(1) the monitoring of the frequency of illnesses with a specified set of clinical features among a given population without regard to the specific diagnoses if any that are assigned to them by clinicians. (2) A system for early detection of outbreaks whereby health department staff assisted by automated acquisition of data routinely collected for other purposes and computer generation of statistical signals monitor disease indicators particularly those associated with possible terrorism-related biologic and chemical agents continually or at least daily to detect outbreaks earlier than would otherwise be possible with traditional public health methods.