Correlation between AUC (area under the curve) viremia and ADWG, AUC viremia and PRRSV viral loads in the serum and lungs, and ADWG. A The correlation (Spearman’s, r) between AUC viremia (0–21 dpc) and ADWG (until 28 dpc) was tested in the pigs after infection with JA142. B The viral loads in the serum samples collected from all pigs were quantified (using qRT-PCR) at 0 (before challenge), 3, 7, 14, 21 and 28 dpc. The viral loads are expressed as TCID50 equivalent/mL (log10). C ADWG in all pigs was calculated at every week up to 28 dpc and expressed as kg/day. D The lungs pathology (gross and microscopic lesions), and residual virus titers in the lung tissues collected from pigs at 28 dpc were measured using a microtitration infectivity assay performed in MARC-145 cells and presented as TCID50/mL (log10). The error bars represent the standard error of the mean (SEM). Asterisks indicate significant differences in each parameter among the genotypes (*p < 0.05). The bars showing different letters represent the values that differ significantly from each other (p < 0.05).