Characterization of H9N2 influenza viruses isolated from vaccinated flocks in an integrated broiler chicken operation in eastern China during a 5 year period (1998-2002).

摘要: In the current study, we characterized H9N2 influenza viruses isolated from vaccinated flocks in an integrated broiler chicken operation during a 5 year period (1998-2002). Phylogenetic analysis of 8 genes 11 representative showed that they all shared high similarity to first isolate, A/Chicken/Shanghai/F/1998 (Ck/SH/F/98), and clustered same lineages. Furthermore, had 9 nt deletion between positions 206 214 neuraminidase gene. These genetic characteristics strongly suggest these are descendants isolate. addition, our study also circulating this were evolving, as shown by antigenic variations manifested reactivity with polyclonal antisera monoclonal antibodies, haemagglutination erythrocytes different animals, amino acid differences haemagglutinin proteins, variation their ability replicate respiratory intestinal tract be transmitted aerosol. revealed internal some H5N1 duck origin together those virus RNP after 2001 more closely related Ck/SH/F/98-like viruses, indicating recent reassortment events two subtypes viruses. Continuous surveillance poultry waterfowl is critical for monitoring genesis emergence potentially pandemic strains region.