Comparative study of the humoral immune responses developed by 5 commercial monovalent Erysipelothrix rhusiopathiae vaccines

The aim of this study was to compare the humoral immune responses elicited in naïve pigs by five different inactivated monovalent Erysipelothrix rhusiopathiae vaccines.

A controlled, blinded field study was performed on a 360-sow farm located in Catalonia (Spain). A total of one hundred and eighty 13-week-old pigs, clinically healthy and free from antibodies against E. rhusiopathiae, were randomly assigned to six different groups. Animals from groups 1 to 5 were immunised twice i.m. (2 ml/dose, at 13 and 16 weeks of age approx.) with five different commercially available vaccines in Europe. Group 1 was immunised with ERYSENG®, a vaccine adjuvanted with Hipramune® G^d, and groups 2-4 were immunised with three different swine erysipelas monovalent vaccines. Animals from the control group (Group 6) received a phosphate buffered saline (PBS) following the same schedule. 15 serum samples/group were obtained on days 0, 19, 47 and 78 and antibodies to E. rhusiopathiae (IgG) were titrated using a commercially available ELISA (CIVTEST® SUIS SE/MR). Samples were considered positive when IRPC ≥ 40. Antibody titres were compared between groups using the Kruskall-Wallis test (p< 0.05).

E. rhusiopathiae antibody titres from group 1 (ERYSENG®) were the highest throughout the fattening period and showed statistically significant differences to groups 2, 4 and 5 on day 19 and groups 2 and 5 on day 47 (p< 0.05). A decrease in the mean E. rhusiopathiae titres for all vaccinated groups was observed from day 47 onwards. At the end of the study (day 78) the group vaccinated with ERYSENG® was the only one which showed statistically significant differences to the control group. The control group remained negative and stable during the entire fattening period.

The percentage of seropositive pigs in the ERYSENG® group was the highest of all the different commercial vaccines during the entire study. At the end of the fattening period, around 80% of the animals vaccinated with ERYSENG® were seropositive, with titres above the cut-off (IRPC ≥ 40). While the percentage of seropositive samples from the other groups was: 40% (group 2), 46% (group 3), 22% (group 4) and 60% (group 5).

The humoral immunity elicited by ERYSENG® was faster, higher and lasted longer than the humoral immune response developed by the other commercial vaccines. ERYSENG® provided the best humoral protection during the entire fattening period.

Disclosure of Interest: None Declared.