A New Method of Differentiation Between a Biological Attack and Other Epidemics

The main obstacle in identifying a biological attack (BA), while preventing false alarms, epidemics of panic and unnecessary expenditures is the insufficient data on which to rely. Тhis new method of outbreak analysis is based on our original model of bioterrorism risk assessment. The intention was to develop a model of quick and accurate evaluation of an unusual epidemiologic event (UEE) that would save time, money, human and material resources and reduce confusion and panic. This UEE analysis is a subtle and detailed differentiation through assessment of BA feasibility in comparison with three other types of outbreak scenarios. There are two types of differences between these four scenarios: qualitative and quantitative. Qualitative and quantitative differences are defined with 23 and 10 indicators, respectively. Both types of indicators can have three different values: N/A, 0 or 1. We have carried out a feasibility analysis for subtle and detailed differentiation among four outbreak scenarios. As a tool for feasibility analysis we have introduced a “system of elimination”. System elimination is applied if one component contains all indicators scored with 0 or as N/A – the related scenario is then eliminated from further consideration. The system was applied to four UEEs: (1) an intentional attack by a deliberate use of a biological agent (Amerithrax), (2) a spontaneous outbreak of a new or re-emerging disease (“swine flu”), (3) a spontaneous outbreak by an accidental release of a pathogen (Sverdlovsk anthrax), and (4) a spontaneous natural outbreak of a known endemic disease that may mimic bioterrorism or biowarfare (Kosovo tularemia). It was found that “agent” was the most important and the most informative UEE component of the new scoring system. This system might be helpful in the analysis of unusual epidemic events and a quick differentiation between biological attacks and other epidemics.