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Objective@#Exploring the molecular characteristic of global and Shenzhen district H5N6 and H7N9 influenza viruses HA untranslated regions(UTRs).@*Methods@#Mega7.0 and DNAStar 7.1.0 were used to construct phylogenetic tree and nucleotide analysis.@*Results@#From 2014 to 2015, 3 strains of H5N6 influenza virus from Shenzhen were compared with the other H5NX influenza viruses, the nucleotide homology of HA-3’UTR was 77.4%-100%, which did not have obvious mutated sites. The nucleotide homology of H5N6-HA-5’UTR was 91.7%-100%, and the sites of 24 and 31 sites were mutated. From 2013 to 2014, 11 strains of H7N9 influenza virus from Shenzhen were compared with the other H7NX influenza viruses, the nucleotide homology of H7N9-HA-5’UTR was 76.8%-100%, which had multi-mutated sites on 2-6, 9, 10, 12 and 15-17 positions.@*Conclusions@#HA-UTR from human-infected H5N6 and H7N9 influenza viruses isolated in Shenzhen district has unique molecular characteristics, its conserved region has relatively high homology and the segment-specific region has genetic polymorphism.
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Objective To analyze neuraminidase(NA) inhibitor resistance of seasonal H1N1 influenza A viruses isolated in Shenzhen during 2008 to 2009. Methods The NA gene of these viruses were sequenced. Phylogenetic analysis of the sequences was performed with Mega3. 1 software. Results In 2008, most isolates of the seasonal H1 N1 virus were susceptible to neuraminidase inhibitors, but the H275Y mutation in the neuraminidase gene region associated with high-level oseltamivir resistance had been detected in 92.6% of the strains isolated in 2009. Furthermore, a strain with Q136K was found, which showed the resistance to Zanamivir. Conclusion In the light of emerging resistance, close monitoring and understanding of the nature and dynamics of resistance mutations in influenza virus should be a priority.
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Objective To study the prevalence and variation of influenza B viruses of Shenzhen. Methods Fifty strains influenza B viruses in Shenzhen from 1994 to 2006 were selected. HA1 gene were amplified by RT-PCR and sequenced. Phylogenetic analysis of HA1 was conducted by MEGA program. Results The influenza B viruses of Shenzhen were divided into Yamagata and Victoria lineage. The two lineages prevailed respectively in different years from 1994 to 2006. The variance of glycosylation site and some mutations of antigenic determinants were detected in the two lineages. Conclusion The viruses of Yamagata and Victoria lineage prevailed respectively in different years in Shenzhen but the mutation rates of the two lineages were slowly.
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Objective To analyze the genetic characteristics of H1N1 influenza viruses isolated in Shenzhen during 1995 to 2007. Methods The hemagglutinin(HA) gene of these viruses were sequenced. Phylogenetic analysis of the sequences was performed with Simmonic and Mega software. Results The H1N1 influenza viruses isolated in Shenzhen from 1995 to 2007 were divided into chide A, B and C. Some viruses from 2005 to 2006 clustered in the same group with the viruses of 2001. Furthermore, some of the vaccine strains recommended by WHO were found lagged behind the strains isolated in Shenzhen. Some mu-tations occurred on the antigenic sites as well as receptor-binding site(RBS). Except the viruses of 1995, the other viruses had deleted at the site 137. Conclusion Characterization of the HA gene revealed that most of the amino acid substitutions occurred on the antigenic sites and RBS. Furthermore, it was discovered that the mutations occurred on different antigenic regions in different years.