Biological warfare training: infectious disease outbreak differentiation criteria.

The threat of biological terrorism and warfare may increase as the availability of weaponizable agents increases, the relative production costs of these agents decrease, and, most importantly, there exist terrorist groups willing to use them. Therefore, an important consideration during the current period of heightened surveillance for emerging infectious diseases is the ability to differentiate between natural and intentional outbreaks. Certain attributes of a disease outbreak, although perhaps not pathognomonic for a biological attack when considered singly, may combine to provide convincing evidence of intentional causation. These potentially differentiating criteria include proportion of combatants at risk, temporal patterns of illness onset, number of cases, clinical presentation, strain/variant, economic impact, geographic location, morbidity/mortality, antimicrobial resistance patterns, seasonal distribution, zoonotic potential, residual infectivity/toxicity, prevention/therapeutic potential, route of exposure, weather/climate conditions, incubation period, and concurrence with belligerent activities of potential adversaries.