For communicable diseases in particular, given the potential for initial exponential growth in the number of cases from a single diseased individual, it is crucial that a variety of methodologies, both prophylactic and reactive, be developed for limiting spread. These include vaccination, treatment, quarantine, movement restrictions, isolation and, in the case of nonhuman populations, culling. Because the potential for spread is determined by the number of secondary infections per primary infection, success in management can be achieved by a combination of reducing the infectious period and reducing transmission.

Studies must be done to develop decision rules and procedures for quarantine. These studies must be conducted with the goal of ultimately involving active participation of communities well before any event occurs. This will help reduce panic and irrational behavior in the case of an actual or suspected bioterrorism event. Quarantined communities must know where they will get medical care, antibiotics and vaccines, clean water, food, and mortuary service if the need arises.

A systems-level approach to dealing with bioterrorism threats, especially those involving communicable diseases, is needed. This approach must consider the integration of multiple modes of management, risk analysis in the face of inherent uncertainties concerning what agents will be introduced, and potential interactions among multiple biological agents. Such research is likely to rely heavily on the techniques of operations research, especially models that can be used for scenario development and training, for rapid response following detection of infected individuals, and for redesigning current systems (including possible patterns of movement) in order to make societies less susceptible to catastrophic outbreaks. Indeed, all of this argues for major development of modeling capabilities.

Uncertain Understanding of the Effects of Biological Weapons

Modeling the likely outcomes of different bioterrorism attacks is important for two reasons. It provides insight into the severity of the threat posed by the proliferation of biological weapons, and it allows one to estimate the effectiveness of different defensive responses (and hence the priority one should assign to each). Modeling efforts over the past decade, at least those publicly available, tend to emphasize worst-case scenarios—broadscale attacks involving millions of human casualties, if not fatalities. While such scenarios may be possible under the right circumstances, they probably are less likely than localized threats. In any case, a wider range of simulations is required to capture the range of possible outcomes. Here there is a major need for training; a critical mass of competent scientific expertise in epidemiological modeling has not to date been adequately supported. Such efforts should become major responsibilities of NIH, CDC, and DOD.

Constructing models may be easier, however, than supplying them with



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