Molecular And Pathogenicity Analysis Of H5N1Avian Influenza Viruses In China In2010

Related system researches were studied on twelve H5N1subtype avian influenza viruses (AIVs) which isolated from poultry in a routing survey at a live poultry market in South China, in order to understand extensively characterization of H5N1AIVs. Antigenic analysis through adopted cross HA-HI test, the results indicated that the reaction between different types of antiserum and isolates had obvious diversities; the newly emerged Clade2.3.2C and Clade2.3.4B had some diversities to the antisera generated from the current H5N1(Re-4and Re-5) vaccine The viruses which was diluted finitely were inoculated chicken embryo to purify, then extracted viral RNA, through reverse transcription, polymerase chain reaction (PCR), viral genome DNA of amplification, the viral genome were sequenced, phylogenetic tree were drawed. Sequencing analysis results showed that the nucleotide homology of genomic were above95%among the tweleve isolates and highly similar to A/crested-grebe/Qinghai/1/2009(H5N1) and A/black-crowned night heron/Hong Kong/659/2008(H5N1); PB1gene of CK/JS/S1006/2010had highly similar to H9N2isolates which derived from wild birds in China recently, so the source of these genes was some complicated which was belong to recombinant virus. The cleavage site residues of HA protein in the isolates were341RRRKR345or341RRRRKR346which proved to be the highly pathogenic molecular characteristic of AIVs. The mortalities of twelve H5N1AIVs in four week-old SPF ducks were different via intranasal inoculation of105EID50in the experimental set,, the results indicated that high, medium, low pathogenicity of duck was divided into three types, all isolates were able to cause systemic infection in duck and shed the virus through both larynx and cloaca. The pathogenicity of twelve H5N1AIVs in six week-old BALB/c mice were different via simulated natural infection way and intranasal inoculation of101EID50～106EID50, the results indicated that isolates were able to replicate efficiently in mouse lung with high virus titers and the pathogencity of mice were divided into high and medium type, most of the isolates were highly pathogenic to mice mammal model.