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ObjectiveTo analyze the genetic characteristics of the hemagglutinin （H） gene of measles virus （MeV） in Shanghai， 2001‒2018. MethodsNasopharyngeal swab specimens were collected from suspected measles cases reported in Shanghai from 2001 to 2018， and the isolation of measles virus was conducted with Vero/hSLAM cell line. RT-PCR amplification and sequencing were conducted after RNA extraction to analyze the genetic characteristics of the complete H gene. ResultsIn total， 5 665 nasopharyngeal swab samples were collected by suspected measles case surveillance from 2001 to 2018， and 1 394 measles virus strains were isolated. The homology of nucleotide acid and amino acid among 349 representative measles virus isolates was 87.4%‒100.0% and 85.1%‒100.0%， respectively. The homology of nucleotide acid and amino acid between representative measles virus isolates and China vaccine strain （S191） was 85.7%‒100.0% and 84.1%‒100.0%， respectively. All the sub-genotype H1a MeV isolates had an amino acid substitution （Ser240Asn）， which removed a predicted N-linked glycosylation site. ConclusionMost of the MeV isolates are sub-genotype H1a analyzed based on H gene， which are identical to those of the N gene. The predicted amino acid sequences of the H protein are relatively conserved at most of the functionally significant amino acid positions.
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Objective@#To analyze the phylogenetic characteristics of enterovirus 71 (EV71) in Xinjiang Production and Construction Corps from 2011 to 2016, providing pathogenic information for prevention and control of hand-foot-mouth disease (HFMD).@*Methods@#The EV71 positive strains were conducted for reverse transcription polymerase chain reactions (RT-PCR) amplification on entire VP1 coding region and sequencing was then performed and finally phylogcnetic tree was constructed among these strains and representative strains from GenBank using MEGA6.06.@*Results@#The homology of nucleotide and amino acid of the 37 EV71 strains were 87.3%-100.0% and 93.1%-100.0%, and belonged to EV71 C4a subgenotype, of 7 relatively independent small branches. Of the epidemic strains, compared with the representative strains, mutation occurred on 28 amino acid sites, the variation (Serine to Threonine, Alanine to Serine) happened on the 283 and 293 amino acid site in 9 strains.@*Conclusions@#The 37 EV71 strains in Xinjiang Production and Construction Corps from 2011 to 2016 belonged to EV71 C4a subgenotype, mutation occurred on 28 amino acid sites, and there is a common variation on the 283 and 293 amino acid site in 9 strains.
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Objective To investigate the mutation of hemagglutinin gene and amino acid variation of influenza B.Methods Influenza B virus was isolated from throat swab samples in sentinel surveillance of Yunnan province from 2009 to 2014.HA1 gene sequence analysis was applied to determine 12 randomly-selected strains of influenza B virus.The results were analyzed,MEGA software was used to do homology comparison and HA gene phylogenetic tree was established.Results Differences on the serotype and genotype identification of influenza strains were found and it might be caused by inadequate gene mutation accumulation.Amino acid variations were found in 3 important regions of antigenic determinants in HA1 protein:ring 120,ring 150 and ring 160.The amino acid variation of position 131 in ring 120 was N131K,and in position 137 was N137H.Two strains had P187S mutation in position 187.Conclusion There are some important variations in the hemagglutinin gene of influenza B strains in Yunnan Province,with some variations being the same as vaccine strains and some being not.