Introduction: is a widespread respiratory pathogen in pigs, causing swine pneumonia and atrophic rhinitis, and the capsular serogroups A and D are the main epidemic serogroups in infected animals. This study investigated the protective effects of serogroup A and D bacterins against current circulating strains, to better understand the immunity generated by bacterins.
Method: 13 serogroup A (seven A: L3 and six A: L6 strains) and 13 serogroup D (all D: L6 strains) strains were isolated, and used as inactivated whole cell antigen to prepare bacterins.