Emergency department syndromic surveillance system for early detection of 5 syndromes: a pilot project in a reference teaching hospital in Genoa, Italy.

Early detection is fundamental for achieving effective control of infectious disease outbreaks. We described the development of a local chief complaint emergency department (ED)-based syndromic surveillance system to improve public health response in Genoa, Italy. The five syndromes under investigation by the syndromic surveillance system were influenza-like illness (ILI), low-respiratory tract illness (LRTI), not-haemorrhagic gastroenteritis, acute hepatitis, fever-with-rash (maculo-papular or vescicular) syndrome. Syndrome coding, data capture, transmission and processing, statistical analysis to assess indicators of disease activity and alert thresholds, and signal response were operatively described. Preliminary results on ILI syndromic surveillance showed that new system allowed the activation of the alert state with a specificity of 90.3% and a sensitivity of 72.9% in predicting epidemiological relevant events, such as > or = 10 accesses to ED for ILI in 3 days. The new syndromic surveillance system allowed to alert the public health institutions 2.5 days before than the local surveillance system based on sentinel physicians and paediatricians, permitting the early activation of the necessary measures for the containment and for burden reduction of the epidemic event. It is noteworthy that the syndromic surveillance epidemic cut-off was overcome once before and 4 times after influenza outbreak detected by sentinel-based surveillance system: all episodes were contemporary with Respiratory Syncytial Virus and Parainfluenza Virus circulation, as detected by regional reference laboratory.