Biswas Dipankar, Dutta Mousumi, Sarmah Kimmi, Yadav Kaushal, Buragohain Manika, Sarma Kishore, Borkakoty Biswajyoti
Division of Virology, ICMR-Regional Medical Research Centre, N.E. Region, Dibrugarh, Assam, India.
Indian J Med Microbiol. 2019 Jan-Mar;37(1):42-49. doi: 10.4103/ijmm.IJMM_18_416.
Influenza A(H1N1)pdm09 virus, since its identification in April 2009, has continued to cause significant outbreaks of respiratory tract infections including pandemics in humans. In the course of its evolution, the virus has acquired many mutations with an ability to cause increased disease severity. A regular molecular surveillance of the virus is essential to mark the evolutionary changes that may cause a shift to the viral behavior.
Samples of Throat/Nasal swabs were collected from a total of 3715 influenza-like illness cases and screened by Real-time Reverse Transcription-Polymerase Chain Reaction for influenza viruses. Nucleotide sequence analysis was done to identify changes in antigenicity of the virus strains.
The present study describes the molecular characteristics of influenza A(H1N1)pdm09 viruses detected in Assam of Northeast India during 2009-2015. Influenza A viruses were detected in 11.4% (425/3715), of which influenza A(H1N1)pdm09 viruses were detected in 41.4% (176/425). The nucleotide sequencing of influenza A(H1N1)pdm09 viruses revealed a total of 17 and 22 amino acid substitutions in haemagglutinin (HA) and neuraminidase (NA) genes of the virus, respectively, compared to contemporary vaccine strain A/California/07/2009. The important mutations detected in HA genes of A/Assam(H1N1)pdm09 strains included E391K, K180Q and S202T. Mutation 'N248D' which has an ability to develop oseltamivir resistance was also detected in NA gene of A/Assam(H1N1)pdm09 strains.
Regular molecular surveillance of influenza A(H1N1)pdm09 is important to monitor the viral behavior in terms of increase virulence, drug resistance pattern and emergence of novel strains.
甲型H1N1pdm09流感病毒自2009年4月被发现以来，持续引发包括大流行在内的严重呼吸道感染疫情。在其演变过程中，该病毒获得了许多突变，导致疾病严重程度增加。对该病毒进行定期分子监测对于追踪可能导致病毒行为转变的进化变化至关重要。
从总共3715例流感样疾病病例中采集咽拭子/鼻拭子样本，通过实时逆转录聚合酶链反应对流感病毒进行筛查。进行核苷酸序列分析以确定病毒株抗原性的变化。
本研究描述了2009 - 2015年在印度东北部阿萨姆邦检测到的甲型H1N1pdm09流感病毒的分子特征。在3715例样本中，11.4%（425/3715）检测出甲型流感病毒，其中甲型H1N1pdm09流感病毒占41.4%（176/425）。与同期疫苗株A/California/07/2009相比，甲型H1N1pdm09流感病毒的核苷酸测序显示，其血凝素（HA）基因和神经氨酸酶（NA）基因分别共有17个和22个氨基酸替换。在A/Assam(H1N1)pdm09毒株的HA基因中检测到的重要突变包括E391K、K180Q和S202T。在A/Assam(H1N1)pdm09毒株的NA基因中还检测到具有产生对奥司他韦耐药性能力的突变“N248D”。
对甲型H1N1pdm09流感病毒进行定期分子监测对于从病毒毒力增加、耐药模式和新毒株出现等方面监测病毒行为非常重要。
