1Prideto C,Alvarez E,Martinez-Lobo F J.Similarity of Eu- rope an porcine reproductive and respiratory syndrome virus strains to vaccine strain is not necessarily pre- dictive of the degree of protective immunity conferred [J].Vet J,2008,175(3):356-363.
6Plana-Duran J,Bastons M,Urniza A,et al.Efficacy of inac- tivated vaccine for preventionof reproductive failure induced by porcine reproductive and respi syndrome virus [J].Vet Microbiol,1997,55(1-4):361-370.
7Nielsen J,Botner A.Hematological and immunological pa- rameters of 41/2-month old pigs infected with PRRS virus [J].Vet Microbiol,1997,55(1-4):289-94.
8Nielsen TL?Nielsen J.Have P,et al.Examination of virus shedding in semen from vaccinated and from previously infected boars after experimental challenge with porcine reproductive and respiratory syndrome virus[J].Vet Mi- crobiol,1997,54(2):101-112.
9Schagemann G,Bohnet W,Kunstyr I,et al.Host specificity of cloned Spironucleus muris in laboratory rodents[J].Lab Anim,1990,24(3):234-239.
10Botner A,Nielsen J,Bille-Hansen V,et al.Isolation of porcine reproductive and respiratory syndrome(PRRS)virus in a Danish swine herd and experimental infection of pregnant gilts with the virus[J].Vet Microbiol,1994,40(3-4):351-360.