Molecular Epidemiologic Characteristics Of HA1 Gene Of Influenza Viruses In Jilin Province During 2005～2008

Objective To study the influenza activity and the characteristics of HA1 gene of influenza virus isolated in Jilin Province during 2005~2008 season. To elucidate the relationship between the influenza epidemic/outbreak and the variation of HA1 region of the virus. In order to provide the scientific basis of the prevention and treatment of influenza.Methods The data of ILI (Influenza-like illness) were collected by Influenza surveillance information system during October 2005 to March 2008, and analyzised with Excel software. The specimens which were pharynx swabs were collected from the ILI who visited the four sentinel hospitals by trained staff. The specimens were inoculated into MDCK cell flasks for influenza virus. The isolates were identified for influenza virus type and subtype by .To analyze the characteristics of HA1 gene of influenza isolated from Jilin Province in 2005-2008, and to elucidate the relationship between the influenza epidemic and the variation of HA1 region of the virus. The viruses were isolated and propagated by MDCK cell. RNAs were extracted and their HA1 genes were amplified by reverse transcription polymerase chain reaction (RT - PCR) . The purified PCR products were sequenced. Using the DNAStar software, the nucleotide and amino acid sequences on HA1 protein molecular of influenza virus were compared with that of influenza viruses which were epidemical in recent years or vaccine complement recommended by WHO.Results1,Through the epidemiological data show: 2005 ~ 2008, Jilin Province, the average hospital sentinel ILI% respectively 1.99%, 1.96%, 2.33% and 2.15%. ILI% highest values were 5.19% (in 2004 the first 50 weeks), 3.19% (in 2005 the first 48 weeks), 3.86% (2006 52 weeks) and 2.96 (2007 47 weeks), the overall level of smooth. Semi-annual monitoring results show that the peak of an influenza pandemic in Jilin Province usually appears in December each year, and a single peak. 2,January 2005 ~ December 2008 ,488 influenza strains were isolated from 3828clinical specimens from ILIs by MDCK (Madin-Darby canine kidney) cells, Of these, 149 (30.53%) influenza A (H1N1) viruses, and 146(29.92%) influenza A (H3N2) viruses, and 193(39.55%) B viruses.3,A 1-type influenza virus HA1 gene analysis showed that: 2005 ~ 2008, the nucleotide homology of influenza A virus isolated from Jilin Province is 95.5% ~ 99.9%. 05 ~ 2007 in Jilin Province A popular one with 07-08 years of influenza virus vaccine strains A/NewCaledonia/20/99 compared nucleotide homology of 96.0% ~ 98.0%; in 2008 a popular one virus and 08-09 years compared to the vaccine on behalf of A/Brisbane/59/07 nucleotide homology of 99.3% ~ 99.4%.4,A 3-type influenza virus HA1 gene analysis showed that: The pandemic strains of influenza H3N2 isolated in Jilin Province in 2007-2008 had 98.9-100% identity of nucleotides. Compared with A/wisconsin/67/05 vaccine strain recommended by WHO ,10-14 amino acid had changed, and there was one more glycosylation site at 122th site. The virus isolated in changchun city in November and December located in two different branches of the phylogenetic tree. The influenza strains of eight regions formed two clusters in the phylogenetic tree.5,B type influenza virus HA1 gene analysis showed that: The Yamagata-like and Victoria-like viruses co-circulated in 2005-2007 . Influenza B viruses in Jilin Province were different from the B/ Shanghai/ 361/ 2002 , Yamagata - like virus . 8 variant amino acids had changed in 2005 and 10 variant amino acids had changed in 2007. Compared with B/ Malysia / 2506/ 04 ,Victoria-like viruses ,The HA1 sequence data showed that the virus had replacement of 3 amino acids in 2007.6,Based on the 55 influenza virus HA1 gene sequencing and analysis of 2005 - 2008, based on the prevalence of influenza viruses in Jilin Province strength of prediction, forecasting the outcome of the basic line with the actual situation.Conclusion H1N1 influenza virus isolated in Jilin Province in 2008 has mutated compared ,2008-2009 vaccines A/Brisbane/59/07.2008-2009 vaccines have a better preventive effect. Compared with A/wisconsin/67/05, The viruses of influenza H3N2 in Jilin Province in 2007-2008 occurred evident antigenic drift in HAI region ;.in different times and regions the influenza pandemic strains had some difference. Compared with B/ Shanghai/ 361/ 2002, The Yamagata-like viruses in Jilin Province in 2005-2007 occurred evident antigenic drift in HAI region ;. The Victoria-like viruses were similar to the strain recommended B/ Malysia / 2506/ 04. Through two years of practice proved to be the HA gene of influenza virus variation of the monitoring, to determine the annual epidemic strains of influenza, early detection of mutant; timely assessment of the molecular level from the International Vaccine strains of Jilin recommend protective effect of the general population, in order to influenza epidemic prediction and early warning to provide an important basis.