Scatter plots of selected cytokines in serum and supernatants of PRRSv stimulated PBMC versus viral load in gilt serum or percent dead fetuses per litter. The levels of IFNα (A) and CCL2 (B) in serum over time are plotted against the viral load in gilt serum over time (area under the curve (AUC) from 0 to 21 dpi) illustrating individual variation. (C) The levels of IFNα in supernatants of PRRSv stimulated PBMC over time (AUC) are plotted against the percentage of dead fetuses per litter. Animals in the upper right quadrant are helping to drive the relationship. No gilts had high cytokine levels and low viral load in serum or low percent of dead fetuses per litter.