A new Montanide™ Seppic IMS1313-adjuvanted autogenous vaccine as a useful emergency tool to resolve a Salmonella enterica subsp. enterica serovar abortus equi abortion outbreak in mares

Background: In Italy, an autogenous registered vaccine, adjuvanted with aluminum hydroxide, can be administrated to contrast Salmonella enterica subsp. enterica serovar abortus equi infection coupled to a specific antimicrobial treatment.Case Description: Here, we report the case of an abortion outbreak by Salmonella abortus equi in Central Italy where mares were vaccinated but immediately developed a strong local reaction, maybe due to the adjuvant. Promptly, another autogenous vaccine, substituting the aluminum hydroxide with a new generation adjuvant (Montanide (TM) Seppic IMS1313), was produced and administrated. The new formulated vaccine did not cause any adverse outcome and conferred high protection titers against the infection. To the best of our knowledge, this is the first reported case of immunization by a vaccine adjuvanted with Montanide (TM) Seppic IMS1313 in horses.Conclusion: This approach may be used as a preventive strategy for further outbreaks in association with the application of recommended biosafety principles.