A comparison of the safety, cross-protection, and serologic response associated with two commercial oral Salmonella vaccines in swine
Jeffrey A. Husa, DVM; Roy A. Edler, MS; Donald H. Walter, DVM; J. Tyler Holck, DVM, MS, MBA; Ryan J. Saltzman, DVM
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Objectives: To compare safety, cross-protection, and serologic response associated with two Salmonella serovar Choleraesuis vaccines.
Materials and methods: Eighty 4-week-old pigs, seronegative and culture-negative for Salmonella, were assigned to four groups of 20. The nonvaccinated challenged control group (NVC) was inoculated with virulent Salmonella serovar Typhimurium. Two groups received either Enterisol SC-54 (SC-54; Boehringer Ingelheim Vetmedica Inc, St Joseph, Missouri) or Argus SC/ST (Argus; Intervet Inc, Millsboro, Delaware) avirulent live Salmonella serovar Choleraesuis vaccines (Day 0) and were challenged (Day 43) with Salmonella serovar Typhimurium. The strict control group (NVNC) was nonvaccinated and nonchallenged. Individual body weights, clinical scores, rectal temperatures, and necropsy observations were recorded. Salmonella serum antibodies were measured using an indirect ELISA (Idexx Laboratories, Westbrook, Maine).
Results: After vaccination, the Argus group showed more severe and frequent pyrexia and lower average daily gain (ADG) and Day 43 body weights than the SC-54 and NVC groups (P < .05). Vaccinates demonstrated cross-protection against Salmonella Typhimurium, with less severe and frequent pyrexia and lower individual clinical scores (P < .05). Prevalence of enteric lesions and total clinical scores were lower with SC-54 (P < .05). Vaccinal seroconversion was not detected pre-challenge, despite demonstrated cross-protection. By Day 52, 95% to 100% of all challenged pigs seroconverted.
Implications: Enterisol SC-54 causes no adverse effects. Argus SC/ST induces significant deleterious responses. Both vaccines confer Salmonella Typhimurium cross-protection, with greater cross-protection by SC-54. As vaccinal seroconversion is not detected, monitoring programs using this ELISA are unlikely to be confounded by vaccination.
Keywords: Salmonella, Typhimurium, vaccine, safety, efficacy
Cite as: Husa JA, Edler RA, Walter DH, et al.. A comparison of the safety, cross-protection, and serologic response associated with two commercial oral Salmonella vaccines in swine. J Swine Health Prod 2009;17(1):10-21.
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