4Chen J,Liu T,Zhu C G, et al. Genetic variation of Chi- nese PRRSV strains based on ORF5 sequence. Bioehem Genet. 2006,44(9 - 10) :421-431.
5Dfaz I, Darwich L, Pappaterra G, et al. Immune responses of pigs after experimental infection with a European strain of porcine reproductive and respiratory syndrome virus. J Gen Virol. 2005, 86 (7) : 1943-1951.
6Oliphant T, Nybakken G E, Engle M, et al. Antibody Rec- ognition and Neutralization Determinants on Domains I and Ⅱ of West Nile Virus Envelope Protein. J Gen Virol. 2006, 80 (24) : 12149-12159.
9Lopez 0 J,Oliveira M F, Garcia E A, et al. Protection against porcine reproductive and respiratory syndrome virus (PRRSV) infection through passive transfer of PRRSV-neutralizing antibodies is dose dependent. Clin Vaccine Immun. 2007, 1 4(3) :269-275.
10Li Y, Wang X, Bo K,et al. Emergence of a highly pathogenic porcine reproductive and respiratory syndrome virus in the Mid -Eastern region of China. Vet J. 2007, 17 (4) : 577-584.
