The Role of Host Genotypes in the Susceptibility to Porcine Circovirus Associated Diseases

Porcine Circovirus 2 (PCV2) is a small (1.7kb), circular, single-stranded DNA virus. Infected pigs become seropositive between 6-18 weeks of age with 5-15% eventually displaying clinical signs of Porcine Circovirus Associated Diseases (PCVAD). Vaccination is costly given the small percentage of affected pigs. • PCVAD is usually expressed between 90-120 days of age and commonly manifests as Post-weaning Multi-systemic Wasting Syndrome (PMWS), Porcine Dermatitis and Nephropathy Syndrome, Porcine Respiratory Disease Complex, enteritis, reproductive failure and enlarged lymph nodes / lymphoid depletion. • Previous research using genome wide association analysis uncovered two SNPs that explain 12.4% (SSC12) and 3.7% (SSC7) of the genetic variation for viral load, respectively. The position of the SNP located on SSC12 was initially unassigned but was putatively located to the proximal end of SSC12 based on linkage disequilibrium. The CC genotype of this QTL was found to be associated with lower viral load (p\u3c0.0001) and higher ADG (p\u3c0.05) when compared with both the CT and TT genotypes (Engle et al., 2014). • SOCS3 is a candidate gene identified through functional analysis of potential protein coding genes located in the QTL region mapped on SSC12. • SOCS3 is a cytokine signaling suppressor gene involved in the function of the mammalian immune response