence of diseases such as Acquired Immuno deﬁciency Syndrome (AIDS) and the re-emergence of tuberculosis has further strained the economies of even nations as wealthy as the United States. The specter of the deliberate use of microorganisms as a weapon—biological warfare—while historically ancient, has taken on new importance in recent years. In the United States, the terrorists attacks of September 11, 2001, were followed by a spate of incidents involving the deliberate release of spores of Bacillus anthracis, the bacterium that causes anthrax. While the consequences of these biological attacks were minimized due to a rapid response to track and contain the source, many people died from anthrax, and the incident illustrated the vulnerability of a population to infection. Scenarios envisioning the aerial dispersal of anthrax spores over a major urban center via a plane indicate that even 100 kilograms of spores carry the potential to kill hundreds of thousands or even millions of people within a few days.
The security threat posed by biological warfare is also ancient. Centuries ago, the decaying bodies of cattle that had died of infections were dumped into wells to poison the drinking water. Even deceased people provided the seed for the spread of infection to an enemy encampment, when the bodies of human victims of anthrax were catapulted over the walls of fortiﬁed communities. This military use of microorganisms became frighteningly reﬁned in the twentieth century. Both sides of the conﬂicts of World Wars I and II researched the development of weapons that would deliver anthrax spores.
During World War II Britain produced millions of anthrax ‘cakes’ that were to be parachuted into Germany. The intent was to decimate the population as well as the food chain. Other microorganisms, equally as ancient as anthrax, continue to be security threats because of their natural potential to cause massive disease outbreaks and because of their potential as biological weapons. One example is the disease known as plague, caused by the bacterium Yersinia pestis. Another example is smallpox, a disease that is caused by a virus. The tremendous infectivity of anthrax, plague, and smallpox have caused millions of deaths throughout history. This destructive potential did not escape the attention of governments, such as that of the former Soviet Union, which were interested in developing weapons. Indeed, the microorganisms that cause anthrax, plague, and smallpox have been included in the list of weapons that are strategic weapons.
Strategic weapons are those weapons that are capable of destroying entire populations. This puts these microorganisms on the same lethal level as nuclear weapons. The security threat posed by microorganisms took on an added urgency in the last two decades of the twentieth century, when their potential as a terrorist weapon was recognized. In contrast to bombs and other such munitions, the manufacture of lethal payloads of microorganisms does not require huge manufacturing facilities or large numbers of people. Moreover, the scientiﬁc and manufacturing expertise for the development of biological weapons is not beyond the typical microbiologist. Likewise, the transport of infectious microorganisms can be disguised. Microorganisms can be transported anywhere people can travel. A quantity of anthrax spores that would circulate through the ventilation system of an ofﬁce building can be contained in a vial carried in someone’s pocket. The ease by which microorganisms can be transported and released (i.e., by a small aircraft) is redeﬁning the nature of security. Methods that are successful in detecting missile silos and troop movements are useless against the deliberate use of microorganisms by a few individuals. The reﬁnement of genetic engineering technologies has made possible the tailoring of bacteria and viruses to make them more lethal. Microorganisms can normally be rapidly detected using antibodies that recognize a surface antigen. Redesigning a pathogen via genetic engineering so that the surface antigen is different and therefore no longer recognizable to the antibody thwarts the test.
A variety of contemporary examples have shown how vulnerable even developed countries are to the spread of infections. Examples of naturally-occurring infections are legionellosis in Australia, yellow fever and Creutzfeld-Jacob disease in Europe, and hantavirus pulmonary syndrome and cryptococcosis in North America. Modern technology has unexpectedly aided the spread of disease. The classic example is the development of resistance by bacteria to antibiotics. Antibiotics were considered to be ‘wonder drugs’ as recently as the 1960s. However, they have proved to only provide selective pressure for the development of bacteria that are even harder and more capable of causing disease. Many political scientists have warned of the security threat posed to the world in the twenty-ﬁrst century by epidemics of natural infections in underdeveloped and politically volatile countries. The decimation of the next generation of these countries could exacerbate feelings of hostility towards the wealthy nations of the West, putting many developed nations at risk.