Figure 3

Gilt and fetal level predictors of the odds of fetal death. Grey font (text box at bottom right) indicates variables that were included in the full model (P < 0.05 in unconditional analyses), but were excluded from final models due to non-significance during stepwise backwards elimination. Levels of IFNα in supernatants of PRRSV stimulated PBMC over time (IFNα_sup_PRRSV AUC0-19) increased the odds of fetal death (red arrows), while absolute numbers of T helper lymphocytes early after infection (Th cells AUC0-6) were protective (green arrow). The presence of PRRSV RNA (PRRSV RNA within fetus), adjacent PRRSV RNA positive fetuses (No. PRRSV RNA positive neighbors), and adjacent dead fetuses (No. dead neighbors) significantly increased the odds of fetal death. Assessment of PRRSV RNA concentration measured at the maternal-fetal interface (PRRSV VL MF_interface) required the inclusion of a quadratic term in the statistical model (blue arrow). Low viral load at the MF interface was associated with increasing odds of fetal death, while high viral load was associated with decreasing odds of fetal death. P-values and odds ratios are indicated for all significant factors.