Figure 6. Lung lesions in pigs infected with PRRSV A2MC2-P9, A2MC2-P75, A2MC2-P90 and MLV at 14 days post-infection.

Four pigs from each group were necropsied. Mock-infected pigs (PBS) were included as controls. (A) Average macroscopic lung lesion scores. Error bars represent standard errors of the scores among the four pigs in each group. A2: A2MC2. (B) Average microscopic lung lesion scores. Significant differences between the group of A2MC2-P9-infected pigs and each of the rest groups are denoted by “**”, which indicates P < 0.01.