The Importance of Monitoring PCV2 virus and PCV2 Antibodies

PCV2 virus (PCV2) causes economic damage and is a risk factor in swine production. Vaccination coverage is > 85%. Scientific literature reports differences in protection. Subclinical PCVAD (PCVAD-SI) can occur in vaccinated herds. In protection against PCV2 infection both Virus Neutralizing antibodies (VN) and Cell Mediated Immunity (CMI) are important. Maternally Derived Antibodies (MDA) are protective and the titer height varies among piglets. High MDA titers at vaccination will interfere with vaccination and seroconversion. Seroconversion after vaccination is a clear sign of successful vaccination. When protection is optimized the resulting financial gains can be substantial, for example by creating uniformity in MDA titers through sow vaccination, combined with a better timing of piglet vaccination. Protection after vaccination can be monitored by checking for PCV2 antibodies (BioChek PCV2 ELISA) and for PCV2 viral load (BioChek PCV2 qPCR).

Literature was screened for mode of action of PCV2, PCV2 induced immunity, the importance of sub-clinical infections, differences in control of PCV2 infection by vaccination and differences in economic performance. Investigations by BioChek on PCV2 monitoring by ELISA and qPCR was included.

PCV2 virus alters cytokine production, impairing the immune response. Studies have shown that vaccines can be efficacious and that vaccinated groups perform better than control groups. Control groups have more animals with PCV2 viremia and infected animals have higher PCV2 viral load. PCV2 immunity depends on VN antibodies and CMI. When sero-conversion is observed after vaccination, CMI is also induced. Groups with higher seroconversion measured by ELISA and with a higher level of uniformity in titers showed a lower level of PCV2 (qPCR) viremia and recorded a better economic performance. When vaccination is monitored for sero-conversion and viral load, the optimal vaccination moment can be determined. The BioChek PCV2 monitoring system reports both antibody titers and viral load, and includes the Coefficient of Variation (CV%). CV% indicates the level of uniformity within a batch. Lack of uniformity in serological protection is a factor leading to the biological variation often observed in PCVAD.

PCVAD-SI is of economic importance. PCVAD-SI can be detected by generating information on PCV2 antibody titers and PCV2 viral load. BioChek PCV2 ELISA and qPCR test kits provide information on efficacy of vaccination, serological uniformity and quality of PCV2 control. Substantial financial gains are reported by using this system.

Disclosure of Interest: None Declared.