Shanghai Municipal Center for Disease Control and Prevention has implemented an active comprehensive surveillance project of acute respiratory infections in adults in Shanghai, including influenza like illness (ILI) and severe acute respiratory infection (SARI). By testing and identifying a variety of respiratory pathogens, it was found that influenza viruses were the main pathogens in 172 ILI cases in 2019. The positive rates of influenza A (H1N1) pdm09 virus, influenza A (H3N2) virus and influenza B virus Victoria lineage were 30.81%, 14.53% and 30.55%, respectively. The positive detection of influenza A (H1N1) pdm09 virus peaked in the first quarter. The positive rate of enterovirus/human rhinovirus was 6.40%, with a positive detection peak in the third quarter, while the positive rate of adenovirus was 4.65% with a positive detection peak in the second quarter of the year. Two human coronavirus (HCoV)-OC43 positive samples, 1 HCoV-HKU1 positive sample and 1 HCoV-NL63 positive sample were detected, respectively, and no HCoV-229E positive sample was detected. The detection rate of Staphylococcus aureus was 17.44%, and the detection rate of Klebsiellapneumoniae was 9.88%. Influenza viruses were also the main pathogens in 1 447 SARI cases. The positive rates of influenza A (H1N1) pdm09 virus, influenza A (H3N2) virus and influenza B virus Victoria lineage were 5.46%, 1.73% and 0.30%, respectively. The positive detection of influenza A (H1N1) pdm09 virus (17.50%) peaked in the first quarter. The total positive detection rate of enterovirus/human rhinovirus was 2.97%, the positive detection peaked in the first quarter. The positive rate of Mycoplasma pneumoniae was 3.25% and the positive rate of Legionella was 1.04%. 5 HCoV-229E positive samples, 10 HCoV-OC43 positive samples, 7 HCoV-HKU1 positive samples and 6 HCoV-NL63 positive samples were detected. Eight strains of Staphylococcus aureus, 4 strains of Pseudomonas aeruginosa and 3 strains of Klebsiella pneumoniae were detected after cultures. By implementing the active surveillance, we not only detected a case of human infection with avian influenza A(H7N9) virus in time, but also preliminary understood the pathogenic spectrum characteristics and seasonality of ILI and SARI in Shanghai. In recent years, the surveillance methods have been continuously improved and the number of sentinel hospitals has increased gradually. In particular, for the response to COVID-19, the Surveillance Information Reporting System of Acute Respiratory Infection based on HIS system has been promoted to cover the whole city, which might lay a foundation for the active surveillance and early warning of emerging infectious diseases in the future.

Objective:To analyze the epidemiological characteristics related to Norovirus-associated infectious diarrhea bud events in Shanghai, and to discuss the value of bud events surveillance, so as to help Norovirus-associated infectious diarrhea control, prevention and to improve the surveillance system on bud events.Methods:Data related to 142 Norovirus-associated infectious diarrhea bud events were gathered from 16 districts of Shanghai areas in 2018 and were analyzed.Results:There were 2 peaks, April and November for 142 Norovirus-associated infectious diarrhea bud events reported in 2018. 98.59 % (140/142) of the bud events occurred in schools and kindergartens. 80.28 % (114/142) of the bud events would involve 6-19 cases per each event. The median time duration between the onset date of the first case and the reporting date of the event was 2 days and the median event duration was 7 days. The bud event scale and regional incidence of bud events as well as the reporting timelines were influential factors on the duration of the bud events. Conclusions:Two peaks, spring and winter bud events of the Norovirus-associated infectious diarrhea were seen in Shanghai in 2018. Schools and kindergartens were to be prioritized locations for control and prevention of Norovirus-associated infectious diarrhea bud events. Surveillance system was proved to have contributed to the early detection, reporting and control of bud events.

Objective To analyze the antigenicity,genetic characteristics and variation of the hemagglutinin(HA) protein of influenza A(H1N1)pdm09 virus circulating in Shanghai during 2018-2019 influenza surveillance year.Methods Hemagglutinin inhibition test was performed to analyze the antigenicity of eighty-four influenza A(H1N1)pdm09 virus strains isolated in Shanghai from April 2018 to March 2019.Sixty-five influenza virus strains isolated from different districts of Shanghai were sequenced and analyzed.Results Clade 6B.1 H1N1 virus was the predominant strains circulating in Shanghai.A few epidemic strains belong to the 6B.2 branch.The similarities of clade 6B.1 nucleotide sequences compared with the vaccine strain A/Michigan/45/2015 were 97.1％-98.8％.The homology with the newly recommended vaccine strain A/Brisbane/02/2018 were 97.5％-99.4％.Mainly fifteen amino acids had mutated in the HA protein sequence,and three mutations,S91R,S181T and T202I were involved in three different epitopes which indicated that the antigenic drift had occurred in the influenza virus.Conclusions The majority of influenza A(H1 N 1)pdm09 subtype virus strains circulating in Shanghai were well matched with the vaccine strain A/Michigan/45/2015 recommended by WHO.It is necessary to continue strengthening the surveillance on influenza virus variation to improve the efficacy of influenza vaccines.