Regardless, highly possible plans can be devised could result in huge numbers of deaths that range into the thousands for chemical agents and the hundreds of thousands, or maybe millions, with biological ones6. Bioterrorists have successfully utilized agents ranging from the ones that rapidly cause death, such as nerve agents and cyanide, to those that impact hours after exposure, such as mustard gas and pulmonary agents. John Hopkins Center for Civilian Biodefense Studies compared potential biological agents to determine which maximum credible event would offer the greatest risk for a public health response. In this case, the "maximum credible event" is defined as an occurrence that could cause significant loss of life, as well as disruption, panic, and a total overwhelming of the civilian health-care resources. 7

To fit this definition of a maximum credible event, the CB must include some of the following properties: be highly lethal, easily produced in large quantities, stable in aerosol form for a large-scale attack, capable of wide dispersal, communicable from person to person, and untreatable. Anthrax and smallpox are the two agents with the greatest potential for mass casualties and civil disruption: They are both lethal -- if untreated before onset of serious symptoms, the death rate for anthrax is over 80%; 30% of unvaccinated patients infected with small pox would die. They are both stable aerosol forms and can be produced in large scale, have been developed as agents in state programs and would cause devastating psychological effect on target populations. The outbreak of both diseases would most likely be delayed, and vaccine availability of for either disease is limited. Gaining possession of the smallpox virus compared to other agents would be difficult, but could cause a public health catastrophe due to the disease's communicability: One case could lead to 10 to 20 others. Plague, like smallpox and anthrax, can decimate a population 8

Another way to find the best biological weapons is to look at what the former Soviet Union biological weapons experts considered the likely candidates. These agents included smallpox, plague, anthrax, botulinum toxin, equine encephalitis viruses, tularemia, Q fever, Marburg, melioidosis, and typhus. The criteria for listing these consisted of infectivity and toxicity, environmental stability, ease of large-scale production,...

The long-known diseases including anthrax, smallpox, and plague that can, and have, caused large outbreaks, continue to be the most probable. In addition, other agents, such as botulinum toxin, hemorrhagic fever viruses, and tularemia, have the potential to do the same. The U.S. public health systems must be prepared to detect, diagnose, and respond appropriately to these weapons. Just as important, they need to be ready to deal with the wide-scale human psychological terror this would cause.
End Notes

1. Mark G. Kortepeter and Gerald W. Parker, "Potential Biological Weapons Threats." Emerging Infectious Diseases Journal. July.August 1999, 523

2. "Report No. 2000/02: Chemical, Biological, Radiological and Nuclear (CBRN) Terrorism." Perspectives. http://www.csis-scrs.gc.ca/en/publications/perspectives/200002.asp18 December 1999

3. Frederick R. Sidell and David R. Franz. Introduction to chemical and biological agents. Medical aspects of chemical and biological warfare. (Washington, D.C.: Borden Institute, Walter Reed Army Medical Center, 1997), 4

4.Sidell and Franz, 4

5. Sidell and Franz, 5

6. "Report No. 2000/02"

7. Donald a. Henderson. "Smallpox as a biological weapon." Journal of the American Medical Association, 22, June 1999, 2128

8. Kortepeter and Parker, 525

9. Henderson, 2129