Abstract:

Objective： To analyze the epidemicological characteristics of influenza in Yuxi city from 2010 to 2019， and to establish an autoregressive integrated moving average（ARIMA） model to predict the trend of influenza incidence. Methods： The data of influenza was analyzed by descriptive epidemiological methods， and the ARIMA model was established by SPSS 25.0 software. Results： A total of 9 925 influenza-like cases were detected in Yuxi influenza network laboratory， and 2 849 nucleic acid positive cases were detected， with a positive rate of 28.71%. The nucleic acid positive cases showed an upward trend year by year in general， with an average increment speed of 2.01%. Among influenza positive cases， the ratio of male to female was 1.25∶1， and children aged 5-14 accounted for the highest proportion （40.86%）. Influenza had a strong seasonality（concentration was 0.60）. The dominant influenza virus strains changed year by year. In 2010 and 2018， A/H1N1 pdm was dominant； in 2011 and 2012， B/Victoria was dominant； in 2013 and 2016， B/Yamagata was dominant； and in 2015 and 2017， A/H3N2 was dominant； in 2014， B/Yamagata and A/H1N1 pdm dominated， and in 2019， B/Victoria and A/H3N2 dominated. The best prediction model was ARIMA（1，0，0）（0，1，1）12， whose standardized BIC value was 5.873， Ljung-Box Q was 21.258， P was 0.169. The actual values of the prediction results were within the 95% confidence interval（95%CI） of the predicted value， and the average relative error was 10.14%. The model was used to predict a decreasing trend of influenza incidence from January to June in 2020. Conclusion： The influenza in Xuyi city has obvious seasonality and the nucleic acid positive cases show an upward trend year by year in general， and the dominant influenza strains change year by year. ARIMA（1，0，0）（0，1，1）12 model can effectively predict the trend of short-term influenza in Yuxi city.

Key words: font-family:", "> , influenzafont-family:宋体, ">, font-family:", "> concentrationfont-family:宋体, ">, font-family:", "> dynamic seriesfont-family:宋体, ">, font-family:", "> autoregerssive integrated moving average model