JY Choi, TW Hahn, HK Seo. IPVS. 2016
In South Korea, type 2 PRRSV has evolved continuously and has been subsequently characterized into at least four lineages, ever since the infection by this PRRSV genotype was first described in 1993. Recently, it was revealed that type 1 PRRSV to be not only widely distributed in South Korea but also divided into three genetic clusters based on phylogenetic analysis. Martínez-Lobo et al. demonstrated that pigs infected with the type 2 PRRSV strain showed more severe respiratory clinical signs and macro- and microscopic lung lesions than pigs inoculated with the type 1 PRRSV strain.
In Korea, since initially reported of type 1 PRRSV and some pathogenicity but highly pathogenic type 1 strain has not been reported in South Korea. Recently, relatively high mortality case with type 1 virus was identified.
This case report is the consequences of the vaccination of PRRS type 2 MLV against this highly pathogenic PRRS type 1.