Fig.

The 371 bp sequence of the N gene 5′-end was used for phylogenetic analysis within genotype I, which was conducted using MEGA version 3.1 (http://www.megasoftware.net/) (using the neighbour-joining algorithm) and PHYLIP version 3.63 (Seattle, WA, USA) (using the maximum parsimony method). The tree was estimated statistically by 1000 replicates of the bootstrap value and visualized by the TREEVIEW program (http://taxonomy.zoology.gla.ac.uk/rod/treeview.html). Genotype 3 MOKV was used as the outgroup and all sequence information is shown in the Table. The three major subgroups, A, B and C, correspond with published nomenclature [13]. Bold type, isolates of Hunan Province; italic type, isolates of other provinces; ▲, pig isolate HuNPN01; ◊, vaccine and challenge strains.