The 2014 Symposium of Animal Vaccine Development Center

The efficacy of porcine reproductive and respiratory syndrome vaccine I

HY Lee, TT Peng, JP Wang, CY Fang, CF Lai, HC Tseng, WC Huang, CD Li, ZW Chen

Porcine reproductive and respiratory syndrome (PRRS) is a highly epidemic porcine disease which causes huge economic loss. The pathogen of PRRS is an enveloped single-strained RNA virus. PRRSV is transmitted by droplet contact, i.e. coughing or sneezing on another individual. The pig infected by PRRSV is sensitive to other pathogens due to the suppressed immunity. To prevent the economic loss in the pig herd, it is necessary to apply not only feeding management but also vaccination plan. Previous we developed a subunit vaccine of PRRSV. In this study, the efficacy of PRRSV vaccine was tested by PRRSV challenge model. Nine secondary SPF pigs were randomly divided into two immunized groups and one control group. The pigs received twice vaccination at 3 and 6 weeks old and PRRSV challenge at 8 weeks old. The commercial ELISA kits were used to examine the anti-PRRSV antibody in the porcine sera. Pathological examinations were carried out in the lung appearance and histologic sections to determine the interstitial pneumonia. The results indicated that one week after viral challenge, the antibody titers increased significantly in the immunized pigs, suggested that immunological memory was induced by vaccination. Pathological examinations showed that alveolar wall thickening and aggregation of lymphocytes in the small bronchi were observed in the control pigs. These results indicated that the developed PRRSV vaccine can induce antibody titers and reduce pathological syndromes in the pigs after PRRSV challenge.