Even simple and imperfect bioterrorism events cause mass damage

In the case of biological warfare, the aim of which would be to kill or to incapacitate the largest possible number of enemy soldiers, the aggressor will consider measures to protect his own army and civilian population. In contrast, the aim of bioterrorism is to cause maximum disruption and to seed terror. This may be achieved by actual acts or by simply causing panic. While this does not necessarily imply actually harming more than a few people, many modern terrorist groups on the other hand do not seem to pay much attention to the safety, well being or even survival of their own followers. Terrorists will know that using highly infectious agents such as the smallpox virus for biological attacks might well mean their spread also to their own followers because they do not have smallpox vaccine or other preventative measures available.

How likely is a bioweapon attack and, more tightly focused, how real is the chance of such an attack by a terrorist group? It has to be taken into account that sophisticated microbiological and biochemical techniques are required to cultivate highly pathogenic biological agents and to make them suitable for use as bioweapons. Due to the high infectiousness of many potential bioweapon agents, all handling and manipulation would have to be done under Biosafety Level 3 (BSL 3) or BSL 4 conditions to protect the handlers [].

The CDC have developed a classification system for potential biological agents [, ]; Table  lists their definitions and gives some prominent examples for each of the three categories. Particularly categories B and C may be of interest to bioterrorists, due to the fact that some of these agents are not as infectious as those in category A and that dealing with them is, therefore, much easier. For example, multidrug-resistant Mycobacterium tuberculosis is relatively easy to cultivate at a relatively low biohazard level, and with its incubation period between weeks and years it would be very difficult for public health systems to realize that a large number of patients were the result of a bioweapon attack. However, the insidious course might compromise its terrorising effect. On the other hand, Marburg or Ebola viruses are, despite their fearsome reputation, rather unsuitable, not only because those involved in their propagation are likely to succumb to them before achieving their goals, but also because of their low ability to survive outside the human body. Efforts are underway to develop refined methods for assessing the suitability of biological agents as bioweapons [].

However, even such “impractical” agents might still be utilized, for it might be much more efficient to paralyze public health organs and healthcare systems through threats and alarms rather than doing much direct damage. Hoaxes were common in many countries in the aftermath of the 2001 anthrax attacks, with numerous letters allegedly containing B. anthracis spores causing considerable disruption and costs. Cleverly planned arrangements pretending biological attacks can indeed wreak havoc and can cause great expense, particularly because of a lack of systems for the rapid and accurate detection of real bioterrorism incidents and their reliable distinction from hoaxes [].