The Growth and Variation of Symptoms of Influenza-like Illness: An Application of the Linear Growth Curve Model in Syndromic Surveillance in Rural China

To early detection of influenza outbreak in the rural China, we collected the 1-year data of ILI through the web-based syndromic surveillance system in rural China (ISSC). Linear growth curve model (LGM) can be used to predict growth trajectory of ILI over 7 days (one week) in each healthcare unit by the introduction of random effects. LGM is applicable in modeling the growth and variation of daily outpatient visits of ILI in rural healthcare units. The growth rate curves of ILI surveillance data might be useful for the early detection of influenza epidemic in rural China.