Abstract:

The 2 strains viruses were isolated by the SPF chicken embryo from chicken visceral tissues suspected of being infected with AIV H9 subtype in Luohe and Zhengzhou City in 2011. They were detected by HA, HI and RT-PCR method. The another 2 strains AIV H9 subtype viruses were isolated and identification in 2001. The test was carried out to aware of its cross immunogenicity protection. Inactivated vaccines were prepared with 2 strains of H9 AIV subtype isolated in 2001, and used to inoculate SPF chickens. The 4 strains were used to infect immunized chickens. The results indicated that the HI antibody titers against H9 subtype were significantly increased after inoculation, and there was a good cross protection force between H9 subtype isolated from different periods and locations. The study demonstrated that the inactivated vaccine prepared with the isolated strains in 2001 offered good protection against current pandemic H9 subtype.