Background: In the last years, Leptospira spp Ballum has increased its representation in human clinical isolations in Cuba. Effective vaccines are needed to control this zoonotic disease.
Objective: With the objective of developing a new vaccine candidate able to generate an effective protection against this serovar, two monovalent formulations developed by two highly virulent strains were evaluated (FoBa and FoBb).
Methods: Clinical isolates of Leptospira serovar Ballum were subjected to serial passages in hamsters and monovalent vaccines were produced by modified methods developed for vax-SPIRAL®. The vaccine efficacy was tested in both experimental and control hamsters.
Results: The Mesocricetus auratus biomodel showed that both formulations generated a protection of 100% against the Ballum lethal infection together to high levels of IgG antibodies and were efficient in the elimination of homologous carrier state but not heterologous carrier states.
Conclusion: Both FoBa and FoBb vaccines were protective against leptospirosis with high IgG titers, absence of clinical signs and dead, and absence of leptospires in kidney of sacrificed animals.