Graphical representation of the locations of five IVI genes on the pathogenicity islands of S. suis serotype 2 strain P1/7. Based on a complete analysis of the SS2 reference strain P1/7 genomic sequence, W. Wei et al. predicted eight putative pathogenicity islands (PAIs). When we determined the locations of the 48 IVI genes identified by IVIAT, we found five IVI genes (sdh, ss-1955, srt, ss-1829, and ss-802) located in four pathogenicity islands in SS2 reference strain P1/7. The genomic map was published by W. Wei et al., 2006 (gray bars the third ring represent eight possible pathogenicity islands).