ABSTRACT
Objective To study the genetic characteristics of avian influenza virus strain A/Zhejiang/16/2006 which was isolated from the case first reported in Zhejiang province.Methods Complete genome of A/Zhejiang/16/2006 including eight segments were sequenced and compared on the genetic homogeneity with sequences of the similar strains provided through domestic and overseas sources.Results There were 11 amino acids showing differences on HA between A/Zhejiang/16/2006 and the H5N1 isolates of neighboring countries,but these differences had not affected the stability of glycosylation sites.In the NA region,20 amino acids located in the 49th to 68th position were found absent in the isolates obtained after 1997.Eight segments of H5N1 isolates,circulating in the mainland of China in the recent years,formed a separate branch compared to the strains in neighboring countries and there was also obviously different from the strains isolated in Hong Kong and Guangzhou in 1996 and 1997.However,several Chinese strains were close to the Hong Kong strains isolated in 1997 but diffferent from the current strains in the phylogenetic tree.Conclusion The influenza virus strain A/Zhejiang/16/2006 formed a separate branch with the strains isolated in the mainland of China in the past years but it presented an obvious difference with the isolates from the neighboring countries.
ABSTRACT
<p><b>OBJECTIVE</b>To study the gene characterization of enterovirus 71 (EV71) virus strains isolated from clinical specimens of children with hand-foot-and-mouth disease (HFMD) in Zhejiang province.</p><p><b>METHODS</b>Virus were isolated from clinical samples including stool, throat swab and vesicle from patients with HFMD. The EV71 isolates were identified by microneutralization assay and reverse transcriptase PCR (RT-PCR) with specific primer pair for VP1 genes of EV71. Complete VP1 gene sequences (891 nucleotides) for recent 6 EV71 isolates were determined and compared with that of A, B, C genotype reference EV71 strains and 11 EV71 China isolates available from GeneBank by homogeneity and phylogenetic tree analyses.</p><p><b>RESULTS</b>9 strains of EV were isolated from 14 clinical specimens. Data from microneutralization and RT-PCR results indicated that all the strains belong to EV71. The nucleotide and amino acid homogeneity of these 6 Zhejiang strains with the representative isolates of A and B genotypes were 82.9%-85.5% and 94.9%-98.0% respectively; with the representative isolates of C were 89.2%-94.1% and 97.0%-99.0% respectively. There were 91.0%-92.2%, 90.2%-90.3%, 89.2%-89.5%, 96.7%-96.9% nucleotide, homology with representative strains of C1, C2, C3,C4 subgenotypes of EV71. The nucleotide homogeneity of these 6 EV71 isolated strains with 9 previously isolated Chinese strains appeared to be 93.8%-97.1%. These 6 EV71 isolated strains were within genotype C subgenogroup C4 in the phylogenetic tree.</p><p><b>CONCLUSION</b>The recently identified EV71 isolates in Zhejiang province belonged to subgenogroup C4.</p>