ESSENCE, the Electronic Surveillance System for the Early Notification of Community-Based Epidemics

ABSTRACT The Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE) is a secure web-based tool that enables health care practitioners to monitor health indicators of public health importance for detection and tracking of disease outbreaks, consequences of severe weather, and other events of concern. The ESSENCE concept began in an internally funded project at the Johns Hopkins University Applied Physics Laboratory (JHU/APL), advanced with funding from the State of Maryland, and broadened in 1999 as a collaboration with the Walter Reed Army Institute for Research. Versions of the system have been further developed by JHU/APL in multiple military and civilian programs for timely detection and tracking of health threats. Features of ESSENCE include spatial and temporal statistical alerting, custom querying, user-defined alert notifications, geographical mapping, remote data capture, and event communications. These features allow ESSENCE users to gather and organize the resulting wealth of information into a coherent view of population health status and communicate findings among users. The resulting broad utility, applicability and adaptability of this system led to adoption of ESSENCE by the Centers for Disease Control and Prevention (CDC), numerous state and local health departments, and the Department of Defense (DOD) both nationally and globally. With emerging high-consequence communicable diseases and other health conditions, the continued user-requirements-driven enhancements of ESSENCE demonstrate an adaptable disease surveillance capability focused on the everyday needs of public health. The challenge of a live system for widely distributed users with multiple different data sources and high throughput requirements has driven an novel, evolving architecture design.