Comparison of 3 vaccination strategies against porcine reproductive and respiratory syndrome virus, and porcine circovirus type 2 on a 3 pathogen challenge model.

The objective of this study was to compare clinical, microbiologic, immunologic, and pathologic parameters in pigs each concurrently administered porcine reproductive and respiratory syndrome virus (PRRSV), and porcine circovirus type 2 (PCV2) vaccine from 1 of 2 commercial sources at 21 days of age and challenged with field strains of each of the 3 pathogens. Pigs were challenged with PRRSV and at 42 days of age (-14 days post-challenge, dpc) followed by a challenge with PCV2 at 56 days of age (0 dpc). Significant differences were observed between vaccinated challenged and unvaccinated challenged groups in clinical (average daily gain and clinical signs), microbiologic (viremia and nasal shedding), immunologic (antibodies and interferon-γ secreting cells), and pathologic (lesions) outcomes. Significant differences were observed among the 3 vaccinated challenged groups in microbiologic (nasal shedding of and viremia of PCV2) and immunologic (- and PCV2-specific interferon-γ secreting cells) outcomes. The vaccination regimen for PRRSV vaccine, vaccine, and PCV2 vaccine is efficacious for controlling triple challenge with PRRSV, and PCV2 from weaning to finishing period.