Biomarkers for inflammation (haptoglobin, total proteins), immune response (adenosine deaminase), tissue damage (lactate dehydrogenase), stress (alpha-amylase), and sepsis (calprotectin, aldolase, Serpin B12) were measured in pigs under three clinical scenarios: (1) no evident clinical signs, (2) clinical signs indicating PRRSV activation, and (3) secondary bacterial infection by Streptococcus suis. The gene discussed is SERPINB12; the disease is bacterial infectious disease.