Influenza Group, ICMR-National Institute of Virology, Pune, India.
Department of Health Research, Ministry of Health & Family Welfare, Government of India, New Delhi, India.
Indian J Med Res. 2019 Jun;149(6):783-789. doi: 10.4103/ijmr.IJMR_925_18.
BACKGROUND & OBJECTIVES: Influenza virological surveillance is an essential tool for the early detection of novel genetic variants of epidemiologic and clinical significance. This study was aimed to genetically characterize A(H1N1)pdm09 virus circulating in 2017 and to compare it with the global data.
The regional/State Viral Research and Diagnostic Laboratories (VRDLs) provided influenza diagnosis for referred clinical samples and shared influenza A(H1N1)pdm09 positives with the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune, India, for hemagglutinin (HA) gene phylogenetic analysis. Sites at Manipal, Jaipur and Dibrugarh performed the sequencing and shared the sequence data for analysis. The antiviral susceptibility of influenza viruses was assessed for known molecular marker H275Y at the ICMR-NIV, Pune.
All the eight VRDLs had well-established influenza diagnostic facilities and showed increased activity of influenza A(H1N1)pdm09 during 2017. Phylogenetic analysis showed that the viruses from the different regions of the country were similar to A/Michigan/45/2015 strain which was the 2017-2018 recommended vaccine strain and were clustered with the globally circulating clade 6B.1 with signature mutations S84N, S162N and I216T. The clade 6B.1 showed further subgrouping with additional mutations S74R, S164T and I295V; however, there was no significant association between the presence of these mutations and severity of disease due to influenza. All the study viruses were sensitive to oseltamivir.
INTERPRETATION & CONCLUSIONS: During the study period, all the study sites reported globally circulating A/Michigan/45/2015 vaccine strain of influenza A(H1N1)pdm09 viruses and remained sensitive to oseltamivir. Further genetic and antigenic characterization of influenza viruses is recommended to address public health concerns.
流感病毒学监测是早期发现具有流行病学和临床意义的新型遗传变异的重要工具。本研究旨在对 2017 年流行的 A(H1N1)pdm09 病毒进行基因特征分析，并与全球数据进行比较。
地区/邦病毒研究和诊断实验室（VRDL）为送检临床样本提供流感诊断，并将 A(H1N1)pdm09 阳性样本与印度医学研究理事会-国家病毒学研究所（ICMR-NIV）共享，供血凝素（HA）基因系统发育分析使用。曼尼帕尔、斋浦尔和第布如加赫的实验室负责测序，并共享序列数据进行分析。在浦那的 ICMR-NIV 评估了流感病毒对已知分子标志物 H275Y 的抗病毒敏感性。
所有 8 个 VRDL 都有完善的流感诊断设施，并在 2017 年显示出 A(H1N1)pdm09 活跃度增加。系统发育分析显示，来自该国不同地区的病毒与 2017-2018 年推荐疫苗株 A/Michigan/45/2015 相似，属于全球流行的 6B.1 分支，具有 S84N、S162N 和 I216T 特征性突变。6B.1 分支进一步细分为具有额外突变 S74R、S164T 和 I295V 的亚组；然而，这些突变的存在与流感引起的疾病严重程度之间没有显著关联。所有研究病毒对奥司他韦均敏感。
在研究期间，所有研究地点均报告了具有全球流行的 A/Michigan/45/2015 疫苗株的流感 A(H1N1)pdm09 病毒，且对奥司他韦保持敏感。建议进一步对流感病毒进行遗传和抗原特征分析，以解决公共卫生问题。
