Comparative Efficacy of Two PRRSV and PCV2 Vaccines

Abstract

Porcine reproductive and respiratory syndrome (PRRS) induced by PRRS virus (PRRSV) has led to the most devastating economic losses in the global swine industry because PRRSV causes reproductive failure in breeding herds and respiratory disorder in growing/finishing pigs. Vaccination has become the most common strategic method for the prevention and control of PPRSV infection. Since simultaneous immunization is an efficient tool for controlling the co-challenge of PCV2 and PRRSV infection, the objective of the first study was to compare clinical, virological, immunological, and pathological indicators in pigs each treated simultaneously with both PRRSV and porcine circovirus type 2 (PCV2) vaccines from one of two commercial products and then later exposed to field strains of both viruses. Pigs in one group vaccinated with Fostera PCV and Fostera PRRS simultaneously and pigs in another group vaccinated with Ingelvac CircoFLEX and Ingelvac PRRS MLV simultaneously on study day -28 (21 days of age) were exposed to both viruses at study day 0 (49 days of age). No significant differences concerning transmission were seen between the two immunized groups in clinical, virological (except PCV2 viremia on day 14), immunological, or pathological examinations. Under these study conditions, there was no difference in protection whether PCV2 and PRRSV vaccines were administered simultaneously or not. The objective of the second study was to compare the efficacy of two modified live virus (MLV) PRRSV vaccines under field conditions. The clinical trial at the site was performed on a 1,000-sow herd with two-site generation: farrowing nursery and growing/finishing system. The farm had had difficult times because of losing animals due to respiratory disease brought on by PRRSV-2 in postweaning and late growing pigs at the same time of study. Via intramuscular injections, pigs in Group 1 were administered with 2.0 mL of the Fostera PRRS vaccine (Zoetis, Lot No. A405013B), pigs in Group 2 were administered with 2.0 mL of the Ingelvac PRRS MLV (Boehringer Ingelheim Vetmedica Inc., Lot No. 245-659A) and pigs in Group 3 were administered with 2.0 mL of phosphate buffered saline (0.01M, pH 7.4). This study indicated that pigs immunized with MLV vaccines Fostera PRRS (Zoetis, Florham New Jersey) and Ingelvac PRRS MLV (Boehringer Ingelheim Vetmedica Inc., St Joseph Missouri) showed better growth performance and less lung lesions than unvaccinated controls under wild conditions. Moreover, no significant differences were detected between the MLV PRRSV vaccines in this study based on clinical (average daily weight gain), immunologic (antibodies), virologic (PCR testing), and pathologic (lesions and viral antigen) measurements.