Analysis of efficacy obtained with a trivalent inactivated <i>Haemophilus parasuis</i> serovars 4, 5, and 12 vaccine and commercial vaccines against Glässer's disease in piglets.

Abstract

The objective of this study was to assess the efficacy of a trivalent inactivated <i>Haemophilus parasuis</i> serovars 4, 5, and 12 vaccine with polymeric adjuvant gel (GEL) and commercial vaccines against Glässer's disease in piglets. Commercial vaccines containing inactivated <i>H. parasuis</i> serovars 4 and 5 (China), inactivated <i>H. parasuis</i> serovars 1 and 6 (Spain), and inactivated <i>H. parasuis</i> serovar 5 (USA) were also evaluated. Our results demonstrated that the trivalent inactivated <i>H. parasuis</i> serovars 4, 5, and 12 vaccine with GEL adjuvant can provide better protection against the 3 most common pathogenic serovars circulating in China than other commercial vaccines tested. Our findings also indicated that inactivated <i>H. parasuis</i> serovars 1 and 6 vaccine cross-protects piglets against <i>H. parasuis</i> serovars 4 and 5; inactivated <i>H. parasuis</i> serovar 5 vaccine cross-protects piglets against <i>H. parasuis</i> serovar 4 challenge; but none of the commercial vaccines tested in this study protected piglets against <i>H. parasuis</i> serovar 12. Our results provide a basis for further identification of common protective antigens that can induce cross-protection against heterogeneous serovars.