To demonstrate how event-based biosurveillance, using direct and indirect indications and warning (I&W) of disease, provides early warning and situational awareness of the emergence of infectious diseases that have the potential to cause social disruption and negatively impact public health infrastructure, trade, and the economy (1). Specifically, tracking of I&W during the 2011 enterohemorrhagic Escherichia coli (EHEC) O104:H4 outbreak in Germany and Europe was selected to illustrate this methodology.