Zhejiang Provincial Centre for Disease Control and Prevention, Hangzhou, Zhejiang, People's Republic of China.
Epidemiol Infect. 2020 Feb 14;148:e296. doi: 10.1017/S0950268820000412.
Influenza is a major human respiratory pathogen. Due to the high levels of influenza-like illness (ILI) in Zhejiang, China, the control and prevention of influenza was challenging during the 2017-2018 season. To identify the clinical spectrum of illness related to influenza and characterise the circulating influenza virus strains during this period, the characteristics of ILI were studied. Viral sequencing and phylogenetic analyses were conducted to investigate the virus types, substitutions at the amino acid level and phylogenetic relationships between sequences. This study has shown that the 2017/18 influenza season was characterised by the co-circulation of influenza A (H1N1) pdm09, A (H3N2) and B viruses (both Yamagata and Victoria lineage). From week 36 of 2017 to week 12 of 2018, ILI cases accounted for 5.58% of the total number of outpatient and emergency patient visits at the surveillance sites. Several amino acid substitutions were detected. Vaccination mismatch may be a potential reason for the high percentage of ILI. Furthermore, it is likely that multiple viral introductions played a role in the endemic co-circulation of influenza in Zhejiang, China. More detailed information regarding the molecular epidemiology of influenza should be included in long-term influenza surveillance.
流感是一种主要的人类呼吸道病原体。由于中国浙江省的流感样疾病（ILI）水平较高，因此在 2017-2018 季节期间，流感的控制和预防具有挑战性。为了确定与流感相关疾病的临床谱，并描述该期间循环的流感病毒株，研究了 ILI 的特征。进行了病毒测序和系统发育分析，以调查病毒类型，氨基酸水平的取代以及序列之间的系统发育关系。本研究表明，2017/18 流感季节的特征是甲型流感（H1N1）pdm09、A（H3N2）和 B 病毒（均为 Yamagata 和 Victoria 谱系）的共同循环。从 2017 年第 36 周到 2018 年第 12 周，监测点的门诊和急诊患者就诊总数中，ILI 病例占 5.58％。检测到几个氨基酸取代。疫苗接种不匹配可能是 ILI 高比例的潜在原因。此外，在中国浙江流感地方性共同循环中，可能有多种病毒传入发挥了作用。应在长期流感监测中包含有关流感分子流行病学的更详细信息。
