The project established the importance of HL7 message routers (also known as integration engines) for public health surveillance. HL7 message routers are a mature, highly prevalent technology in health care. We demonstrated that free-text triage chief complaints can be obtained in real time from most U.S. hospitals through message routers and that these data represent early syndromal information about disease. Many other clinical data of value to public health are transmitted using the HL7 standard (e.g., orders for diagnostic tests, especially microbiology tests, reports of chest radiographs, medications, and test results) and can be integrated into RODS or other surveillance systems capable of receiving HL7 messages.