ABSTRACT
Objective To investigate the characteristics of VP1 gene hypervariable region in hu-man enterovirus type 68(HEV68)strains isolated in China. Methods Nucleotide sequences of the VP1 gene in the Chinese strains and strains isolated in other countries were aligned by using Clustal W in the MEGA6 program. The phylogenetic trees were constructed by using Neighbor-Joining(NJ)method in the MEGA6 program. Sequence of the amino acids encoded by that region was analyzed by compared with that of the standard strain Fermon. Results A total of 80 strains of EV68 had been isolated in China by the end of 2015. Most of the mutations occurred in BC and DE loops. The mutation sites lied in the VP1 gene of Chi-nese isolates were at 83,89,91,94,96,97,98,102,109,139,141,142,143,144 and 147. Glycine was missing from most of the amino acid sequences encoded by the VP1 gene of Chinese strains. The phylo-genetic analysis indicated that 53 and 21 EV68 strains isolated in China belonged to B and C clades,respec-tively. Conclusion Compared with the standard strain Fermon,the Chinese strains changed a lot in BC-loop and DE-loop,which were associated with the antigenicity and virulence of EV68. The EV68 strains iso-lated in China belonged to B and C clades.
ABSTRACT
Objective To investigate the epidemic patterns and the characteristics of influenza in Chi-na through a Meta-analysis based on the studies published in domestic literatures.Methods Related articles published during 2005 to 2012 were screened out from domestic databases and analyzed through a Meta-analysis with Review Manager 5.0 software.Results Twenty-two articles covering 957 901 patients with influenza-like-illness (ILI) and 148 233 pathogen samples were screened out according to the inclusion criteria.No significant difference with the ILI diagnosis rate was found between subjects at age 0-4 years and those at age 15-59 years. Higher ILI diagnosis rates were observed in those two groups as compared with subjects elder than 60 years old. Most of the pathogen samples were carried by subjects aged 25-59 years.More influenza virus strains were isola-ted in 2009 as compared with those of the seven other years (OR=2.25, 95%CI=1.27-3.70).There was sta-tistical difference between the numbers of influenza A H1N1 and seasonal influenza A strains (OR=2.25, 95%CI=1.30-3.91) .Significant difference was also observed between the numbers of influenza A and influenza B strains (OR=4.05, 95%CI=2.53-6.47).Conclusion There was significant difference with the diagnosis rate between subjects aged 0-4 years and those aged≥60 years.More attention should be paid to people at high risk of infection (0-4 years old and≥60 years old) and those at 25-29 years with high mobility and social inter-course for the timely prevention and control of pandemic influenza.The detection rate of influenza virus strains was increased during the outbreak of novel influenza A H1N1 infection in 2009.After that outbreak, the detec-tion rate of novel influenza A H1N1 strains was 2.25 times the rate of seasonal influenza strains.The detection rate of influenza A was 4.05 times the rate of influenza B virus strains.Therefore, it is necessary to strengthen the surveillance for influenza A virus and other epidemic influenza virus strains.