3Bilodeau R,Dea S t Martineau G P,et al. Porcine reproductive andrespiratory syndrome in Quebec[ J]. Vet Rec, 1991,129: 102 -103.
4Christianson W T, Collins J E, Benfield D A, et al. Experimentalreproduction of swine infertility and respiratory syndrome in pregnantsows[J]. Am J Vet Res,1992,53(4) :485 -488.
5殷霖,刘景华.动物病毒学[M].北京:科学出版社,1997.
6ConzelmannK K,Visser N,Van Woensel P,et al. Molecular charac-terization of porcine reproductive and respiratory syndrome virus(PRRSV),a member of the Arterivirus group [ J ]. Virology,1993,193:329-339.
7Fang Y,Kim D Y,Ropp S,et al. Heterogeneity in of European -like porcine reproductive and respiratory syndrome viruses isolated inthe United States[J]. Virus Res,2004,100(2) :229 - 235.
8Mateu E,Diaz I, Darwich L,et al. Evolution of 0RF5 of Spanish por-cine reproductive and respiratory syndrome virus strains from 1991 to2005[ J] . Virus Res,2006,115(2) : 198 - 206.
