Objective To characterize the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) of influenza B viruses isolated in Jiangsu province,2011.Methods Thirteen strains of influenza B virus in different areas and epidemic period in Jiangsu province,2011 were selected for whole-genome sequencing,and analysis of molecule epidemic characteristics for HA and NA was carried out by bioinformatics method.Results Of the 13 randomly selected influeuza B strains,10 strains were assorted to Victoria lineage strains with NA genes from Yamagata lineage,and 3 strains belong to Yamagata lineage.Compared nucleotide and amino acid sequences of HA and NA genes with their vaccine strains respectiuely,196/197 glycosylation site appeared on HA1 gene in Yamagata/Victoria isolates virus.Conclusion Both B/Victoria and B/Yamagata lineage viruses co-circulated in Jiangsu province,and reassortant virus of Victoria lineage were predominant virus.

Currently,three predominant subtypes of influenza virus are prevalent in pig populations worldwide:H1N1,H3N2,and H1N2.European avian-like H1N1 viruses,which were initially detected in European pig populations in 1979,have been circulating in pigs in eastern China since 2007.In this study,six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China.Based on whole genome sequencing,molecular characteristics of two isolates were determined.Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations,especially similar to those found in China.Four potential glycosylation sites were observed at positions 13,26,198,277 in the HA1 proteins of the two isolates.Due to the presence of a stop codon at codon 12,the isolates contained truncated PB1-F2 proteins.In this study,the isolates contained 591Q,627E and 701N in the polymerase subunit PB2,which had been shown to be determinants of virulence and host adaptation.The isolates also had a D rather than E at position 92 of the NS1,a marker of mammalian adaptation.Both isolates contained the GPKV motif at the PDZ ligand domain of the 3' end of the NS1,a characteristic marker of the European avian-like swine viruses since about 1999,which is distinct from those of avian,human and classical swine viruses.The M2 proteins of the isolates have the mutation (S31N),a characteristic marker of the European avian-like swine viruses since about 1987,which may confer resistance to amantadine and rimantadine antivirals.Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs,and raise more concerns about the occurrence of cross-species transmission events.

ObjectiveTo investigate norovirus infection status and indentify its epidemiological characteristics and genotype distribution in infantile viral diarrhea in Jiangsu.MethodsFour hundred and ninety-eight fecal specimens of infantile virus diarrhea cases were collected from Suzhou Children's hospital and Nanjing Children's hospital in 2010.Norovirus genegroup were detected by real-time RT-PCR,and genetype were determined by sequence analysis.Results Among all fecal specimens,2 (0.4％) cases were positive for norovirus G Ⅰ,and 190 (38％) cases for G Ⅱ.Nucleotide sequence analysis revealed that in the 2 samples for G Ⅰ,one strain was G Ⅰ 1 and another was G Ⅰ 3.Twenty-one strains were belonged to G Ⅱ 4 and 2 strains were G Ⅱ 3 in the 23 samples for G Ⅱ.ConclusionAs one of the most important pathogens causing infantile viral diarrhea in Jiangsu province,subtype G Ⅱ 4 was the main epidemic strain of norovirus,meanwhile other genotypes also existed.

BACKGROUNDPB1-F2 protein has been proven to increase the pathogenicity of influenza A virus (IAV) strains in primary infection and in secondary bacterial infection. It can also regulate the activity of viral polymerase. However, it was shown in another retrospective study that a portion of IAVs do not express full-length PB1-F2 protein during virus development; different kinds of stop codons cause exits in the open reading frames and form PB1-F2 gene products with the corresponding genotypes. Truncated PB1-F2 in human H3N2 IAVs has long been detected in North America but its evolution in China is still unclear.

METHODSInfluenza-like illnesses (ILIs) from the whole of Jiangsu Province were collected and inspected to determine the type and subtype of the viruses. A portion of isolates collected in the epidemic period were selected as samples for later whole-genome sequencing, and the exact sequences were determined and analyzed.

RESULTSH3N2 influenza virus was one of the epidemical strains which had been prevalent during 2009-2010, in Jiangsu. Five H3N2 isolates with truncated PB1-F2 protein (25aa) were detected in influenza samples from Nanjing and Xuzhou, while seven similar H3N2 isolates were also reported in Niigata, Japan.

CONCLUSIONThis emergence indicates the possibility that there has been transmission of the H3N2 virus between the two countries.

China ; epidemiology ; Humans ; Influenza A Virus, H3N2 Subtype ; genetics ; metabolism ; Influenza, Human ; virology ; Viral Proteins ; chemistry ; genetics ; metabolism