Using Digital Surveillance Tools for Near Real-Time Mapping of the Risk of International Infectious Disease Spread: Ebola as a Case Study

Sangeeta Bhatia; Britta Lassmann; Emily Cohn; Malwina Carrion; Moritz U.G. Kraemer; Mark Herringer; John Brownstein; Larry Madoff; Anne Cori; Pierre Nouvellet

HealthMap (www.healthmap.org) is another widely used tool for disease outbreak monitoring. In addition to ProMED alerts, HealthMap utilises online news aggregators, eyewitness reports and other formal and informal sources of information and allows for visualisation of alerts on a map [12] . The surveillance data collected by HealthMap has been incorporated into the Epidemic Intelligence from Open Sources (EIOS) surveillance system, developed by WHO. Both ProMED and HealthMap are used by key public health bodies, including the Centers for Disease Control and Prevention (CDC) and surveillance process. Compiling the data, conducting analyses, and generating reports that are easily understood and actionable are equally important. For instance, one of the ProMED outbreak analysts reported in March 2014 on the likely spread of Zika to the Americas [13] , well before the epidemic surfaced in South America in February 2015. However, lacking an easy to use and openly accessible tool to quantify and visualize the reported risk of disease spread, this report did not have any significant impact on public health resource allocation and decision making. While there has been a growing interest in using various internet data streams for epidemiological investigations [14, 15] and in using data from digital surveillance tools [16] , there is as yet a dearth of a framework that can automatically combine such data with other streams of information, analyse them in a statistically robust manner, and produce actionable reports, particularly in real time during an outbreak where such analyses would be most useful.