Traditional surveillance systems have served public health well in detecting and responding to infectious disease outbreaks. While generally passive and dependent on laboratory confirmation, they have provided sufficient information to identify disease clusters. The world we live in has changed extensively in the past few decades, with the threat of bioterrorism, an imminent influenza pandemic, massive population movement, and emerging infectious diseases requiring surveillance systems that provide adequate lead time for optimal public health response. Traditional surveillance systems often operate with considerable delay, thus complementary surveillance systems are required to provide the necessary lead time. Syndromic surveillance systems may fulfil this role.^1,2

Syndromic surveillance uses clinical features that are discernable before diagnosis is confirmed or activities prompted by the onset of symptoms as an alert of changes in disease activity. Patient information may be acquired from multiple existing sources established for other purposes, including emergency department chief …