The vicissitudes of influenza virus subtype H3 from 1999 to 2008 in Shaoguan city

ObjectiveTo investigate the vicissitudes of influenza virus subtype H3 in Shaoguan by the viriation of hemagglutinin HA1 domain of influenza A virus. MethodsRecovered the influenza virus strains by MDCK cell, Virion RNA were extracted and amplified by RT-PCR, The PCR were purified and test gene sequence, Edit the sequences by Bio-edit、DNA Start. Then compare and analyse the sequences using Clustal-W、Bio-edit、Treeview software. ResultsFour strains had tested, sequence analysis showed that the HA1 domain of these strains had 91.3%-93.8% homology with the vaccine strain A/Panama/2007/1999, 14 amino acids variation was observed in 5 antigenic deteminants, 6 amino acids variation in RBS, and one more glycosylation site at different site in each strain; Compared with the vaccine strain A/Fujian/411/2002,the homology was 90.2%-97.7%,18 amino acids variation was observed in 5 antigenic deteminants,10 amino acids variation was observed in RBS, and there was one more glycosylation site in strains A/SG/199/1999 and A/SG/y009/2008; Compared with the vaccine strain A/Wisconsin/67/2005, the homology was 88.3%-98.4%, 14 amino acids variation was observed in 5 antigenic deteminants,9 amino acids variation was observed in RBS, one more glycosylation site at different site in each strain; The mutation rate decrease gradually in these strains, the most two active amino acid site was in B and D antigenic determinant respectively. ConclusionThere were three times antigen drift of influenza virus subtype (H3) were occurred in Shaoguan between 1999-2008, they were in 1999, 2002 or 2003, 2007 respectively; every variation had 3-4 years intervals. The trend of the antigen drift of influenza virus subtype(H3) strengthen from the situation of 2008.