Comparison of three enzyme-linked immunosorbent assays to detect Porcine circovirus-2 (PCV-2)-specific antibodies after vaccination or inoculation of pigs with distinct PCV-1 or PCV-2 isolates

Porcine circovirus-2 (PCV-2) serology is frequently used to determine PCV-2 status and optimal timing of PCV-2 vaccination in the field. The objectives of the current study are to determine the diagnostic accuracy of 3 currently available commercial anti-immunoglobulin G (IgG) PCV-2 enzyme-linked immunosorbent assays (ELISAs) and to compare the ability of the 3 assays to detect and differentiate between anti-PCV-2a and anti-PCV-2b antibodies, as well as anti-PCV-2 and anti-PCV-I antibodies. Fifty-five 3-week-old, conventional pigs were randomly allocated to 7 groups: 1) negative controls (n = 7), 2) PCV-2a (n = 8; inoculated with PCV-2 ISU-40895), 3) PCV-2b (n = 8; inoculated with PCV-2 NC-16845), 4) PCV-1 (n = 8), 5) vaccine A (n = 8; Ingelvac® CircoFLEX™), 6) vaccine B (n = 8; Circumvent® PCV2), and 7) vaccine C (n = 8; Suvaxyn® PCV2 One Dose). Blood samples were collected weekly, and all sera were tested by 3 different anti-PCV-2 IgG ELISAs. The results indicated that all ELISAs had area under the receiver operating curve values greater than 0.94, detected both anti-PCV-2a and -2b antibodies with no differentiation, and did not detect anti-PCV-1 antibodies in infected animals. One of the ELISAs was able to distinguish pigs vaccinated with vaccine B from pigs inoculated with either PCV-2a or PCV-2b.