Syndromic surveillance for bioterrorism following the attacks on the World Trade Center--New York City, 2001.

Immediately after the September 11, 2001, terrorist attacks on the World Trade Center (WTC), the New York City Department of Health and Mental Hygiene (NYCDOHMH) was concerned about the possibility of a secondary attack with a biologic agent. Because NYCDOHMH lost communications as a result of the attacks, concern arose that this disruption would affect the ability to recognize a bioterrorist event. To address this concern, NYCDOHMH quickly implemented a syndromic surveillance system in hospital emergency departments (EDs) to identify a large-scale bioterrorist event and other health conditions related to the WTC attacks. This report describes the operational and maintenance aspects of conducting syndromic surveillance for bioterrorism (BT) and demonstrates the limitations of drop-in systems that rely on manual data collection. Health departments that are establishing early warning systems for BT should consider seeking routinely collected electronic data.